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Nase kazuistika popisuje připad nekuřaka s generalizovaným plicnim adenokarcinomem s ALK translokaci. Po uvodnich dvou liniich chemoterapie byl ziskan přistup ke crizotinibu, na kterem brzy doslo ke vzniku drobne druhostranne leze, vyhodnocene jako metastaza v kontralateralni plici. Progresi v prave plici ale nezabranilo ani užiti ALK inhibitorů vyssi generace (ceritinib, alectinib, lorlatinib). Nasledně bylo prokazano, že přicinou teto progrese neni metastaticke onemocněni prave plice v podobě adenokarcinomu, ale přeměna ve skvamozni plicni karcinom s ALK translokaci. Timto sdělenim bychom proto radi upozornili na tuto eventualitu, kdy při atypickem radiologickem vývoji je na zvaženi rebiopsie progredujici leze.

The onset of routine use of the next generation sequencing (NGS) leads to discovery of new mutations in non-small cell lung cancer (NSCLC). In addition, comprehension of therapeutic potential of these genetic alterations in clinical practice is needed and required. Both, rare mutations and the therapeutic considerations they prompt, are dealt with in our case report describing a new fusion mutation of the fibroblast growth factor receptor (FGFR). Our case report describes a 45-year Caucasian female, non-smoker, with the tyrosine-protein kinase Met (cMET) skip 14 mutation and a newly described fibroblast growth factor receptor—cholinergic receptor, nicotinic, alpha 6 (FGFR-CHNRA6) fusion. The tumor in this patient showed aggressive growth and was resistant to all treatment modalities administered (including combination chemotherapy with bevacizumab, pemetrexed and nintedanib), with the exception of very short efficacy of crizotinib. The patient died 5 months after diagnosis. According to the published literature, a theoretical future solution could be to administer multidimensional targeted therapy simultaneously.

Pulmonary small cell carcinoma (SCLC) can be usually diagnosed based on the morphological evaluation of routine histological or cytological preparations. However, immunohistochemistry may be also necessary in problematic cases. Insulinoma-associated 1 (INSM1) has recently been reported as a highly sensitive and specific marker that displays positivity in ~90%-100% of poorly differentiated pulmonary neuroendocrine tumors. We compared diagnostic performance of INSM1 and previously reported composite marker CD56 + p16 + thyroid transcription factor-1 (TTF1) in the diagnosis of SCLC in small biopsy specimens and cytoblocks. The composite marker CD56 + p16 + TTF1 correctly classified 100% of SCLC cases, and its sensitivity was significantly higher than the sensitivity of INSM1. Among 100 SCLC cases, CD56, TTF1, and p16 each individually classified more specimens correctly than INSM1 (CD56: 84%, TTF1: 89%, p16: 95%, INSM1: 81%); the difference was statistically significant only for p16. INSM1 showed the lowest classification agreement between paired biopsy and cytoblock specimens (κ = 0.182), whereas CD56 and p16 displayed perfect agreement (κ = 1) and TTF1 showed moderate agreement (κ = 0.4). Although INSM1 is reportedly the most specific marker of SCLC, its sensitivity is not superior to p16 or composite marker CD56 + TTF1 + p16. Based on this study, we propose the following algorithm, which, in the appropriate clinical and histological context, may be useful in establishing the correct diagnosis of SCLC: First, INSM1 detection is performed, and if the result is negative, CD56 is added, followed successively by p16 and TTF1 if all previously applied markers are negative. This approach should detect most, if not all, SCLC cases, while successively trading specificity for sensitivity.

