Search

Background Differentiated vulvar intraepithelial neoplasia (dVIN), the precursor lesion to human papillomavirus (HPV)-independent vulvar squamous cell carcinoma (VSCC), can be difficult to distinguish from vulvar inflammatory dermatoses. p53 has been suggested to be a useful biomarker for dVIN, but the percentage, intensity and patterns of staining have not been well characterized in dVIN and its histologic mimics. Method We studied p53 immunohistochemical staining patterns in 16 dVIN cases and 46 vulvar non-neoplastic squamous lesions (12 lichen sclerosus (LS); 7 lichen simplex chronicus (LSC); 3 lichen planus (LP); 6 psoriasis (PSO); 13 spongiotic dermatitis (SPO); 5 candidiasis (CAN)). dVIN cases were adjacent to a p16-negative invasive VSCC in resection specimens. Results All dVIN cases demonstrated null-type or moderate-strong uniform p53 staining in over 70% of basal cells, with moderate to strong continuous parabasal staining extending to two-thirds of the epidermis. This was in contrast to weak or weak-moderate patchy p53 staining in the majority of other lesions. Moderate-strong and increased basal p53 staining (≥70%) was also observed in a subset of lichen sclerosus (5/12, 42%), lichen planus (1/3, 33%) and spongiotic dermatitis (36%, 4/11), however in all categories, this was limited to the basal layer and any staining in the parabasal layers was patchy. Conclusion Strong and uniform p53 staining of basal cells, extending into the parabasal layers, and a complete absence of staining (null-type) is useful in distinguishing dVIN from other mimics in the vulva. p53 staining of lesser intensity or quantity, particularly basal-overexpression only, overlaps with vulvar inflammatory lesions.

AIMS The role of mismatch repair (MMR) testing has evolved from identifying Lynch syndrome patients to predicting response to immune checkpoint inhibitors. This has led to requests from clinicians to retest recurrences of MMR-proficient primary tumours in the hope that the recurrence may show a different MMR status and qualify the patient for treatment. We aimed to determine whether repeat testing is warranted. METHODS AND RESULTS We evaluated recurrent tumours (local recurrences or metastases) from 137 patients with MMR-proficient primary tumours of the gastrointestinal and gynaecological tracts. The local recurrences and metastases all occurred at least 30 days after resection of the primary tumour. We used a combination of a tissue microarray and whole slide staining to perform immunohistochemistry (IHC) for PMS2, MLH1, MSH2, and MSH6, and compared the results with the MMR status of the primary tumour. Three of 137 (2%) initially showed a discordant staining pattern. However, further investigation showed that these discordances were attributable to some of the known pitfalls associated with MMR IHC interpretation - post-radiotherapy loss of MSH6 expression and subclonal loss of MLH1 staining. We did not identify any cases with a genuine discordance in MMR status. CONCLUSION We conclude that repeat MMR IHC testing of recurrences is not warranted, as MMR status does not change relative to that of the primary tumour.

Recently, genetic analyses of primary mucinous ovarian tumours (MOT) have considerably enhanced our understanding of the biology of such neoplasms, supporting a progressive model of carcinogenesis from benign/borderline tumours to carcinomas. Nevertheless, the histogenesis of these neoplasms remains a subject of discussion and several cell types of origin have been proposed; a proportion of these tumours are associated with Brenner (transitional cell) tumours, therefore some are believed to be derived from metaplastic mucinous epithelium lining cystic transitional cell nests (Walthard rests).

