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Context: Loose tumor cells and tumor cell clusters can be recognized in the lumen of intratumoral pulmonary arteries of resected non-small cell lung cancer specimens. It is unclear whether these should be considered tumor-emboli, and as such could predict a worsened prognosis., Objective: To investigate the nature and prognostic impact of pulmonary artery intraluminal tumor cells., Design: This multicenter study involved an exploratory pilot study and a validation study from 3 institutions. For the exploratory pilot study, a retrospective pulmonary resection cohort of primary adenocarcinomas, diagnosed between November 2007 and November 2010, were scored for the presence of tumor cells, as well as potentially other cells in the intravascular spaces, using hematoxylin-eosin and cytokeratin 7 (CK7) stains. In the validation part, 2 retrospective cohorts of resected pulmonary adenocarcinomas, between January 2011 and December 2016, were included. Recurrence-free survival (RFS) and overall survival (OS) data were collected., Results: In the pilot study, CK7+ intravascular cells, mainly tumor cells, were present in 23 of 33 patients (69.7%). The 5-year OS for patients with intravascular tumor cells was 61%, compared with 40% for patients without intravascular tumor cells (P = .19). In the validation study, CK7+ intravascular tumor cells were present in 41 of 70 patients (58.6%). The 5-year RFS for patients with intravascular tumor cells was 80.0%, compared with 80.6% in patients without intravascular tumor cells (P = .52). The 5-year OS rates were, respectively, 82.8% and 71.6% (P = .16)., Conclusions: Loose tumor cells in pulmonary arterial lumina were found in most non-small cell lung cancer resection specimens and were not associated with a worse RFS or OS. Therefore, most probably they represent an artifact., Competing Interests: The authors have no relevant financial interest in the products or companies described in this article., (© 2024 College of American Pathologists.)

Purpose: The precise etiopathogenesis of human papillomavirus (HPV)-related oropharyngeal squamous cell carcinoma (OPSCC), and reasons for predilection for crypt epithelium, remain uncertain. The purpose of this study is to investigate the interaction between HPV and specific cytokeratins 7 (CK7) and 19 (CK19) in crypt epithelium., Methods: This is a retrospective cohort study of patients presenting between 1999 and 2015 at a tertiary referral center. CK7 and CK19 positivity and H Scores were determined by immunohistochemistry. Disease-specific and overall survival rates were analyzed., Results: There were 253 patients presenting with OPSCC (134), squamous cell carcinoma (SCC) of unknown primary site (22), and oral tongue SCC (97). Primary tumor CK7 and CK19 positivity and H Scores were significantly higher in HPV-positive OPSCC than HPV-negative OPSCC and oral tongue SCC. Higher CK19 Scores, but not CK7 Scores, were also seen in regional metastases from HPV-positive OPSCC than other sites. No impact on disease-specific or overall survival was identified on multivariate analysis., Conclusion: The increased expression of CK7 and CK19 in HPV-positive OPSCC compared to HPV-negative disease supports the theory for a role for these cytokeratins in the etiopathogenesis of HPV-related OPSCC., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Recently, the World Health Organization (WHO) recognized human papilloma virus (HPV)-independent invasive cervical squamous cell carcinoma (SCC) without recognizing the existence of precursor lesions. This is a detailed characterization of 3 preinvasive lesions and 6 invasive SCC negative for HPV-DNA (32 genotypes), HPV-mRNA (14 genotypes) and genomic HPV sequencing. We evaluated histologic features, expression of p16ink4a, p53, CK7, and CK17, aberrations in 50 cancer genes and chromosomal copy number variations. HPV-negative preinvasive lesions were extensive basaloid or highly differentiated keratinizing intraepithelial proliferations of 3 to 20 cell layers thickness, partly with prominent cervical gland involvement. Overall, 2/3 intraepithelial lesions and the in situ component of 1/6 SCC showed p16ink4a block staining, while 1/6 in situ component revealed heterogenous p16ink4a staining. All invasive components of keratinizing SCC were p16ink4a-negative. Preinvasive and invasive SCC showed inconsistent CK7 and CK17 staining. Nuclear p53 overexpression was restricted to the TP53 gene mutated SCC. The highly vascularized peritumoral stroma showed a dense inflammatory infiltrate including plasma cells and intratumoral and peritumoral eosinophilic granulocytes. Inconsistent somatic gene mutations (PIK3CA, STK11, TP53, SMARC2B, and GNAS) occurred predominantly in nonhotspot locations at low mutational frequency in 3/6 SCC. Consistent aberrations included the pathogenic (angiogenic) germline polymorphism Q472H in the KDR gene (7/9 patients), and chromosome 3q gains (4/9 patients). In conclusion, HPV-negative intraepithelial cervical precancerous lesions exist, either as highly differentiated keratinized intraepithelial proliferations reminiscent of differentiated vulvar intraepithelial neoplasia, or undifferentiated basaloid intraepithelial lesions with occasional p16ink4a block staining resembling high-grade squamous intraepithelial lesion. Gains of chromosome 3q, angiogenic germline variants the inflammatory infiltrate may contribute to progression of HPV-negative cervical carcinogenesis., Competing Interests: Conflicts of Interest and Source of Funding: The authors have disclosed that they have no significant relationships with, or financial interest in, any commercial companies pertaining to this article., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Mucin-producing salivary adenocarcinomas were historically divided into separate colloid carcinoma, papillary cystadenocarcinoma, and signet ring cell carcinoma diagnoses based on histologic pattern, but have recently been grouped together in the adenocarcinoma not otherwise specified category. It is currently unclear if these tumors represent 1 or more distinct entities and how they are related to well-circumscribed papillary mucinous lesions with recurrent AKT1 E17K mutations that were recently described as salivary intraductal papillary mucinous neoplasm. Here, we sought to evaluate the clinicopathologic and molecular features of salivary mucinous adenocarcinomas to clarify their classification. We identified 17 invasive mucin-producing salivary adenocarcinomas, 10 with a single histologic pattern, and 7 with mixed patterns. While most tumors demonstrated papillary growth (n=15), it was frequently intermixed with colloid (n=6) and signet ring (n=3) architecture with obvious transitions between patterns. All were cytokeratin 7 positive (100%) and cytokeratin 20 negative (0%). Next-generation sequencing performed on a subset demonstrated recurrent AKT1 E17K mutations in 8 cases (100%) and TP53 alterations in 7 cases (88%). Of 12 cases with clinical follow-up (median: 17 mo), 4 developed cervical lymph node metastases, all of which had colloid or signet ring components. Overall, overlapping histologic and immunohistochemical features coupled with recurrent AKT1 E17K mutations across patterns suggests that mucin-producing salivary adenocarcinomas represent a histologically diverse single entity that is closely related to tumors described as salivary intraductal papillary mucinous neoplasm. We propose a unified mucinous adenocarcinoma category subdivided into papillary, colloid, signet ring, and mixed subtypes to facilitate better recognition and classification of these tumors., Competing Interests: Conflicts of Interest and Source of Funding: Supported in part by the Jane B. and Edwin P. Jenevein, MD Endowment for Pathology at UT Southwestern Medical Center. The authors have disclosed that they have no significant relationships with, or financial interest in, any commercial companies pertaining to this article., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Mammary Paget's disease accounts for 1% to 3% of all breast tumors and manifests as a chronic eczematous lesion of the areolar skin. It can occur without any underlying neoplasia or can be present in association with an underlying invasive and/or in situ carcinoma of the breast. The present report describes a challenging nipple punch biopsy showing an infiltration of the lower third to two-thirds of the epidermis by large, ovoid, neoplastic cells. The morphology was consistent with mammary Paget's disease, although immunohistochemistry for cytokeratin-7 (CK7) was repeatedly negative. This resulted in an initial misdiagnosis and, subsequently, a delay in the patient's follow-up. Additional immunohistochemistry for GATA binding protein 3 (GATA3) and human epidermal growth factor receptor 2 (HER2), as well as a second opinion of a breast pathologist, resulted in the diagnosis of mammary Paget's disease. The aim of this article is to raise awareness among pathologists and prevent them from misdiagnosing CK7-negative Paget disease of the breast.