BACKGROUND Detection of tumor cells in lymph nodes (LNs) removed during the treatment of pulmonary tumor by radical surgery is limited by the possibilities of standard histopathological methods. The goal of this study was to obtain more accurate pTNM status by a more sensitive detection of micrometastases in LNs. METHODS A total of 885 LNs, an average of 13.8 LNs per patient, were removed during 64 surgeries. LNs from the same zone were pooled together as a group, five groups of LNs were examined in each patient. A total of 320 groups of LNs were examined. One-step nucleic acid amplification (OSNA) method was compared to standard histopathological examination with haematoxylin-eosin (H&E) staining and CK19 immunohistochemistry, specifically by an ultimate analysis of all intraoperatively removed LNs. RESULTS Identical results for H&E and OSNA examinations were recorded in 286 groups of LNs (89.4%). In total, positive examinations were recorded in 27 groups of LNs (8.4%) using the OSNA method, which were H&E negative. In seven groups of LNs (2.2%), the H&E examination was positive, while OSNA method produced negative results. CONCLUSIONS The OSNA examination led to a higher pTNM stage classification in 14 (21.9%) patients. The clinical significance remains the subject of follow-up research.

While erlotinib is primarily administered to patients with non-small cell lung cancer with sensitizing epidermal growth factor receptor (EGFR) mutations, it is also prescribed to patients with wild type (wt) EGFR in higher lines of treatment. However, there is no predictive marker for erlotinib efficacy in patients with EGFR wt. Certain immunohistochemical (IHC) parameters, including thyroid transcription factor 1 (TTF1) and p63, have been reported to indicate predictive power in patients with EGFR wt. The present study focused on retrospective data from the University Hospital in Pilsen using the TULUNG register. TTF1 and p63 expression data were extracted from the hospital information system and merged with registry data to calculate progression-free survival (PFS) and overall survival (OS) rates. A cohort of 345 patients with adenocarcinoma (ADC) or squamous cell carcinoma (SCC) exhibited similar erlotinib efficacies when TTF1 and p63 were ignored. However, significant differences were reported in PFS and OS rates of a subgroup of 126 patients where TTF1 and p63 parameters were known. In a univariate analysis, group A (ADC TTF1+/p63-) achieved PFS of 2.6 months, group B (SSC TTF1-/p63+) 1.9 months and group C (did not fit into groups A or B, i.e., ADC TTF1-/p63+ or SCC TTF1+/p63-) 1.4 months (P=0.006). Median OS was 14.2, 19.1 and 5.3 months for A, B and C, respectively (P=0.002). Furthermore, a multivariate analysis demonstrated IHC markers to be the only significant parameters for PFS and OS. Group C had a negative prognostic factor for PFS [hazard ratio (HR), 1.812; P=0.02] and OS (HR=2.367; P=0.01). In conclusion, patients with EGFR wt and lung carcinomas without TTF1 and p63 expression typical for ADC (TTF1+/p633-) or SCC (TTF1-/p63+) do not appear to be suitable candidates for erlotinib treatment.

Purpose solitary fibrous tumors (SFT) represent a heterogeneous group of primary pleural neoplasms with a low incidence rate and of which the biological origin, which consists of mesenchymal cells, is uncertain. Methods The authors present herewith a retrospective analysis of 22 patients with SFTs who were diagnosed and surgically treated between the years 2000-2015. The preoperative tumors were successfully verified morphologically by transthoracic core needle biopsy under CT control in 27.3% of patients. Surgical approaches were either posterolateral thoracotomy or videothoracoscopy. The follow-up median was 45 months (range 1-188 months). Results Twenty tumors were surgically removed radically, two tumors were found to be unresectable due to the considerable tumor size. From histological point of view 81.8% of tumors were SFT with low malignant potential, 18.2% of tumors with high malignant potential. Despite the radical extirpation of the SFT, it relapsed in two patients. Conclusion The gold standard of SFT treatment is radical surgical removal; however, patients at risk of recurrence require additional follow-ups. The results of adjuvant therapy in recurrent and malignant forms of SFTs are the subject of discussion and further study.