INTRODUCTION:The most commonly mutated gene in vulvar squamous cell carcinoma (VSCC) is TP53 and its prognostic value, particularly in HPV-independent VSCC, is uncertain. In other tumors, p53 immunohistochemistry (IHC) is an excellent surrogate marker for TP53 mutations. In order to study this in VSCC, we assigned six p53-IHC patterns into two final classes: 'wildtype' or 'mutant'. We determined the performance and interobserver variability of this pattern-based p53-IHC approach.METHODS:Two experienced gynecologic pathologists scored the predefined p53-IHC patterns of 59 VSCC, independently and blinded for molecular data. Agreement was calculated by Cohen's kappa. All disagreements regarding p53-IHC patterns were resolved by a consensus meeting. After DNA isolation, the presence of pathogenic TP53 variants were determined by next-generation sequencing (NGS). Sensitivity, specificity, and accuracy of p53-IHC as a surrogate marker for TP53 mutation status were calculated.RESULTS:Initial p53-IHC pattern interpretation showed substantial agreement between both observers (k=0.71, pCONCLUSIONS:Pattern-based p53-IHC classification is highly reproducible amongst experienced gynecologic pathologists and accurately reflects TP53 mutations in VSCC. This approach to p53-IHC interpretation offers guidance and provides necessary clarity for resolving the proposed prognostic relevance of final p53-IHC class within HPV-independent VSCC.

Aims Gynandroblastoma is a rare ovarian sex cord-stromal tumour characterised by the presence of both male (Sertoli and/or Leydig cells) and female (granulosa cells) components. We investigated the mutational status of DICER1, FOXL2 and AKT1 genes at hot-spot regions that are known to be the key driving events in the development of Sertoli-Leydig cell tumour (SLCT), adult granulosa cell tumour (aGCT) and juvenile granulosa cell tumour (jGCT), respectively, to gain insights into the molecular pathogenesis of gynandroblastoma. Methods and results Sixteen cases of gynandroblastoma were studied. All contained SLCT or Sertoli cell tumour components. aGCT and jGCT components were identified in seven and 10 cases, respectively, with one presenting both components. Heterozygous hot-spot mutations in the RNase IIIb domain of DICER1 were discovered in three cases, including one case with heterologous mucinous elements, all of which were composed of moderately or poorly differentiated SLCT and jGCT components, and harboured the mutations in both histological components. None of the 16 cases displayed mutations at the p.C134W (c.402C→G) of FOXL2 or within the pleckstrin-homology domain of AKT1. All cases showed FOXL2 immunostaining in both male and female components. Conclusion DICER1 hot-spot mutation is the key-driving event in a subset of gynandroblastomas containing components of SLCT and jGCT. Gynandroblastomas composed of SLCT and jGCT may represent morphological variants of SLCT. The molecular basis of gynandroblastoma containing a component of aGCT is different from pure aGCT.

Aims Mammary-like adenocarcinoma (MLA) of the vulva is thought to be derived from vulvar mammary-like glands. The aim of this study was to characterize a series of MLAs by using an immunohistochemical algorithm that identifies the major molecular subtypes of breast cancer. Methods and results Seven cases of vulval MLA were stained for oestrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), Ki67, epidermal growth factor receptor (EGFR), cytokeratin (CK) 5, nestin, and inositol polyphosphate-4-phosphatase (INPP4b). Seventeen cases of vulval extramammary Paget disease (EMPD), seven with invasion, were studied for comparison. The median age of patients with MLA was 72 years. All tumours except one were early-stage tumours. On the basis of an immunohistochemical panel, three of seven tumours were classified as luminal B, two of seven as HER2-enriched, one of seven as luminal A, and one of seven as basal-like. ER was expressed in four of seven tumours, PR in three of seven, HER2 in three of seven, EGFR in two of seven, and CK5 in one of seven, and the Ki67 index was >15% in six of seven cases. Nestin and INPP4b were, respectively, negative and positive in all cases. Of the seven cases of invasive EMPD, two showed a luminal A profile, three a luminal B profile (two of three with HER2 amplification), one a HER2-enriched profile, and one a basal-like profile. Three of seven were HER2-amplified. Among the 10 cases of EMPD without invasion, seven showed a luminal A profile and three showed a luminal B profile (all HER2-amplified); no HER2-enriched or basal-like subtypes were identified. Conclusions Breast cancer subtyping can be applied to vulvar MLAs. All four intrinsic molecular subtypes are seen, with frequencies similar to those in breast carcinoma. Our results support the potential use of breast cancer molecular profiling algorithms to guide treatment for these cancers.