Primary gastrointestinal neuroendocrine carcinoma (GI-NEC) cannot be distinguished morphologically from pulmonary neuroendocrine carcinoma (P-NEC). This can present a significant diagnostic challenge in cases where site of origin cannot be readily determined. To identify immunohistochemical (IHC) markers that can be used to reliably distinguish between GI-NECs and P-NECs, we constructed 3-mm tissue microarrays, one containing 13 GI-NECs and one containing 20 P-NECs. IHC was performed on both microarrays using 21 stains: AE1/AE3, CK7, CK20, synaptophysin, chromogranin, CD56, INSM1, SSTR2A, CDX2, SATB2, TTF1, Napsin A, PR, GATA3, PAX8, ISL1, beta-catenin, AFP, SMAD4, Rb, and p53. For GI-NEC, the most strongly expressed marker was synaptophysin (mean H-score 248), while AE1/AE3 was the most strongly expressed in P-NEC (mean H-score 230), which was stronger than in GI-NEC (p = 0.011). Other markers that were stronger overall in P-NEC than in GI-NEC included CK7 (p < 0.0001) and TTF1 (p < 0.0001). Markers that were stronger overall in GI-NEC than in P-NEC included SSTR2A (p = 0.0021), SATB2 (p = 0.018), CDX2 (p = 0.019), and beta-catenin (nuclear; p = 0.029). SMAD4, Rb, and p53 showed similar rates of abnormal protein expression. Based on these results, a stepwise algorithmic approach utilizing CK7, TTF1, beta-catenin, CDX2, and SSTR2A had a 91% overall accuracy in distinguishing these GI-NEC from P-NEC. This was tested on a second cohort of 10 metastatic GI-NEC and 10 metastatic P-NEC, with an accuracy in this cohort of 85% and an overall accuracy of 89% for the 53 cases tested. Our algorithm reasonably discriminates GI-NEC from P-NEC using currently available IHC stains., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The origin of human metaplastic states and their propensity for cancer is poorly understood. Barrett's esophagus is a common metaplastic condition that increases the risk for esophageal adenocarcinoma, and its cellular origin is enigmatic. To address this, we harvested tissues spanning the gastroesophageal junction from healthy and diseased donors, including isolation of esophageal submucosal glands. A combination of single-cell transcriptomic profiling, in silico lineage tracing from methylation, open chromatin and somatic mutation analyses, and functional studies in organoid models showed that Barrett's esophagus originates from gastric cardia through c-MYC and HNF4A-driven transcriptional programs. Furthermore, our data indicate that esophageal adenocarcinoma likely arises from undifferentiated Barrett's esophagus cell types even in the absence of a pathologically identifiable metaplastic precursor, illuminating early detection strategies., (Copyright © 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Following lung cancer, breast cancer is the second most common metastatic tumor to the brain, of which triple-negative breast cancer (TNBC) and human epidermal growth factor receptor 2+ (HER2+) breast cancer are the most common subtypes. TNBC does not have standard immunoprofiles and can be difficult to distinguish from other metastases. A tissue microarray was created from 47 patients with breast cancer metastases to the brain and 12 paired breast primaries. Of 47 breast cancer metastases, 24 were HER2+, 14 were TNBC, and 9 were luminal. Forty-five were cytokeratin 7 (CK7) positive, 36 were GATA-binding protein 3 (GATA3) positive, 7 were Sry-related HMg-Box gene 10 (SOX-10) positive, 20 were mammaglobin positive, and 19 were gross cystic disease fluid protein 15 positive. At least one of the CK7, GATA3, or SOX-10 was positive in all TNBC metastases. A panel of CK7, GATA3, and SOX-10 is complementary in the diagnosis of breast cancer brain metastasis. SOX-10 appears to be a specific but not particularly sensitive marker in this context.

Low-grade oncocytic tumor of the kidney (LOT) is characterized by cytoplasmic eosinophilia and a CK7-positive/CD117-negative immunophenotype. Morphologically, they exhibit overlapping features with oncocytoma and chromophobe renal cell carcinoma. Our aim was to obtain long-term clinical follow-up data, clinicopathological and molecular characteristics, and incidence of LOT. Tissue microarrays were constructed from 574 tumors historically diagnosed as oncocytoma and surgically treated at Mayo Clinic between 1970 and 2012, and immunostained for CK7 and CD117. An extended immunophenotype was obtained on whole slide sections, along with FISH for CCND1 rearrangement status and chromosomal microarray for copy number status. In addition, two cases were retrospectively identified in a set of tuberous sclerosis complex (TSC)-associated neoplasms and three more cases diagnosed on needle core biopsies were obtained during routine clinical practice. Twenty-four cases of LOT were identified among 574 consecutive tumors diagnosed as oncocytoma and treated with partial or radical nephrectomy, corresponding to an incidence of 4.18% of tumors historically diagnosed as oncocytomas, and 0.35% of 6944 nephrectomies performed between 1970 and 2012. Overall, 29 cases of LOT were identified in three clinical settings: sporadic, TSC-associated, and end-stage renal disease (ESRD). Multifocality was seen only in the setting of TSC and ESRD. No metastases attributable to LOT were identified (median follow-up 9.6 years). There were no recurrent arm level copy number changes detected by chromosomal microarray and all tested cases were negative for CCND1 rearrangement by FISH. LOT is an uncommon eosinophilic renal neoplasm with an indolent prognosis that constitutes ∼4% of tumors historically diagnosed as oncocytoma. The morphologic, immunophenotypic, and molecular features of this neoplasm suggest it is a distinct entity of renal neoplasia., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Abstract: Trichilemmal cysts are common clonal tumors with a predilection for the scalp. They are composed of an outer epithelial wall resembling the outer root sheath in the isthmus of the hair follicle and a central core of compact keratin. Sweat duct differentiation is exceptional with only one convincing case reported to date. Here, we sought to characterize the clinicopathological characteristics of sweat duct differentiation in trichilemmal cysts. We reviewed all cases of trichilemmal cyst diagnosed at our institution between 2008 and 2019. Ductal structures were found in 4 of 411 cases (0.97%). Subjects included 2 male and 2 female patients with a median age of 37.5 years (range 34-55). The ducts were lined by attenuated epithelial cells and immunoreactive for polyclonal carcinoembryonic antigen and cytokeratin 7. Ductal differentiation involved a median of 7.5% (range 1%-50%) of the cyst wall. All 4 cases were from the scalp and treated with local excision. No recurrence was identified with a median follow-up period of 1.5 years (range 1-12 years). In summary, sweat duct differentiation in trichilemmal cysts is rare but likely under recognized. Conceptually, we suggest it represents a type of divergent cellular differentiation within a clonal neoplasm rather than a retention cyst or hybrid cyst., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

Background: The objective was to build a novel method for automated image analysis to locate and quantify the number of cytokeratin 7 (K7)-positive hepatocytes reflecting cholestasis by applying deep learning neural networks (AI model) in a cohort of 210 liver specimens. We aimed to study the correlation between the AI model's results and disease progression. The cohort of liver biopsies which served as a model of chronic cholestatic liver disease comprised of patients diagnosed with primary sclerosing cholangitis (PSC)., Methods: In a cohort of patients with PSC identified from the PSC registry of the University Hospital of Helsinki, their K7-stained liver biopsy specimens were scored by a pathologist (human K7 score) and then digitally analyzed for K7-positive hepatocytes (K7%area). The digital analysis was by a K7-AI model created in an Aiforia Technologies cloud platform. For validation, values were human K7 score, stage of disease (Metavir and Nakunuma fibrosis score), and plasma liver enzymes indicating clinical cholestasis, all subjected to correlation analysis., Results: The K7-AI model results (K7%area) correlated with the human K7 score (0.896; p < 2.2e - 16 ). In addition, K7%area correlated with stage of PSC (Metavir 0.446; p < 1.849e - 10 and Nakanuma 0.424; p < 4.23e - 10 ) and with plasma alkaline phosphatase (P-ALP) levels (0.369, p < 5.749e - 5 )., Conclusions: The accuracy of the AI-based analysis was comparable to that of the human K7 score. Automated quantitative image analysis correlated with stage of PSC and with P-ALP. Based on the results of the K7-AI model, we recommend K7 staining in the assessment of cholestasis by means of automated methods that provide fast (9.75 s/specimen) quantitative analysis.