Background Patients with sensitive EGFR mutations are already being treated with first and second generation tyrosine kinase inhibitors (TKIs). However, resistance to these drugs occurs over time, and over half of all cases is caused by a mutation (T790M) in the EGFR kinase domain. Osimertinib offers a new treatment option that overcomes this problem. Unfortunately, resistance to this drug also develops after several months of treatment and is caused by another mutation (C797S) in EGFR. Case report Our case report provides evidence for the progressive development of EGFR-TKI resistance in a patient with a deletion of exon 19 in the EGFR gene. First, based on a mutation (T790M) identified after afatinib treatment and a subsequent mutation (C797S) mutation identified after osimertinib treatment. We mention overcoming this resistance (C797S) mutation by using 4th generation EGFR-TKI and other alternative procedures (chemotherapy, immunotherapy, and combinations of older EGFR-TKI generations). We also mention a rare case of peritoneal metastasis that occurred after previous treatment with osimertinib that we attempted to ameliorate by using erlotinib because the impaired condition of the patient did not allow treatment by chemotherapy. There are documented cases in which erlotinib has been successfully given to patients with peritoneal metastases and patients with the EGFR mutation C797S following progression to afatinib. This was not the case in our patient, probably because of the remaining EGFR mutation T790M. Conclusion In our case report, erlotinib did not show efficacy after progression to osimetinib. Nowadays, chemotherapy is the only possible treatment in patients with good a performance status. The next-generation of TKIs are undergoing promising developments.Key words: EGFR - deletion on exon 19 - mutation T790M - mutation C797S - afatinib - osimertinibSubmitted: 12. 9. 2017Accepted: 12. 10. 2017 This project was supported by grant AZV 17-30 748A. The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers.

A case is described of severe acute hepatitis in 47-year-old woman with chronic psoriasis and psoriatic arthritis treated with infliximab. Although clinical, serological and laboratory results were compatible with acute EBV hepatitis, it was difficult to differentiate between EBV infection and other non-infectious causes of hepatitis. The patient gradually developed chronic hepatitis with liver steatosis and efficient treatment with adalimumab had to be stopped. This case presents an uncommon complication that may arise from the use of biologic therapy and calls for caution in long-term management of psoriatic patients with internal comorbidities.

Attributing to their pathophysiological role and stability in biological samples, microRNAs (miRNAs) have the potential to become valuable predictive markers for non-small cell lung cancer (NSCLC). Samples of biopsy tissue constitute suitable material for miRNA profiling with the aim of predicting the effect of palliative chemotherapy. The present study group included 81 patients (74 males, 7 females, all smokers or former smokers) with the squamous cell carcinoma (SCC) histological subtype of NSCLC at a late stage (3B or 4). All patients received palliative chemotherapy based on platinum derivatives in combination with paclitaxel or gemcitabine. The expression of 17 selected miRNAs was measured by reverse transcription-quantitative polymerase chain reaction in tumor tissue macrodissected from formalin-fixed paraffin-embedded (FFPE) tissue samples. To predict the effect of palliative chemotherapy, the association between gene expression levels and overall survival (OS) time was analyzed. From the 17 miRNAs of interest, low expression levels of miR-342 and high expression levels of miR-34a and miR-224 were associated with a reduced OS time in subgroups of patients based on smoking status and treatment modality. Using cluster analysis, associations between combinations of miR-34a, −224 and −342 expression levels with patient survival were identified. The present study revealed that patients with the simultaneous high expression of miR-224 and −342 had a similar prognostic outcome to those with the low expression of miR-224 and −342, which was significantly reduced, compared with patients exhibiting high expression of either miR-224 or miR-342 with low expression of the other. We hypothesize that the effect of a particular miRNA is dependent on the expression level of other members of the miRNA network. This finding appears to complicate survival analyses based on individual miRNAs as markers. In conclusion, the present study provides evidence that specific miRNAs were associated with OS time, which may be candidate predictors for the effectiveness of palliative treatment in SCC lung cancer patients. This objective can be better achieved by combining more markers together than by using individual miRNAs.