The era of molecular medicine has led to dramatically improved understanding of the genetic events that give rise to different types of cancers. In the case of gynaecological malignancies, this has resulted in distinct shifts in how these tumours are diagnosed in routine surgical pathology practice, with an increased emphasis on accurate subtype diagnosis. This has happened across all sites in the gynaecological tract and for most cell types, but in ways that are site-specific and may appear to be subtle, as in most instances the diagnostic terminology has not changed. For example, the diagnosis of clear cell carcinoma of the ovary is still in use, but the diagnostic criteria and clinical implications are different in 2017 from what they were in 2000. As a result, there can be a failure to appreciate how important these changes are and the resulting necessity of incorporating them into our daily practice. In this review we will describe changes in diagnostic surgical pathology occasioned by improved understanding of molecular events during pathogenesis, for cancers of ovary/tube, endometrium, cervix and vulva, and highlight how current practice differs from that of only a few years ago.

Aims Recent evidence indicates that weakly positive immunohistochemical staining of estrogen receptor (ER) is not reliably associated with a luminal subtype, with the majority re-classified as basal-like by gene expression profile. In this study we assessed the capacity of recently-identified immunohistochemical markers of basal-like subtype not dependent on ER status– positive expression of nestin or loss of inositol polyphosphate-4-phosphatase (INPP4b)– to discriminate intrinsic subtypes, focusing on clinically-problematic cases with weak ER positivity. Methods and Results Formalin-fixed paraffin embedded blocks, enriched for large proportions of ER negative and ER weakly positive breast cancers, were selected from two previous studies conducted in the period 2008-2013 and used for (1) RNA extraction for PAM50 intrinsic subtyping and (2) tissue microarray construction for immunohistochemical assessment of nestin and INPP4b. Fifty-eight cases were weakly-positive for ER (Allred 3-5), among which 28 (48%) were assigned as basal-like by PAM50 gene expression. In these 58 cases, nestin/INPP4b panel identified 23 basal-like cases with a positive predictive value of 87% (95%CI; 78%-95%) and excluded luminal subtype with a negative predictive value of 95% (95%CI; 88%-100%). Weakly positive ER patients assigned as basal-like by nestin/INPP4b definition demonstrated a median survival time of 45.8 months, significantly lower than 65 months among other ER weakly positive cases (p=0.012). Conclusions Immunohistochemical assessment of nestin and INPP4b provides an accurate, accessible and inexpensive tool to identify basal-like breast cancer subtype in the clinically problematic setting of weak ER positivity. This panel identifies poor prognosis patients who might need strong considerations for non-endocrine-based therapies. This article is protected by copyright. All rights reserved.

Aims Molecular investigation of small-cell carcinoma of the ovary, hypercalcaemic type (SCCOHT) has revealed that it is a monogenetic tumour characterized by alteration of SMARCA4 (BRG1), encoding a member of the switch/sucrose non-fermentable (SWI/SNF) chromatin remodelling complex. A large majority of cases show loss of expression of the corresponding SMARCA4/BRG1 protein. Furthermore, three cases of SCCOHT with retained SMARCA4 protein expression showed loss of SMARCB1/INI1 expression. The aim of this study was to assess the sensitivity and specificity of loss of SMARCA4 expression as a diagnostic test for SCCOHT. Methods and results We performed SMARCA4 and SMARCB1 staining in 245 tumours, many of which were potentially in the differential diagnosis of SCCOHT. We also stained 56 cases of SCCOHT for SMARCA4 and 37 of these for SMARCB1. Fifty-four of the SCCOHT cases showed complete absence of SMARCA4 expression. The two cases with retained expression showed molecular alteration of SMARCA4. Of the 217 other neoplasms with interpretable staining, all retained SMARCA4 expression. Although the majority showed diffuse, strong nuclear expression, a heterogeneous, typically weak staining pattern was present in 13% of cases. All 37 cases of SCCOHT tested and all other neoplasms, apart from three malignant rhabdoid tumours, showed retained nuclear SMARCB1 expression. Loss of SMARCA4 expression had a sensitivity of 96.55% and specificity of 100%. Conclusions Loss of SMARCA4 expression is sensitive and specific for SCCOHT. Although some mimics show heterogeneous expression, there is retention of nuclear staining in at least a part of the tumour; therefore, only complete loss of staining should be regarded as being supportive of SCCOHT.