To examine the clinicopathologic and immunohistochemical features of a group of newly defined low-grade oncocytic renal tumors (LOT) that have the "CD117 negative/cytokeratin (CK)7 positive" immunoprofile. We have queried our hospital database and found 4456 consecutive renal tumors between 2016 and 2019. Among these renal tumors, eight (8) cases meet the morphologic and immunohistochemical characterization for low-grade oncocytic renal tumor (LOT). The eight (8) patients' mean age is 56.6 years (range 39-70 years old), and the male to female ratio is 1:1. Macroscopically, these LOTs generally present with tan-brown and solid cut surfaces and demonstrate similar solid, compact nested growth pattern microscopically. Tumor cells exhibit oncocytic cytoplasm and uniformly rounded to oval nuclei. There are areas of edematous stroma containing dispersed single or small clustered tumor cells. All tumors are negative for CD117 and positive for CK7. Uniform reactivity is also found for BerEP4, cyclin D1, and SDHB. Besides, CD10, vimentin, and AMACR are either negative or only focally positive. All of the tumors are negative for CA9 and TFE. The Ki-67 index is less than 5% in the seven (7) internal cases. Seven (7) of the eight (8) patients who are available for follow-up are alive and without disease recurrence (mean follow-up period of 21.6 months, ranging from 6 to 43 months). We described a group of low-grade oncocytic renal tumors identified retrospectively in a large tertiary cancer center, which was probably the first report originated from China or even Asia in the English literature so far. These tumors demonstrated eosinophilic cytoplasm and low-grade appearing nuclei with a "CD117 negative/CK7 positive" immunoprofile. The incidence rate was about 3.7% of the oncocytic renal tumors and 0.18% of all the renal tumors that were received in our lab during the four-year period. It is necessary to separate this group of tumors by its characteristic morphologic and immunophenotypic features.

The histologic features of renal oncocytoma (RO) are similar to those for the more aggressive chromophobe renal cell carcinoma (ChRCC). To assess immunohistochemical markers of the two, the sensitivity and specificity of cytokeratin 7 (CK7) and C-kit, as well as hepatocyte nuclear factor-1β (HNF-1β), were analyzed. Typical cases of ChRCC and RO at Severance Hospital between July 2014 and July 2018 were selected retrospectively. Among 44 cases, 17 were unanimously compatible with ChRCC, 16 were RO, and 11 cases were indeterminate. Samples from all selected cases were used for immunostaining with antibodies against CK7, C-kit, HNF-1β, and CD10. Immunostaining demonstrated complete loss of HNF-1β expression in 11 out of 17 (64.7%) ChRCC cases and a partial, but significant loss in > 50% of tumor cells in the remaining 6 cases (35.3%). In contrast, HNF-1β expression was preserved in tumor cells of RO cases. Fourteen of 17 ChRCC cases (82.4%) were diffusely positive for CK7, whereas cases of RO were focal positive or negative. C-kit staining did not show a significant difference between ChRCC and RO. Two of five ChRCC cases showing diffuse immunoreactivity for CD10 had poor prognoses of local invasion, distant metastasis, or death. Loss of HNF-1β expression is a useful marker with which to diagnose ChRCC, especially in cases with confusing histologic findings or equivocal CK7 staining. Additionally, CD10 staining in high-grade ChRCC aids in diagnosis and prediction of the clinical prognosis.

Biopsies of liver mass lesions are encountered frequently in general surgical pathology practice. The clinical differential diagnosis is typically hepatocellular carcinoma (HCC) versus metastatic adenocarcinoma. There are a variety of HCC variants that show a range of morphological appearances. The presence of malignant glands in the liver prompts the pathologist to consider adenocarcinoma, either metastatic or primary intrahepatic cholangiocarcinoma. It is important to remember that some variant patterns of HCC can show pseudoglandular growth. In this article, we present a case of fibrolamellar carcinoma that showed predominantly pseudoglandular growth to highlight the importance of a systematic approach and the routine use of a panel of immunohistochemical stains (HepPar1, CK7, and CD68).

Morphology, clinical behavior, and genomic profiles of renal oncocytoma (RO) and its malignant counterpart chromophobe renal cell carcinoma (ChRCC) are distinctly different. However, there is a substantial group of sporadic oncocytic tumors with peculiar hybrid phenotypes as well as a perplexing degree of morphologic and immunohistochemical overlap between classic RO and ChRCC with eosinophilic cytoplasm. The aim of this study is to provide detailed characterization of these hybrid tumors.Thirty-eight sporadic oncocytic neoplasms with ambiguous morphology from two institutions were reviewed by 4 pathologists. CKIT positivity was used as a selection criterion. We correlated CK7 and S100A1 immunostaining and detailed morphologic features with cytogenetic profiles. DNA from the formalin-fixed paraffin-embedded tissues was extracted and analyzed using cytogenomic microarray analysis (CMA) to evaluate copy number alterations (CNA) and ploidy. CMA categorized cases into 3 groups: RO (N = 21), RO variant (N = 7), and ChRCC (N = 10). Cytogenetic RO had either no CNA (48%) or loss of chromosome 1p, X, or Y (52%). RO variant had additional chromosomal losses [-9q, -14 (n = 2), -13] and chromosomal gains [+1q (n = 2), +4, +7 (n = 2), +13, +19, +20, and +22]. ChRCCs were either hypodiploid with numerous monosomies (40%) or hypotetraploid with multiple relative losses (60%). RO, RO variant, and ChRCC groups differed significantly in tumor architecture (p < 0.01), stroma (p = 0.013), presence of nuclear wrinkling, perinuclear halos, and well-defined cell borders in >5% of cells (p < 0.01), focal cell clearing (p = 0.048) and CK7 expression (p < 0.02). Pathologic prediction of the cytogenetic subtype using only two categories (benign RO or malignant ChRCC) would overcall or undercall up to 40% of tumors that were ChRCC based on cytogenetics. This finding provides the rationale for an intermediate diagnostic category of the so-called hybrid tumors (hybrid oncocytic/chromophobe tumor [HOCT]). HOCT was a heterogeneous group enriched for cytogenetic RO variant. Other HOCTs have a profile of either RO or ChRCC. The genomic profile allows classification of oncocytic tumors with ambiguous morphology into RO, RO variant, and ChRCC. Several architectural and cytologic features combined with CK7 expression are significantly associated with cytogenetic RO, RO variant, or ChRCC tumors. Doubled hypodiploidy by whole-genome endoduplication is a common phenomenon in eosinophilic ChRCC., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objectives: To investigate the expression of various immunohistochemical markers in Mammary Paget's disease (MPD) and MPD-associated breast carcinoma and to evaluate their value in establishing the diagnosis., Methods: This retrospective descriptive study was carried out at King Faisal Specialist Hospital and Research Center and King Khalid University Hospital, Riyadh, Saudi Arabia. All MPD cases reported between January 2010 and June 2016 were selected from the surgical pathology records.  Immunohistochemical staining was carried out for cytokeratin 7 (CK7), GATA-binding protein 3 (GATA3), human epidermal growth factor receptor 2 (HER2), and estrogen, and progesterone receptors. Results: Twenty-two cases of MPD and 20 cases of MPD-associated breast carcinoma were included. CK7 was positive in 95% (21/22) cases of MPD and in all (20/20) cases of associated breast carcinoma. Similarly, GATA3 was expressed in 95% cases of both MPD (21/22) and associated breast carcinoma (19/20). Human epidermal growth factor receptor 2 was also overexpressed in 90% cases of MPD (20/22) and associated breast carcinoma (18/20). Estrogen stained positive in 27% cases of MPD (6/22) and 30% of cases of associated breast carcinoma (6/20). Progesterone receptors was not positive in any case of MPD; however, it was seen positive in 25% cases of MPD-associated breast carcinoma (5/20)., Conclusions: CK7, GATA3, and HER2 are widely expressed in MPD and MPD-associated breast carcinoma. These markers can be used for the immunohistochemical confirmation of MPD including CK7-negative cases.

Primary ovarian mucinous tumors can be difficult to distinguish from metastatic gastrointestinal neoplasms by histology alone. The expected immunoprofile of a suspected metastatic lower gastrointestinal tumor is CK7 - /CK20 + /CDX2 + /PAX8 - . This study assesses the addition of a novel marker SATB2, to improve the diagnostic algorithm. A test cohort included 155 ovarian mucinous tumors (105 carcinomas and 50 borderline tumors) and 230 primary lower gastrointestinal neoplasms (123 colorectal adenocarcinomas and 107 appendiceal neoplasms). All cases were assessed for SATB2, PAX8 CK7, CK20, and CDX2 expression on tissue microarrays. Expression was scored in a 3-tier system as absent, focal (1-50% of tumor cells) and diffuse ( >50% of tumor cells) and then categorized into either absent/present or nondiffuse/diffuse. SATB2 and PAX8 expression was further evaluated in ovarian tumors from an international cohort of 2876 patients (expansion cohort, including 159 mucinous carcinomas and 46 borderline mucinous tumors). The highest accuracy of an individual marker in distinguishing lower gastrointestinal from ovarian mucinous tumors was CK7 (91.7%, nondiffuse/diffuse cut-off) followed by SATB2 (88.8%, present/absent cut-off). The most effective combination was CK7 and SATB2 with accuracy of 95.3% using the 3-tier interpretation, absent/focal/diffuse. This combination outperformed the standard clinical set of CK7, CK20 and CDX2 (87.5%). Re-evaluation of outlier cases confirmed ovarian origin for all but one case. The accuracy of SATB2 was confirmed in the expansion cohort (91.5%). SATB2 expression was also detected in 15% of ovarian endometrioid carcinoma but less than 5% of other ovarian histotypes. A simple two marker combination of CK7 and SATB2 can distinguish lower gastrointestinal from ovarian primary mucinous tumors with greater than 95% accuracy. PAX8 and CDX2 have value as second-line markers. The utility of CK20 in this setting is low and this warrants replacement of this marker with SATB2 in clinical practice.