Background Langerhans cell histiocytosis is a rare disease characterized by monoclonal proliferation and migration of special dendritic cells. This disease primarily affects bones, but occurs less frequently in other organ systems or may manifest as a multisystem disease. Case reports Extraoral and intraoral symptoms of Langerhans cell histiocytosis are described in a 13-month-old female and a 5-month-old male infant. Dermatitis was found on the scalp, abdomen, flexures and in intertrigineous areas in both patients. The intraoral examination of the 13-month-old infant showed premature eruption of all maxillary deciduous molars, loosening and significant damage of periodontal tissues (gingivitis with bleeding, swelling of palatal mucosa, periodontal pockets) resembling severe periodontitis. In the oral cavity of the 5-month-old predentate infant bilateral swellings of maxillary alveolar mucosa with deep ulcerations were seen. The oral and skin symptoms in both infants were indications for biopsy. Langerhans cell histiocytosis was confirmed histologically and immunohistochemically. Conclusion Oral findings in Langerhans cell histiocytosis may be the only clinical symptom of the disease; therefore the role of dentists in establishing diagnosis is very important.

Introduction: The surgical therapy of selected secondary pulmonary tumors, including both solitary and multiple or bilateral tumours, is currently a generally accepted therapeutic procedure demonstrably extend- ing the long term survival of these patients. Purpose: The purpose of the present study is a ten-year retrospective analysis of a group of patients who un- derwent surgery due to pulmonary metastases of various primary tumors. Methods: In 2000-2009, 87 patients (of which 44 were male with a median age of 64 years) with secondary pulmonary tumors underwent surgery at the departments of the authors of this study. Solitary metastases were found in 60 patients, multiple metastases in the remaining patients, while 13 patients had bilateral metastases. The median disease-free period from surgery of the primary tumor was 31 months. Results: In total, 74 unilateral and 13 bilateral surgeries were performed in one or two periods. The most com- mon type of surgery included anatomical pulmonary resections (32 procedures), wedge resections (29 proce- dures) and laser excisions (24 procedures). In total, the radical resection was performed in 156 metastases. Post-operative morbidity was 17.2 % with zero mortality. A proportion of 50.6 % of operated patients survived after resection of metastases with median survival of 39 months. The overall three-year and fi ve-year survivals in the group were 57 % and 38 %, respectively. A proportion of 35.6 % of patients live after resection of metas- tases without disease progression, and the median is 15 months. Conclusion: The achieved results confi rm the positive role of pulmonary metastasectomy in the therapy of dis- seminated cancer disease (Tab. 1, Fig. 5, Ref. 34). Full Text in PDF www.elis.sk. Hematogeneous pulmonary metastases are generally consid- ered as a sign of advanced generalization of malignant disease. Up to one third of malignant tumors have pulmonary metastases, and in most of them the lungs are even the fi rst site of dissemination. Nevertheless, in a signifi cant number of patients, the pulmonary affl iction is stopped or eliminated during the dissemination of metastases, and these patients may benefi t from radical resection of metastases (1, 2). Surgical therapy of the selected secondary pulmonary tumors, not only solitary but also multiple or bilateral, is today generally the accepted therapeutic procedure which de- monstrably extends long term survival of these patients with ac- ceptable peri-operative morbidity and mortality. The purpose of the following study is a retrospective analysis of a group of patients who underwent surgery due to pulmonary metastases of various primary tumors over a period of ten years. Material and methods

Vanek´s tumor (inflammatory fibroid polyp) is a rare benign lesion occurring throughout the digestive tract. Histologically, two patterns can be recognized. Classical Vanek´s tumor contains concentric formations of proliferating spindle cells which are CD34 positive. Atypical, inflammatory pseudotumor-like Vanek´s tumor lacks concentric formations and is CD34 negative. Recently, mutations in platelet-derived growth factor receptor alpha (PDGFRA) were reported in gastric and small intestinal Vanek´s tumors. In this study, KIT exons 9, 11, 13, and 17, PDGFRA exons 12, 14, and 18, and a part of exon 15 BRAF for point mutation V600E were screened in 23 cases of Vanek´s tumor, both classical (n = 16) and inflammatory pseudotumor-like (n = 7). No mutations in all analyzed exons of KIT and BRAF and in exon 14 of PDGFRA were detected. Six Vanek´s tumors harbored activating mutations in PDGFRA exons 12 (n = 5) and 18 (n = 1), respectively: S566_E571delinsK (n = 1), S566_E571delinsR (n = 4), and D842 del (n = 1). The mutations were detected in the classical (n = 5), as well as inflammatory pseudotumor-like (n = 1) Vanek´s tumors. The results of this study suggest that the two morphological patterns of Vanek´s tumor more probably represent only variants of one type of tumor than two different lesions. Furthermore, BRAF mutations were not shown to drive growth of PDGFRA wild-type Vanek´s tumors.