Aims To characterize the histomorphological features of endometrial carcinomas (ECs) harbouring polymerase e (POLE) mutations. Methods and results Forty-three ECs with POLE mutations were compared with a cohort of 202 ECs. Most POLE-mutated ECs were endometrioid [34/43 (79%)]; the remaining tumours were mixed [6/43 (14%)], serous [2/43 (5%)], and clear cell [1/43 (2%)]. The endometrioid carcinomas were predominantly International Federation of Gynecology and Obstetrics grade 3 (27/43, 63%). The histotype distribution did not differ from that of control ECs (P = 0.69), but the grade of the EC was higher (P < 0.0005). Both nuclear grade and mitotic index were significantly higher in POLE-mutated ECs than in the comparison cohort. POLE-mutated ECs were associated with peritumoral lymphocytes and numerous tumour-infiltrating lymphocytes. Lymphovascular invasion was present in 20 of 43 tumours. Adjuvant radiotherapy and adjuvant chemotherapy would be offered in up to 80% and 40% of patients, respectively, on the basis of stage, grade, lymphovascular invasion, and histotype. Conclusions POLE-mutated ECs are typically of high grade, with prominent lymphocytic infiltration, but they are not sufficiently distinctive to allow accurate diagnosis based on routine haematoxylin and eosin staining. Even though POLE-mutated tumours are associated with an excellent prognosis, current guidelines for giving adjuvant treatment for EC result in most patients receiving adjuvant therapy.

Aims The available evidence indicates that most non-uterine high-grade serous carcinomas (HGSCs) arise from the fallopian tube (FT), but approaches to primary site assignment have not evolved to reflect this. The aim of this study was to assess the application of recently proposed criteria for site assignment. Methods and results One hundred and fifty-one HGSCs from four centres were reviewed retrospectively. Sixty-three of 80 (79%) chemonaive (CN) and 45 of 71 (68%) post-neoadjuvant chemotherapy (NACT) cases were assigned as FT primaries with the new criteria, whereas 58 of 80 (73%) and 45 of 71 (63%) were assigned as ovarian primaries with traditional criteria (P

Extra-uterine high-grade serous carcinoma (HGSC) accounts for most of the morbidity and mortality associated with ovarian carcinoma, and is one of the leading causes of cancer death in women. Until recently our understanding of HGSC was very limited compared to other common cancers, and it has only been during the last 15 years that we have learned how to diagnose this ovarian carcinoma histotype accurately. Since then, however, there has been rapid progress, with identification of a precursor lesion in the fallopian tube, development of prevention strategies for both those with inherited susceptibility (hereditary breast and ovarian cancer syndrome) and without the syndrome, and elucidation of the molecular events important in oncogenesis. This molecular understanding has led to new treatment strategies for HGSC, with the promise of more to come in the near future. In this review we focus on these recent changes, including diagnostic criteria/differential diagnosis, primary site assignment, precursor lesions and the molecular pathology of HGSC.