Background: There is a morphological overlap among renal epithelial tumors, particularly chromophobe renal cell carcinoma (CHRCC), clear cell renal cell carcinoma (CCRCC), renal oncocytoma (RO), and papillary renal cell carcinoma (PRCC). Discriminating between these tumors is important but sometimes challenging. This study is aimed at evaluating the clinical usefulness of the combined immunochemistry for the "three 7" markers (CK7, CD117, and Claudin-7) to distinguish chromophobe renal cell carcinoma from these mimics., Methods: Immunochemical staining for CK7, CD117, and Claudin-7 was performed in 68 CHRCCs, 199 CCRCCs, 32 ROs, and 30 PRCCs. Fluorescence in situ hybridization (FISH) was performed in some cases to exclude CCRCC and PRCC. The sensitivity (SE) and specificity (SP) for CHRCC as well as the immunoreactivity of each marker and their combinations were statistically evaluated., Results: High positive rates for CK7 (94%), CD117 (87%), Claudin-7 (94%), and their combinations (CK7+CD117, 79%; CK7+Claudin-7, 88%; CD117+Claudin-7, 82%; CK7+CD117+Claudin-7, 76%) were observed in CHRCC compared to those in CCRCC, RO, and PRCC, with increasingly higher SP when combinations of the "three 7" markers were applied (CK7, 0.80; CD117, 0.82; Claudin-7, 0.78; CK7+CD117, 0.95; CK7+Claudin-7, 0.97; CD117+Claudin-7, 0.97; CK7+CD117+Claudin-7, 1)., Conclusion: CK7, CD117, and Claudin-7 are frequently expressed in CHRCC with high specificity. We recommend the routine use of these 3 markers as a routine panel when making a differential diagnosis of CHRCC and excluding other mimics., Competing Interests: The authors declare that they have no significant relationship with or financial interest in any commercial companies with regard to this article., (Copyright © 2019 Jun Zhou et al.)

Aim: To describe a group of distinct low-grade oncocytic renal tumours that demonstrate CD117 negative/cytokeratin (CK) 7-positive immunoprofile., Methods and Results: We identified 28 such tumours from four large renal tumour archives. We performed immunohistochemistry for: CK7, CD117, PAX8, CD10, AMACR, e-cadherin, CK20, CA9, AE1/AE3, vimentin, BerEP4, MOC31, CK5/6, p63, HMB45, melan A, CD15 and FH. In 14 cases we performed array CGH, with a successful result in nine cases. Median patient age was 66 years (range 49-78 years) with a male-to-female ratio of 1:1.8. Median tumour size was 3 cm (range 1.1-13.5 cm). All were single tumours, solid and tan-brown, without a syndromic association. On microscopy, all cases showed solid and compact nested growth. There were frequent areas of oedematous stroma with loosely arranged cells. The tumour cells had oncocytic cytoplasm with uniformly round to oval nuclei, but without significant irregularities, and showed only focal perinuclear halos. Negative CD117 and positive CK7 reactivity were present in all cases (in two cases there was focal and very weak CD117 reactivity). Uniform reactivity was found for PAX8, AE1/AE3, e-cadherin, BerEP4 and MOC31. Negative stains included CA9, CK20, vimentin, CK5/6, p63, HMB45, Melan A and CD15. CD10 and AMACR were either negative or focally positive; FH was retained. On array CGH, there were frequent deletions at 19p13.3 (seven of nine), 1p36.33 (five of nine) and 19q13.11 (four of nine); disomic status was found in two of nine cases. On follow-up (mean 31.8 months, range 1-118), all patients were alive with no disease progression., Conclusion: Low-grade oncocytic tumours that are CD117-negative/CK7-positive demonstrate consistent and readily recognisable morphology, immunoprofile and indolent behaviour., (© 2019 John Wiley & Sons Ltd.)

Histological processing of thermosensitive electrospun poly(ε-caprolactone)/poly(L-lactide) (PCL/PLA) scaffolds fails, as poly(ε-caprolactone) (PCL) is characterized by its low-melting temperature (Tm = 60 °C). Here, we present an optimized low-temperature preparation method for the histological processing of un-/cellularized thermosensitive PCL/PLA scaffolds.Our study is aimed at the establishment of an optimized dehydration and low-melting-point paraffin-embedding method of electrospun PCL/PLA scaffolds (un-/cellularized). Furthermore, we compared this method with (a) automatized dehydration and standard paraffin embedding, (b) gelatin embedding followed by automatized dehydration and standard paraffin embedding, (c) cryofixation, and (d) acrylic resin embedding methods. We investigated pepsin and proteinase K antigen retrieval for their efficiency in epitope demasking at low temperatures and evaluated protocols for immunohistochemistry and immunofluorescence for cytokeratin 7 (CK7) and in situ padlock probe technology for beta actin (ACTB). Optimized dehydration and low-melting-point paraffin embedding preserved the PCL/PLA scaffold, as the diameter and structure of its fibers were unchanged. Cells attached to the PCL/PLA scaffolds showed limited alterations in size and morphology compared to control. Epitope demasking by enzymatic pepsin digestion and immunostaining of CK7 displayed an invasion of attached cells into the scaffold. Expression of ACTB and CK7 was shown by a combination of mRNA-based in situ padlock probe technology and immunofluorescence. In contrast, gelatin stabilization followed by standard paraffin embedding led to an overall shrinkage and melting of fibers, and therefore, no further analysis was possible. Acrylic resin embedding and cyrofixation caused fiber structures that were nearly unchanged in size and diameter. However, acrylic resin-embedded scaffolds are limited to 3 µm sections, whereas cyrofixation led to a reduction of the cell size by 14% compared to low-melting paraffin embedding. The combination of low-melting-point paraffin embedding and pepsin digestion as an antigen retrieval method offers a successful opportunity for histological investigations in thermosensitive specimens.

Objective: To investigate the expression of immunomarkers CK7, CK20, CK17, CDX2, MUC1 and MUC2 in primary adenocarcinoma of the ampulla of Vater, to explore the role of these markers in the histopathologic subclassification of ampullary carcinoma; and to provide biologic basis for precision treatment of patients with different types of ampullary carcinoma. Methods: Forty-two cases of primary ampullary carcinoma were collected at Peking University People's Hospital, from 2012 to 2018 year. There were 22 males and 20 females. Aged range 42 to 88 years old, with mean aged (62±11) years. Among the patients, 6 was high differentiation, 19 median differentiation, and 17 low differentiation. Immunohistochemical studies on the expression of CK7, CK20, CK17, CDX2, MUC1 and MUC2 were performed in 42 cases of primary ampullary carcinoma. The relationship between different ampullary carcinoma subtypes and clinicopathologic survival data was analyzed using SPSS 16.0 statistical software. Results: Three histopathologic subtypes were observed. Among 42 cases, 8(19.0%)were classified as intestinal subtype, which showed a positive expression rate of 8/8 for both CK20 and CDX2, and 5/8 for MUC2. Both CK7 and CK17 were weakly expressed in one case (1/8). No expression was observed for MUC1 in this subtype. Twenty-two (52.4%,22/42) cases were classified as pancreaticobiliary subtype, which showed a positive expression rate of 100.0%(22/22) for both CK7 and MUC1, and 90.9% (20/22) for CK17. No expression was observed for CK20, CDX2 and MUC2.The remaining 12 (28.6%) cases were classified as mixed subtype, which showed variable expression patterns. The expression frequencies of these 6 immunomarkers in different subtypes of ampullary carcinoma did not correlate with various clinicopathologic factors such as patient gender and age, tumor size, histologic differentiation, pancreatic and bile duct invasion, or the depth of duodenal invasion. However, stage Ⅲ+Ⅳ diseases were more commonly seen in pancreaticobiliary type (63.6%,14/22) than intestinal type (2/8) and mixed type (3/9; χ(2)=6.508, P= 0.039). Follow-up data showed a trend of better survival rate for patients with intestinal subtype than those with mixed and pancreaticobiliary subtypes. Conclusions: Ampullary carcinoma can be subclassified into three different subtypes using a panel of six immunomarkers, especially for the identification of subtypes of poorly differentiated carcinoma. CK7, CK17 and MUC1 are major markers of pancreaticobiliary subtype, whereas CK20, CDX2 and MUC2 are useful markers for intestinal subtype. The mixed subtype variably expresses these markers. The prognosis of patients with intestinal subtype appears better than that of pancreaticobiliary and mixed subtypes. Accurate subtyping of ampullary carcinoma is clinically important to patient management and prognosis assessment.