We report a patient with multiple trichoepitheliomas whose biopsy material also demonstrated a range of other neoplasms with follicular differentiation, including small nodular trichoblastoma, small nodular basal cell carcinoma (BCC), and areas resembling infundibulocystic BCC/basaloid follicular hamartoma. These were all intimately associated with otherwise typical trichoepitheliomas that dominated the microscopic appearances. Peripheral blood and tumor tissues of the patient and his 2 daughters, who apparently had a milder phenotype, were studied for alterations in the CYLD and PTCH genes, but mutations or loss of heterozygosity was not found in either gene. The occurrence of multiple follicular neoplasms within a single lesion adds evidence that, although in most cases BCC and trichoblastoma are distinct lesions, the 2 neoplasms do encompass a morphological spectrum of follicular differentiation, which is probably more overtly expressed in syndromic patients.

SUMMARY We report 5 patients with cellular ovarian fibromas, which contained heavy depositions of hyaline globules, a remarkable and very conspicuous histologic feature of all tumors. The hyaline globules ranged in size from 1 to 25 microm. Some cells were stuffed with myriads of small hyaline globules 1 to 3 microm in size, whereas in the other cells the globules were up to 25 microm in size. The hyaline globules were stained with periodic acid-Schiff, and were mucicarmine and Alcian blue negative. These hyaline globules were present, at least in small numbers, in all 100 hematoxylin and eosin slides reviewed from all 5 cases in this series. Often the cells containing the hyaline globules showed a signet-ring appearance in the more compact cellular areas. All the tumors in our series appear to have a benign course. The patients were without signs of recurrence and without metastasis 1, 2, 3, and 6 years after the excision of the neoplasms. Follow-up in one of the patients was not available. The distinction of the ovarian fibromas with hyaline globules from the Krukenberg tumors and yolk sac tumor is discussed in the paper.

The authors present a series of 5 cases of cutaneous sebaceous neoplasms having "benign" architectural features (symmetry, sharp circumscription, smooth borders, pseudoencapsulation) but which simultaneously displayed atypical cytology including abnormal mitoses, high mitotic rates, and moderate-to-striking pleomorphism including bizarre cells. The patients included 4 females and 1 male, ranging in age at diagnosis from 49 to 72 years. All presented with a small solitary nodule (6-9 mm) on the forehead (2), chest wall (1), occiput (1), and shoulder (1). The lesions were surgically excised. There were no recurrences on follow-up ranging from 16 to 148 months (average 77 months). In none of the patients was there a history of internal malignancy before or after diagnosis of the cutaneous neoplasms. Of 3 tumors assessed immunohistochemically for the expression of DNA mismatch repair gene proteins, only one showed loss of MLH1 expression. This was the only tumor to contain numerous tumor-infiltrating lymphocytes. Our report emphasizes the existence of rare sebaceous tumors that, despite a deceptively bland architectural appearance, discordantly exhibit a range of atypical cytological features more characteristic of either low-grade or even high-grade carcinomas. Whether such tumors should be classified as sebaceomas with atypia or sebaceous carcinomas is unclear at present. Further studies are needed to confirm their seemingly benign course as identified in this report, as are further investigations to clarify their association with Muir-Torre syndrome.