Aims The treatment of patients with tubo-ovarian high-grade serous carcinoma (HGSC) is increasingly based on diagnosis on small biopsy samples, and the first surgical sample is often taken post-chemotherapy. p53 and WT1 are important diagnostic markers for HGSC. The effect of neoadjuvant chemotherapy on p53 and WT1 expression has not been widely studied. We aimed to compare p53 and WT1 expression in paired pre-chemotherapy and post-chemotherapy samples of HGSC. Methods and results Immunohistochemistry (IHC) was carried out for p53 and WT1 on paired omental HGSC samples pre-chemotherapy and post-chemotherapy. p53 IHC was recorded as normal (wild-type) or abnormal (mutation-type), and was further classified as overexpression, complete absence, or cytoplasmic. WT1 IHC was classified as positive or negative. A subset of cases were further assessed for the extent of nuclear immunoreactivity of WT1 by use of the H-score. Fifty-seven paired samples were stained with p53. Fifty-six of 57 (98%) cases showed mutation-type p53 staining. Pre-chemotherapy and post-chemotherapy IHC results were concordant in 55 of 57 (96%) cases. For WT1, pre-chemotherapy and post-chemotherapy IHC results were concordant in 56 of 58 (97%) cases. In 23 paired WT1 cases, the mean post-treatment H-score decreased from 227 [range 20–298, standard deviation (SD) 64] to 151 (range 0–288, SD 78) (P = 0.0008). Conclusions Immunohistochemical expression of p53 (abnormal/mutation-type pattern) and WT1 in HGSC is almost universal and is largely concordant before and after chemotherapy. This finding underscores the reliability of these diagnostic markers in small samples and in surgical samples following neoadjuvant chemotherapy, with very few exceptions. A novel finding was the significant diminution in intensity of WT1 staining following chemotherapy.

The revised FIGO 2013 staging for carcinomas of the ovary, fallopian tube and peritoneum has introduced a single system for tumours originating at these sites. The system requires pathologists to assign a primary site (ovary, tube or peritoneum), but does not provide guidance to aid this assignment. This is particularly problematic in cases of advanced-stage (stage II or greater) high-grade serous carcinoma (HGSC), where there is commonly involvement of two or more sites by tumour, and practice among pathologists in determining where a tumour has arisen varies widely. This has significant implications for recording of tumour incidence and mortality, data collection by cancer registries, and entry into clinical trials. We propose guidelines for assigning the primary site of HGSC based on careful macroscopic and histological assessment. The use of these guidelines, in conjunction with the new FIGO staging system, is intended to act as an impetus to promote debate and provide a uniform and consistent approach in assigning primary tumour site which will facilitate comparison of data between centres.

Aims It is known that thyroid transcription factor-1 (TTF-1) is expressed in a small percentage of primary gynaecological adenocarcinomas. Following the observation of TTF-1 positivity in a number of endometrioid adenocarcinomas of the uterine corpus which behaved aggressively, we undertook immunohistochemical staining of a large series of endometrial adenocarcinomas of various types to investigate whether its expression is of prognostic significance. Methods and results TTF-1 was performed on tissue microarrays containing 102 low-grade (grades 1 or 2) endometrioid adenocarcinomas, 101 grade 3 endometrioid adenocarcinomas, 89 serous adenocarcinomas and 29 clear cell carcinomas. All categories of endometrial adenocarcinoma exhibited TTF-1 staining in a small subset of cases (2% low-grade endometrioid, 11% grade 3 endometrioid, 9% serous, 7% clear cell). TTF-1 was less frequently expressed in low-grade endometrioid adenocarcinomas compared to other subtypes. Endometrioid adenocarcinomas which expressed TTF-1 had a statistically significant worse prognosis with poorer disease-specific survival, and this was also statistically significant in the group of low-grade endometrioid adenocarcinomas. Conclusions Our study confirms that TTF-1 is expressed in a small, but not insignificant, proportion of endometrial adenocarcinomas. TTF-1 positivity in low-grade endometrioid adenocarcinomas is an indicator of poorer prognosis.