Choriocarcinoma can be difficult to differentiate from other subtypes of testicular germ cell tumor and can occur unexpectedly in a distant, late metastasis. The aim of this investigation was to identify a marker superior to β-human chorionic gonadotropin (β-hCG) for choriocarcinoma. Sixty-two primary and metastatic testicular germ cell tumors (27 choriocarcinomas, 19 yolk sac tumors, 29 embryonal carcinomas, 28 seminomas, 22 teratomas, 3 epithelioid trophoblastic tumors [ETTs]) were analyzed for immunohistochemical expression of cytokeratin 7 (CK7), inhibin, p63, and β-hCG. All choriocarcinomas and ETTs were strongly positive for CK7, whereas seminomas were negative and 52% of embryonal carcinomas had weak reactivity. Eighty-four percent of yolk sac tumors and 59% of teratomas were CK7 positive. Eighty-nine percent of choriocarcinomas and 100% of ETTs were positive for inhibin, with reactivity highlighting syncytiotrophoblasts, whereas seminomas, embryonal carcinomas, yolk sac tumors, and teratomas were negative. Eighty-five percent of choriocarcinomas expressed p63, with staining mostly in mononucleated trophoblasts, whereas seminomas, embryonal carcinomas, and yolk sac tumors were negative. Teratomas expressed p63 in 32% of cases. β-hCG was reactive in 96% of choriocarcinomas, 33% of ETTs, 46% of seminomas, 54% of embryonal carcinomas, 47% of yolk sac tumors, and 32% of teratomas. β-hCG staining within other subtypes was more likely if choriocarcinoma was present elsewhere in the tumor (P = .0002). CK7 is a highly sensitive marker for choriocarcinoma and differentiates choriocarcinoma from seminoma and embryonal carcinoma. Inhibin and p63 are sensitive and specific for choriocarcinoma versus seminoma, embryonal carcinoma, and yolk sac tumor. To identify choriocarcinoma, CK7, inhibin, and p63 are superior to β-hCG., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Introduction: Although the immunohistochemical staining with cytokeratin 7 (CK7) is an adjuvant method for identifying various components of the intrahepatic biliary system, the expression of CK7 does not occur in hepatocytes. In the literature, some studies suggest that a group of cells having dual morphologic and immunophenotypic characteristics of bile duct epithelium and hepatocytes, referred to as progenitor stem cells, was stained positive with CK7., Materials and Methods: In this study, we examined a total of 219 cases diagnosed with autoimmune hepatitis, chronic hepatitis B, chronic hepatitis C, and primary biliary cholangitis between 2005 and 2017 in Uludağ University, Faculty of Medicine, Department of Medical Pathology., Results: The comparisons of AIH cases with HepB, HepC and PBC cases demonstrated that the immunoreactivity to CK7 was significantly higher in the AIH group (p < 0.005) compared to the groups of HepB and HepC, whereas no significant differences were found between the AIH and PBC groups., Conclusions: In our study, it was concluded that the immunoreactivity to CK7 could be used as an adjuvant treatment to the clinicopathologic assessment in distinguishing between the AIH cases and chronic viral hepatitis. However, since CK7 immunoreactive hepatocytes were widely detected also in patients with chronic viral hepatitis, and there was no statistically significant difference between the PBC and AIH cases, it has been established that the inclusion of CK7 immunoreactivity into the diagnostic histopathological criteria for AIH would not be convenient (Tab. 1, Fig. 1, Ref. 22).

Low-grade eosinophilic unclassified renal cell carcinoma is a rare kidney tumor recently described, not included in the WHO classification, which is very close to oncocytoma. It is unknown to most pathologists and clinicians. From a histopathological point of view, this tumor is composed of oncocytic cells arranged in a diffuse and solid pattern, without cell nests, that makes it possible to differentiate it from oncocytoma, and expresses cytokeratin 7 (CK7) heterogeneously. We report a case with a cranial vault metastasis, and present the features to differentiate this entity from oncocytoma. Furthemore, we discuss about unclassified renal cell carcinomas with oncocytic cells., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)

Renal mass lesions with a follicular architecture resembling atrophic kidney have been described, but their distinction from thyroid-like follicular carcinoma of the kidney remains controversial. We collected 8 cases of this purported "atrophic kidney"-like lesion to fully describe their clinical and histologic spectrum, their possible etiology, and to discuss their distinction from other renal neoplasms. Eight total cases were identified with patient ages ranging from 9 to 48 years (mean: 29 y; median: 28.5 y). Four patients were female and 4 were male. The tumors were unifocal and size ranged from 1.6 to 4.9 cm (mean: 3.4 cm; median: 3.4 cm). All 8 tumors had a remarkably similar histology. Each was enveloped by a smooth muscle rich capsule and had an overall low power "follicular" architecture. The luminal spaces of the "follicles" (or cysts) contained eosinophilic secretions and the lining epithelium was often flattened and atrophic, but some had more rounded cells with a distinctive hobnail arrangement. Many cysts contained discohesive round cells floating within the eosinophilic material, and some contained small intraluminal tufts with features of markedly atrophic glomeruli. Periodic acid-Schiff stains highlighted basement membrane material extending into these glomerular-like tufts, and some contained small distinct capillaries surrounded by endothelial cells, interspersed mesangial-like cells, and rare surrounding podocyte-like cells, providing additional evidence for glomerulocystic structures. Scattered calcifications were present within cysts (or within cyst walls) in varying numbers and were characterized by 2 types: psammoma body-like or more amorphous deposits. The tissue between cystic glomeruli contained predominantly small atrophic tubular structures, but collagenized stroma and smaller collapsed glomeruli were also present. The 2 tumors from the oldest 2 patients (48 and 39 y) had a more striking degree of stromal hyalinization. Immunohistochemically, the cyst lining cells had a predominant WT-positive/PAX-8 negative/CK7-negative phenotype, while tubules were typically WT-1 negative/PAX-8 positive/CK7-positive. Upon comparison to a control group of 10 kidneys containing incidental non-mass-forming glomerulocystic change, the morphologic features and immunophenotype were identical. To date, no patient has had any recurrence or aggressive clinical behavior based on follow status in 7 of 8 cases (follow-up range: 9 to 168 mo; median: 24 mo; mean: 40 mo). In summary, we describe the clinicopathologic features of 8 unique, benign "atrophic kidney"-like lesions that may simply represent a non-neoplastic form of organizing tubular atrophy and glomerulocystic change, and emphasize their distinction from thyroid-like follicular carcinoma of the kidney.

The favorable features of high-risk human papillomavirus (HPV) in the head and neck are limited to those harboring transcriptionally-active HPV, which occur predominantly in the oropharynx (OP). Factors rendering the OP susceptible to HPV oncogenesis are largely unexplored. The role of cytokeratin 7 (CK7) in predisposition to HPV and cancer in the cervix has been evaluated. However, its significance in the H&N is unknown. CK7 immunohistochemistry was performed on a tissue microarray cohort of OP and non-oropharyngeal (NOP) squamous cell carcinomas (SCC) with known clinical follow-up and HPV E6/7 mRNA status. Expression was graded based on the distribution (1 ≤ 33%, 2 = 33-66%, 3 ≥ 66%) and intensity (1 = weak, 2 = strong) with combined score of ≥ 2 considered positive. Survival analysis was performed. Seventy-four NOPSCCs and 204 OPSCCs were studied. HPV was positive in 2.7% of NOPSCCs and 70.9% of OPSCCs. CK7 was positive in 23.0% of OPSCCs and 14.8% of NOPSCCs (p = 0.2), and in 24.1% of HPV positive versus 17.2% of negative patients (p = 0.2). There was no correlation with age, race, gender, HPV status, histologic type, tumor subsite, treatment, stage, or co-morbidities, and CK7 expression was not significantly associated with overall or disease specific survival. In our series, CK7 is positive in ~ 25% of H&N SCCs, although usually only focally. While CK7 has been suspected to be overexpressed selectively in HPV-related OPSCCs due to their origination from tonsillar crypt epithelium, we did not find any significant difference by anatomic H&N subsite, nor by HPV status, for its expression and found no association with patient survival.