Background Several histopathologic variants of cutaneous leiomyomas have been recognized. In our consultation dermatopathology practice, we encountered a variant of cutaneous leiomyoma which, to our knowledge, has not been reported. Objective We report 3 cases of vascular leiomyomas, all of them manifesting prominent intratumoral calcifications dominating over the residuum of the tumors and occurring on the acral sites. Methods We conducted a clinicopathological and immunohistochemical study, which is complemented by a literature review. Results All 3 patients were women ranging in age from 57 to 72 years. Each presented clinically with a slowly growing, firm mass. The lesion was painful in two cases. None of the patients had renal disease or endocrine abnormalities. Microscopically, the lesions were a well-circumscribed, non-encapsulated neoplasm composed of mature smooth muscle cells and vascular pattern, which was inconspicuous, but focally dilated blood vessels were present. In all cases, prominent calcifications were present. Immunohistochemically the spindle cells were positive for α-smooth muscle actin. Limitations This study utilizes tissue specimens that all came as consultations; therefore, some inherent selection bias exists. Conclusion Acral calcified vascular leiomyoma is a rare clinicopathological variant of leiomyoma which has predilection for acral sites and shows massive calcifications prevailing over the tumor itself.

The authors report a case of basaloid carcinoma involving the anus and rectum of a 57-year-old woman. Microscopically, the tumor showed unusual morphologic features strongly resembling a spiradenocylindroma because it consisted, in most parts, of basaloid cell nodules arranged in a jigsaw-puzzle fashion containing or surrounded by eosinophilic basal membrane material; in addition, there were intratumoral lymphocytes. The overlying squamous epithelium manifested dysplastic changes compatible with in situ squamous carcinoma that gradually became invasive and blended with basaloid cell islands; additionally, there were koilocytes in the squamous epithelium. A molecular biology study identified HPV-16 in the lesional tissue. Analysis of the CYLD gene did not prove any mutation.

Although prominent vascular proliferation is a known feature of various neuroendocrine tumors, it has not been systematically studied in Merkel cell carcinoma (MCC) of the skin. The purpose of this study was to fully characterize the light microscopic, immunohistochemical, and ultrastructural features of vascular changes associated with MCC and to determine their frequency and differential diagnostic implications. Additionally, the presence of human herpesvirus 8 DNA in the lesional tissue was investigated. Of 92 studied cases of MCC, 18 cases (20%) were found to exhibit foci of prominent vascular changes which were classified into the following 6 patterns: pericyte hyperplasia, pyogenic granuloma-like, hemangioendothelioma-like, epithelioid hemangioma-like, peliosis-like, and follicular dendritic cell tumor-like pattern. In addition, Azzopardi phenomenon was observed. These changes occurred singly or in combination. Human herpesvirus 8 DNA was identified by polymerase chain reaction in none of the 18 cases. It is concluded that prominent vascular proliferations may be seen in 20% of MCC, and thereby, MCC resembles neuroendocrine tumors in other organs. When unduly prominent and encountered in a limited biopsy specimen, vascular alterations may represent a potential diagnostic pitfall, but, on the other hand, they themselves may serve as a clue to the correct diagnosis. Human herpesvirus 8 does not play a role in angiogenesis in MCC.

Tubular adenoma (TA) and syringocystadenoma papilliferum (SCAP) may show histopathological overlap, with some lesions having features of both neoplasms (SCAP + TA). TA has been recently suggested to represent a carcinoma. Four observers blindly assessed 67 cases of TA, SCAP, and their lookalikes (poroma, apocrine adenoma, apocrine carcinoma; all lesions focally featuring a pseudopapillary pattern), and classified the lesions into one of four categories: (1) TA, (2) SCAP, (3) SCAP + TA, and (4) others. Lesions were also classified as benign or malignant. In only 29 cases was there unanimous agreement among the four observers, who classified 22 lesions as TA, three as SCAP, and four cases as others. Of the 38 cases where there was interobserver diagnostic variation, in 30, the diagnosis varied between TA or SCAP or SCAP + TA; the remainder fell in the others category. Analysis of the factors leading to interobserver variability indicated that diagnostic problems occurred when there were any of the following: epidermal acanthosis, papillomatosis, connection of the neoplastic tubules to the overlying epidermis and/or follicular infundibula, and plasma cell infiltration. These features accounted for the morphological overlap between TA and SCAP. All observers agreed that the lesions were benign; the only apocrine carcinoma included was recognized as such by all observers. From the study, it was concluded that TA may arise in the deep dermis without any epidermal connection, or, in other cases, it may be more superficially located with or without an epidermal connection. It may be reasonably inferred that, possibly as a response to infection, there may be accompanying plasma cells and variable acanthosis and papillomatosis, such that the appearances are those of "pure" SCAP, or lesions may have features "intermediate" or overlapping between TA and SCAP.