AIMS Vulvar squamous cell carcinoma (VSCC) can be subdivided by human papillomavirus (HPV) status into two clinicopathological entities. Studies on the prognostic significance of HPV in VSCC are discordant. METHODS AND RESULTS We performed a retrospective analysis of overall survival (OS), disease-specific survival (DSS) and progression-free survival (PFS) in 217 patients with VSCC. Cases were extracted from an era of more aggressive en-bloc radical dissections (1985-95) and more localized radical surgery through separate vulvar and groin excisions (1996-2005). p16 immunohistochemistry was used as a surrogate for HPV status. HPV status could be determined in 197 tumours, 118 HPV-independent and 79 HPV-associated tumours. Patients with HPV-associated tumours were younger (mean 58.8 versus 71.6 years for HPV-independent tumours, P < 0.0001) and more likely to have prior abnormal cervical cytology (41.1 versus 5.6% for HPV-independent tumours, P < 0.0001). In univariable analysis, patients with HPV-associated tumours had superior PFS [hazard ratio (HR): 0.37, 95% confidence interval (CI): 0.18-0.70], DSS (HR: 0.19, 95% CI: 0.08-0.41) and OS (HR: 0.35, 95% CI: 0.21-0.59). This was driven by worse outcomes (PFS, DSS and OS) for patients with HPV-independent tumours compared with HPV-associated tumours who underwent surgery after 1995. After adjusting for age and stage in multivariable analysis, patients with HPV-associated tumours showed superior PFS (HR: 0.25, 95% CI: 0.07-0.77) and DSS (HR: 0.21, 95% CI: 0.04-0.78). CONCLUSIONS VSCC can be stratified into two prognostically different diseases based on p16 immunostaining. HPV status was associated only with prognosis in the cohort that underwent surgery after 1995, suggesting that more conservative surgery may have led to worse outcomes for patients with HPV-independent tumours.

Aims To look for FOXL2 mutation in rare ovarian epithelial lesions showing stromal components with morphological features of adult granulosa cell tumour (AGCT). Methods and results We report the 402C→G FOXL2 mutation status in five epithelial ovarian lesions in women aged 45–77 years showing stromal proliferations that were morphologically indistinguishable from AGCT. The lesions were mucinous cystadenoma, mixed epithelial cystadenoma, endometriotic cyst, mucinous borderline tumour (intestinal type), and mucinous carcinoma. In one case, the AGCT component formed a discrete nodule, and in the others it was distributed within the septa and cyst walls. FOXL2 mutation was present in two cases and absent in three cases. One mutation-positive case showed an AGCT nodule abutting a mucinous borderline tumour, interpreted as a collision tumour. The other positive case had an AGCT component within the septa of a mucinous carcinoma, and both components are likely to be neoplastic. In the three cases without FOXL2 mutation, the stromal component most likely represents a non-neoplastic AGCT-like proliferation. Conclusions Areas typical of AGCT are rarely associated with epithelial ovarian lesions. These are heterogeneous and likely to be truly neoplastic in only a subset of cases. FOXL2 mutation testing may be useful in confirming a true neoplastic AGCT component.

Aims Dedifferentiated endometrial carcinoma (DDEC) is defined by the presence of an undifferentiated carcinoma together with an endometrioid carcinoma. Inactivation of SMARCA4 (BRG1) and inactivation of SMARCB1 (INI1) were recently described as potential mechanisms underlying the histological dedifferentiation. The aim of this study was to characterize the immunophenotypic features of DDECs, particularly in cases with prototypical histological and molecular features (BRG1/INI1 deficiency). Methods and results We evaluated PAX8, oestrogen receptor (ER) and p53 immunostaining in the endometrioid and the undifferentiated components of 20 BRG1/INI1-deficient DDECs and 15 BRG1/INI1-intact DDECs, and compared the results with those of 23 grade 3 endometrioid carcinomas. The differentiated endometrioid component was positive for PAX8 and/or ER in 19 of 20 BRG1/INI1-deficient DDECs, whereas the corresponding undifferentiated component of all 20 tumours showed a complete absence of PAX8 and ER staining. All except one of the BRG1/INI1-deficient tumours showed a wild-type p53 staining pattern. PAX8 and ER expression in the undifferentiated component was absent in 67% and 80% of BRG1/INI1-intact DDECs, respectively, whereas 47% of the BRG1/INI1-intact DDECs showed a mutated p53 staining pattern. In comparison, absent PAX8 expression and absent ER expression were each observed in the more solid area of 48% and 48% of grade 3 endometrioid carcinomas. Conclusions The consistent absence of PAX8 and ER expression in molecularly defined (BRG1/INI1-deficient) DDECs suggests that the loss of PAX8 and ER expression is a fundamental feature of dedifferentiation. The frequent findings of a mutated p53 staining pattern in BRG1/INI1-intact DDECs indicate that BRG1/INI1-intact DDECs may be biologically different from BRG1/INI1-deficient tumours.