The literature records many examples of Merkel cell carcinoma (MCC) exhibiting aberrant immunohistochemical profiles. These can lead to diagnostic difficulty. The objectives of the current study were (1) to examine the immunohistochemical profile of different subsets of MCC to determine whether predictable subset-specific patterns exist and (2) to establish whether shared immunophenotypic patterns might reveal links between individual subsets, as demonstrated previously at a genetic level. In 52 cases of MCC, stratified by viral status and morphology, we studied 5 markers commonly used in the diagnostic evaluation of these tumors (CK20, CK7, chromogranin, neurofilament and TTF-1). Expression of these proteins was recorded as quantitative (H-scores) and absolute (positive vs negative) variables. In general, our data indicate that the "classical" or expected panel (CK20+, NF+, Chromo+, TTF-1, CK7-) is observed significantly more often in pure Merkel cell polyomavirus (MCPyV)-positive than in MCPyV-negative cases (78% vs 25%; P = .002). Neurofilament was less frequently encountered in MCPyV-negative than in MCPyV-positive tumors (66.7% vs 100%; P = .001) and expression of TTF-1 (37.5% vs 3.6%; P = .003) and CK7 (45.8 vs 14.3; P = .02) was more frequent. No significant immonophenotypic differences were observed between pure and combined MCPyV-negative tumors. Recognition of the more aberrant immunohistochemical profile of MCPyV-negative MCC should inform the diagnostic approach to this tumor. Moreover, the shared aberrant immunophenotype in pure and combined MCPyV-negative tumors supports a link between these entities and serves to separate them from MCPyV-positive tumors., (Copyright © 2018 Elsevier Inc. All rights reserved.)

The histologic differential diagnosis of perianal Paget disease includes malignant melanoma, pagetoid spread of squamous cell carcinoma, and secondary involvement by colorectal carcinoma. While consideration of these entities is useful when establishing a diagnosis, it does not apply when patients with Paget disease undergo surveillance for recurrent disease. Treatment of perianal Paget disease consists of a combination of surgical excision with skin grafts and topical chemotherapeutic agents that induce cytologic alterations in benign cells and simulate recurrent malignancy. To evaluate the therapy-related changes and possible diagnostic pitfalls in patients with Paget disease, we reviewed 412 posttreatment tissue samples from 3 women with primary perianal Paget disease who underwent wide excision, skin grafting, and topical 5-fluorouracil therapy. Biopsy samples from engrafted skin often displayed single and clustered cells with hyperchromatic nuclei dispersed in the deep epidermis. Similar cells were scattered throughout all levels of the epidermis in biopsy samples following topical chemotherapy. The abnormal cells were negative for cytokeratin 7 (CK7) and mucicarmine in both situations. Disease ultimately recurred in all patients; some Paget cells showed classic features with eosinophilic or mucinous cytoplasm and eccentric nuclei, whereas others were smaller with less conspicuous atypia. All Paget cells showed strong, membranous CK7 staining. In short, treatment of perianal Paget disease can elicit cytologic abnormalities in benign epithelial cells that simulate the cytologic features of recurrent disease, and can diminish the atypia of Paget cells. Immunohistochemical stains for CK7 can be helpful when evaluating surveillance samples from these patients.

Background: Clear cell papillary renal cell carcinoma (CCPRCC) is a new but rare tumor entity as listed in the World Health Organization 2016 renal tumor classification. Around 360 cases have been reported in the English literature to date, and only one tumor with sarcomatoid change was reported to develop distant metastasis. In the present study, we aim to review the clinical course and analyze the treatment outcome of CCPRCC in our institution., Methods: We retrospectively collected patients diagnosed with CCPRCC between January 2008 and September 2016 in our institute. The clinical features, pathology slides, and clinical outcomes were reviewed., Results: Twenty-five patients were collected during the study period, with a mean age at diagnosis of 62.8 years (range 35-85 years). Three patients developed the tumor in their native kidney following a kidney transplant, and three patients were diagnosed by needle biopsy before cryoablation therapy due to high surgical risk. The mean follow-up time was 49.7 months (range 12-119 months). During the follow-up period, all patients were alive without local recurrence or distant metastasis. All tumor specimens in our series expressed cytokeratin 7 (CK7) diffusely in immunohistochemistry staining. One patient was diagnosed with pT3a cN0M1, Fuhrman grade 3 CCPRCC with renal vein invasion and lung metastasis in 2010 on the basis of the histologic pattern and immunoreactivity for CK7. The clinical course was not compatible with any of the reported cases in the literature, so the kidney specimen was re-examined using whole-exome sequencing. The diagnosis was then revised to clear cell renal cell carcinoma., Conclusion: Our series confirmed that CCPRCC has an indolent clinical behavior. When the diagnosis is made in a high-grade renal tumor, it should be carefully re-confirmed using cytogenetic or genomic methods., (Copyright © 2018. Published by Elsevier Taiwan LLC.)

Objective: To investigate the clinicopathologic and molecular genetic features of secretory carcinoma of salivary gland (SCSG). Methods: Six cases of SCSG were collected from Zhejiang Provincial People ' s Hospital from January 2011 to March 2018. The clinical, histopathological and immunohistochemical features were analyzed and fluorescence in situ hybridization (FISH) was used to detect ETV6 gene rearrangement. Results: Four out of 6 tumors originated in the parotid gland and one of each in the minor salivary glands of soft palate and the buccal mucosa. Grossly, 4 cases were solid and 2 were partially cystic with maximum diameter ranging from 1.0 to 4.0 cm. Microscopically, 5 tumors showed typical features of low grade SCSG with tumor divided by thin fibrous septa into lobules composed of solid acinar, microcystic, follicular and papillary structures with abundant extracellular mucinous secretions. The tumor cells had cuolated or hobnail cytoplasm with low-grade nuclei and scarce mitoses. Perineural invasion was present in 1 case. The remaining tumor showed about 30% of the tumor areas with high-grade transformation characterized by proliferation of a distinct population of anaplastic cells arranged in irregular glandular, small nested and single cell patterns that were surrounded by desmoplastic stroma and invaded into surface mucosa with ulceration. Immunohistochemistry showed that all 6 tumors had diffuse and strong reactivities to S100 protein and cytokeratin 7, and 4 cases showed focal reactivity to gross cystic disease fluid protein 15 (GCDFP15), all were negative for discovered on gist 1 (DOG1), cytokeratin 20, p63 and calponin. High grade transformation cases were analysed, the high grade SCSG components showed a significantly increased Ki-67 index and cyclin D1 positive tumor cells compared to the conventional SCSG components. FISH analyses showed that 4 cases had ETV6 gene rearrangement. Eleven to seventy one months' follow-up showed no evidence of tumor recurrence nor metastasis. Conclusions: SCSG harbors characteristic genetic abnormalities with ETV6 gene rearrangement and typically shows a low grade morphology with occasionally, high grade transformation can be present.

We report a rare case of pulmonary enteric adenocarcinoma (PEA) exhibiting a immunohistochemical feature of CK7/CK20 double-negativity by evaluating the transformation zone between PEA and conventional pulmonary adenocarcinoma (CPA). A 75-year-old man was found to have a mass, 40 mm in diameter, in the right lower lobe on chest computed tomography, and underwent right lower lobectomy. Histologically, the tumor was composed of a PEA and CPA component. The dominant PEA component had medium to large complex glands with tall columnar cells with eosinophilic cytoplasm and brush-border. The CPA component comprised small to medium glands with cuboidal cells. Moreover, intermediate glands (INT), which had cuboidal to tall columnar cells, with morphological features between PEA and CPA, was also observed in the transformation area. Immunohistochemically, the PEA component was negative for CK7, CK20, and TTF-1, and positive for CDX2 and SATB2 (weak): the CPA component was negative for CK20, CDX2, and SATB2, and positive for CK7 and TTF-1: the INT were negative for SATB2, with intermingled positive signals for CK7, CK20, TTF-1, and CDX2. The final diagnosis was PEA based on the CPA component and not colorectal carcinoma. To distinguish CK7-negative PEA from metastatic colorectal carcinoma, careful examination for a CPA component is very useful along with clinical information. There are no reports that discuss about process of oncogenesis, de novo sequence or transformation from CPA of PEA. This is the first reported case of CK7/CK20 double-negative PEA, with analysis of the transformation zone between PEA and CPA components.

The authors report a case of an orbital metastasis from an occult breast carcinoma. A 66-year-old woman presented with a growing left orbital tumour. Orbital CT scan was consistent with lymphoma. However, ocular pathology revealed small neoplastic cells showing an 'indian file pattern' suggestive of metastatic carcinoma and immunohistochemistry was positive for CK7, CK CAM5.2 and oestrogen receptor. A systemic evaluation was then performed with mammogram, breast ultrasound and MRI considered normal. An exhaustive systemic evaluation revealed multiple bone lesions, a right axillary lymph node lesion, which presented the same pattern on pathology and immunohistochemistry, with no evidence of a primary tumour. A diagnosis of a metastatic lobular carcinoma of the breast (T0, N1, M1) was made and the patient was started on chemotherapy and adjuvant hormonal therapy., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

We report the case of a 15 years old teenage girl presenting with a primary amenorrhea and hypervirilisation symptoms. The clinical assessement found a 16cm wide heterogenous ovarian mass testosteronemia and alpha-foeto protein levels were increased. On gross exam the tumor was solid and cystic, multilocular containing serous and mucinous liquids. Microscopically, there was a sertoli cells rich solid area in which the cells had a trabecular and nested organization with Leydig cells between them and there was also a cystic area made of glandular structures lined with an intestinal muco-secreting epithelium. Next to these area, there were Sertoli cells and an oedematous stroma. The immunostaining showed that the Sertoli cells expressed, among others, the inhibine and the glands expressed the cytokeratins 7 and 20. A Sertoli and Leydig cells tumor of intermediate differentiation with heterologous elements diagnostic was made. This is a rare tumor, representing less than 0.5% of ovary tumors. Well differentiated tumors are not frequent. In one third of the cases, there are hypervirilisation symptoms, the imaging exams will serve to narrow the diagnosis and to do a full work-up to establish an extension. There are several histologic sub types caracterised by the existence of retiforms structures or heterologous elements. There are no specific immunostainings, this will only help to narrow the diagnosis and rule out some hypothesis. There are no guidelines for the management of the patients, indeed each center has its own practices. Those tumors have quite a good prognosis thanks to their early diagnosis at a stade where they are still confined to the ovary., (Copyright © 2018. Published by Elsevier Masson SAS.)

Cervical intraepithelial neoplasia (CIN) 2 is an equivocal diagnosis, with p16 immunohistochemical positivity currently recommended for diagnostic confirmation. Biomarkers characteristic of squamocolumnar junction cells were recently found to be positive in almost all CIN 2 and CIN 3. CIN 1 lesions which express squamocolumnar junction markers (in particular cytokeratin 7 [CK7]) are associated with a higher rate of subsequent high-grade squamous intraepithelial lesion, suggesting that CK7 may be a useful prognostic biomarker for CIN 1. We sought to determine the utility of CK7 as a prognostic biomarker in the setting of morphologic CIN 2, and to compare this to the utility of p16 in this setting. We performed CK7 immunohistochemical on 116 cases originally diagnosed as CIN 2. Of these, 68.1% were p16 and 90.5% were CK7. A total of 19.5% of patients had a subsequent diagnosis of CIN 3 on biopsy or excision; the index CIN 2 lesion was CK7 in all of these cases (sensitivity 100%) and p16 in all but 1 (21/22; sensitivity 95.5%). The specificity of p16 (37.4%) and CK7 (8.0%) for predicting subsequent CIN 3 were significantly different (P<0.001). While p16 expression was significantly associated with subsequent CIN 3 (P=0.002), CK7 expression was not (P=0.202). We conclude that CK7, unlike p16, is not useful as a prognostic biomarker in CIN 2. While it is still promising as a prognostic marker in CIN 1, additional studies are needed to determine optimal staining/interpretation criteria.

SATB2 is a sensitive marker for colorectal adenocarcinomas. No study has investigated its diagnostic utility in metastatic Krukenberg tumors (MKTs) of the ovary. Here we performed immunohistochemical staining SATB2 in 70 MKTs of various origins (stomach 27, colorectum 13, appendix 20 including 19 metastatic adenocarcinomas ex goblet cell carcinoids [AdexGCC] and 1 conventional poorly differentiated carcinoma with signet ring cells, breast 5, bladder 3, lung 2) to assess its diagnostic utility. We also compared SATB2 with CDX2, CK7, CK20, chromogranin, and synaptophysin in MKTs of gastric origin (MKTs-stomach), those of colorectal origin (MKTs-colorectum) and those due to appendiceal AdexGCCs (MKT-AdexGCCs) for their sensitivity and specificity to distinguish these tumors. SATB2 staining was seen in 1/27 (4%) MKTs-stomach (40% cells), 7/13 (54%) MKTs-colorectum (mean: 17% cells, median: 7%, range: 2% to 60%), and 19/19 (100%) of MKT-AdexGCCs (mean: 97% cells, median: 100%, range: 80% to 100%) (P<0.01 between any two). SATB2 staining was seen in 1/1 metastatic appendiceal poorly differentiated carcinoma with signet ring cells (5% cells), 1/3 MKTs of bladder origin (60% cells), 0/2 MKTs of pulmonary origin, and 1/5 MKTs of breast origin (10% cells). SATB2 staining was diffuse strong in MKT-AdexGCCs whereas in other MKTs it was focal and weak in the signet ring and nonsignet ring nonglandular cells and from focal weak to diffuse strong in well-formed glands. MKTs-stomach, MKTs-colorectum, and MKT-AdexGCCs showed no significant staining difference in CDX2 (100%, 100%, 100% cases, respectively; P=1.0), CK20 (96%, 100%, 100%, respectively; P=1.0), chromogranin (59%, 31%, 63%, respectively; P>0.05) or synaptophysin (59%, 63%, 84%, respectively; P>0.05) but they had significant difference in CK7 staining (93%, 8%, 42%, respectively; P<0.05). Among these 6 markers, SATB2 is the best one to distinguish MKT-AdexGCCs from MKTs-stomach (100% sensitivity, 96% specificity) and MKTs-colorectum (100% sensitivity and 100% specificity if staining more than 75% tumor cells as the cutoff). In distinguishing MKTs-stomach from MKTs-colorectum, SATB2 is not as good as CK7 which is the best marker. Our results indicate that SATB2 is a highly sensitive marker (100% sensitivity) for metastatic MKT-AdexGCCs with high specificity (100% specificity when showing strong staining in at least 75% cells) among MKTs. SATB2 is a useful marker for determining the primary sites of MKTs of the ovary.

Clear cell papillary renal cell carcinoma (CCPRCC) is a low-grade, indolent neoplasm with no reported cases of death from disease or metastasis. These lesions can show clinical, morphologic, and immunophenotypic overlap with several aggressive forms of renal cell carcinoma (RCC), including clear cell RCC, translocation RCC, and papillary RCC with cytoplasmic clearing. Given the difference in behavior, it is important to reliably separate these entities. We retrospectively reviewed 47 tumors from 45 patients with morphologic features of CCPRCC. All cases were stained against cytokeratin 7 (CK7), carbonic anhydrase IX (CAIX), and GATA3. Cases inconsistent with CCPRCC were reclassified. In addition, we stained tissue microarrays with 103 typical clear cell RCCs and 62 papillary RCCs, each in triplicate. Twenty-five cases were morphologically and immunophenotypically consistent with CCPRCC; all of them showed diffuse CK7 expression and cup-like reactivity with CAIX. Of these, 19 (76%) showed strong nuclear reactivity for GATA3. Although some non-CCPRCC neoplasms showed at least partial CK7/CAIX coexpression, none were immunopositive for GATA3. All background normal kidneys studied showed GATA3 expression in the distal tubules, collecting ducts, and retention cysts of the distal nephron. On follow-up, none of the patients with CCPRCC had recurrences or metastasis. Sensitivity and specificity for GATA3 staining in the diagnosis of CCPRCC were 76% and 100%, with positive and negative predictive values of 100% and 74%. In conclusion, GATA3 is specific and sensitive for CCPRCC and can be used for accurate distinction from its main mimickers. Coexpression of GATA3 and CK7 in most CCPRCC provides evidence of their origin from distal nephron., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Objective: The aim of this study was to evaluate p16, cytokeratin 7 (CK7), and Ki-67 immunoexpressions in low-grade squamous intraepithelial lesion (LSIL), looking for differences among cases that progress to high-grade squamous intraepithelial lesion, maintain LSIL, or regress., Materials and Methods: Sixty-six LSIL biopsies were studied. In the follow-up, a second biopsy showed 28.7% regression, 37.9% LSIL, and 33.4% progressed to high-grade squamous intraepithelial lesion. Immunostaining for these markers were performed in the first biopsy. A qualitative evaluation method was used, as well as histomorphometry, using ImageJ software. Pearson χ, Mann-Whitney, Kruskal-Wallis, and Fisher tests were used to compare the groups (P ≤ .05). A cutoff point was assessed through receiver operating characteristic curve positive cell ratio, for each marker, as progression predictors., Results: The mean age of patients with and without progression was 33 and 27 years (P = .006), respectively. The qualitative evaluation indicated a tendency of progression, but without statistical significance. However, through histomorphometry, the receiver operating characteristic curve analysis showed cutoff points of 0.396, 0.345, and 0.026 for p16, CK7, and Ki-67 ratios, respectively, as predictors of progression (P = .003, .03, and .002, respectively). In a logistic regression analysis, p16, CK7, and Ki-67 positive cell ratio showed a significant correlation with progression (P = .036, .012, and .006, respectively)., Conclusions: p16, CK7, and Ki-67 may represent useful biomarkers that can identify LSIL lesions that need particular attention.

Most cervical low-grade squamous intraepithelial lesions (LSILs) do not progress to high-grade squamous intraepithelial lesions (HSILs); however, reliable biomarkers that predict LSIL progression are lacking. We investigated the association of cytokeratin 7 (CK7), human papillomavirus-L1 capsid protein (HPV-L1), and koilocytosis with clinical outcomes of patients with LSIL. CK7, HPV-L1, Ki67, and p16-INK4A expression was determined in 72 cervical LSIL and 28 HSIL biopsy samples; koilocytosis was evaluated by reviewing biopsy slides. Fifty patients with LSIL received follow-up. CK7, HPV-L1, and koilocytosis were detected in 48.6%, 44.4%, and 52.0% of LSIL tissues and in 78.6%, 10.7%, and 64.3% of HSIL tissues, respectively. Lesion grade was correlated directly with CK7 expression (P=.007) and inversely with HPV-L1 expression (P=.004). CK7 expression in LSILs was correlated inversely with HPV-L1 expression and directly with p16-INK4A and Ki67 status. Furthermore, koilocytosis was significantly associated with HPV-L1 and p16-INK4A expression. Progression to cervical intraepithelial lesions of grades ≥2 occurred in 34% of cases. CK7 negativity and HPV-L1 positivity were significantly associated with lower HSIL progression rates. HPV-L1-positive and CK7-negative LSILs showed significantly lower progression rates compared with HPV-L1-negative and CK7-positive LSILs (6.3% v-positive cases showed a significantly lower progression rate (17.6%) compared with nonkoilocytic and HPV-L1-negative cases (50%). CK7-negative, HPV-L1-positive, and koilocytic LSILs showed a progression rate of 7.7%. Koilocytosis and p16-INK4A were not significantly associated with clinical outcomes. Hence, evaluating HPV-L1, CK7, and koilocytosis profiles combined may be more reliable for LSIL prognostication., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: Human papillomavirus (HPV)-related oropharyngeal squamous cell carcinoma (SCC) represents a distinct subgroup of head and neck tumors. We analyze the expression of cytokeratin 7, a junctional biomarker with a SEQIKA fragment, which stabilizes HPV-16 E7 transcripts, in oropharyngeal SCCs. Methods: Archived tumor specimens and epidemiologic data were collected from patients with oropharyngeal SCCs over 10 years. Briefly, DNA was extracted from tissue blocks, and HPV testing was carried out using SPF10 HPV PCR and INNO-LiPA HPV Genotyping. Immunohistochemical staining for CK7 and p16ink4a was performed on the Ventana BenchMark Ultra Immunostainer. Analysis was by light microscopy using the H -score. CK7 expression was correlated with epidemiologic data, p16ink4a positivity, and HPV status using SPSS. Results: CK7 expression was observed specifically and uniformly in the tonsillar crypt epithelium of normal tonsils and tumor specimens. There were 226 cases of oropharyngeal SCCs, with 70 demonstrating both HPV and p16 positivity. Of 216 cases evaluated for CK7, 106 demonstrated some positivity, whereas H -score > 60 was seen in 55 of these. CK7 H -score > 60 was significantly associated with tonsillar subsite and HPV and p16 positivity. Conclusions: An association between CK7 and HPV has been demonstrated. CK7-expressing tonsillar crypt cells potentially represent an oropharyngeal subsite susceptible to HPV-related SCC. Impact: Along with the cervix and anorectum, specific oropharyngeal expression of CK7 in a site predisposed to HPV-related tumors may suggest a role for CK7 in the pathogenesis of this subgroup of tumors. Further research is warranted to characterize the association between CK7 and HPV-related head and neck SCC. Cancer Epidemiol Biomarkers Prev; 26(5); 702-10. ©2017 AACR ., (©2017 American Association for Cancer Research.)

Renal oncocytoma and chromophobe renal cell carcinoma have been long recognized as distinct tumors; however, it remains unknown if uniform diagnostic criteria are used to distinguish these tumor types in practice. A survey was distributed to urologic pathologists regarding oncocytic tumors. Responses were received from 17 of 26 invitees. Histologically, more than 1 mitotic figure was regarded as most worrisome (n=10) or incompatible (n=6) with oncocytoma diagnosis. Interpretation of focal nuclear wrinkling, focal perinuclear clearing, and multinucleation depended on extent and did not necessarily exclude oncocytoma if minor. Staining techniques most commonly used included the following: cytokeratin 7 (94%), KIT (71%), vimentin (65%), colloidal iron (59%), CD10 (53%), and AMACR (41%). Rare cytokeratin 7-positive cells (≤5%) were regarded as most supportive of oncocytoma, although an extent excluding oncocytoma was not universal. Multiple chromosomal losses were most strongly supportive for chromophobe renal cell carcinoma diagnosis (65%). Less certainty was reported for chromosomal gain or a single loss. For tumors with mixed or inconclusive features, many participants use an intermediate diagnostic category (82%) that does not label the tumor as unequivocally benign or malignant, typically "oncocytic neoplasm" or "tumor" with comment. The term "hybrid tumor" was used variably in several scenarios. A slight majority (65%) report outright diagnosis of oncocytoma in needle biopsies. The morphologic, immunohistochemical, and genetic characteristics that define oncocytic renal tumors remain incompletely understood. Further studies correlating genetics, behavior, and histology are needed to define which tumors truly warrant classification as carcinomas for patient counseling and follow-up strategies., (Copyright © 2017 Elsevier Inc. All rights reserved.)

The authors present a case of Merkel cell carcinoma (MCC) with unique immunohistochemical staining characteristics. A 57-year-old woman presented with a firm 0.3 cm tan papule on her left nasal-labial fold that was reportedly increasing in size and bleeding. She had a history of multiple head and neck actinic keratoses, papillary thyroid carcinoma, and a family history of an uncle with melanoma. The clinical differential diagnosis was "non-melanoma skin cancer." Histological examination showed a markedly atypical-appearing basaloid neoplasm, present mostly in the dermis, with focal pagetoid spread into the epidermis. The cells showed hyperchromatic-staining nuclei, crowding, nuclear molding, and scant cytoplasm with atypical mitoses. The findings were consistent with a malignant tumor, highly suspicious for MCC. A pancytokeratin stain was strongly positive and showed perinuclear dot-like positivity. CK20 and CK7 stains were both negative. Synaptophysin was strongly positive, chromogranin was focally positive, CD56 was weakly positive, and neurofilament was positive in a perinuclear dot-like pattern. TTF-1, PAX5, S100, and Melan-A were negative, arguing against metastatic small cell carcinoma of lung or thyroid, B-cell lymphoma, or melanoma, respectively. Although the CK20/CK7 double negativity is very unusual, the staining characteristics of this case are most consistent with a primary cutaneous MCC. Up to 10%-15% of MCCs can be CK20 negative, and those cases are typically CK7 positive. This case is unique, as a CK20/CK7 double negative case has not been previously reported; however, the diagnosis can still be rendered based on the clinical, histological, and other immunohistochemical findings.