Pleomorphic hyalinizing angiectatic tumor (PHAT) of the soft tissue is a rare distinctive tumor listed as a benign neoplasm in the new World Health Organization classification. It may recur and most reported recurrent tumors retained the typical morphological appearance of PHAT; rare tumors recurred with the appearance of a sarcoma. Reported herein is an additional example of recurrent PHAT, but in contrast to the previously described cases the present tumor morphologically qualified as a sarcoma from the very beginning; it recurred as a high-grade myxofibrosarcoma. A 76-year-old woman presented with a solitary subcutaneous tumor in the axilla that was surgically removed. Seven months later, the patient experienced a local recurrence. Microscopically, the typical features of PHAT were identified in the initial lesion, namely hyalinized, fibrin-containing vessels and pleomorphic stromal cells; there were areas of hemorrhage and necrosis. Additionally, peripherally located areas of the tumor manifested highly pleomorphic cells with frequent atypical mitoses, producing a sarcomatous appearance. The mitotic index in the sarcomatous part was 1/10 high-power fields (HPF). Hyalinized, fibrin-containing vessels were absent in these sarcomatous areas, and the stroma was myxoid. The recurrent lesion was composed of large highly pleomorphic oval, round, spindled or bizarre cells with a high mitotic rate, ranging from 3/10 HPF to 7/10 HPF. The neoplastic cells were arranged haphazardly in a myxoid matrix. Hyalinized, fibrin-containing vessels typical for PHAT were absent. PHAT may be more aggressive than previously thought, and PHAT may encompass a morphological spectrum of the lesion ranging from benign to malignant.

Background Abdominal desmoid tumor is one of the forms of deep (musculoaponeurotic) fibromatosis. It occurs more often as a desmoid tumor in the abdominal wall, less often in various intra-abdominal locations. In this work, we performed retrospective study concerning diagnostic problems of this disease with the use of imaging techniques. Method Four patients (three females and one male) were examined by postcontrast CT (computed tomography) and one of them also by MR (magnetic resonance). All findings were correlated with the operational findings and histologic examination. Results The findings were typical only in the case with the lesion located in the abdominal wall, three described cases of the intra-abdominal desmoid provided a broad range of differentially diagnostic possibilities (metastases, GIT tumors, lymphomas, etc.). In particular, the findings in infiltrative processes in intra-abdominal location and retroperitoneal involvement were less typical. Ultimately, the histological findings were decisive. Conclusion The possibility of the occurrence of intra-abdominal desmoid tumor must be considered particularly in younger individuals with rapidly growing tumorous process, which does not immediately arise from the surrounding organs (digestive tract, internal genitalia, etc.), and is located in the abdominal wall or in the abdominal cavity.

A case is described of severe acute hepatitis in 47-year-old woman with chronic psoriasis and psoriatic arthritis treated with infliximab. Although clinical, serological and laboratory results were compatible with acute EBV hepatitis, it was difficult to differentiate between EBV infection and other non-infectious causes of hepatitis. The patient gradually developed chronic hepatitis with liver steatosis and efficient treatment with adalimumab had to be stopped. This case presents an uncommon complication that may arise from the use of biologic therapy and calls for caution in long-term management of psoriatic patients with internal comorbidities.

We present a series of 15 cases of cutaneous lymphoma and pseudolymphoma with dual lineage rearrangement identified among approximately 1200 cases of cutaneous lymphoproliferative disorders assessed in our 4 institutions during the last 8 years in which the results of both T-cell receptor and immunoglobulin heavy chain rearrangement investigations were available. On the basis of the clinicopathologic information, the cases were retrospectively subdivided into 2 categories: (1) cases with definite features of cutaneous lymphoma or pseudolymphoma (n = 11) and (2) cases with unclassifiable disease (n = 4). The detection of dual genotype in the first group did not influence the final diagnosis; 7 cases represented cutaneous B-cell lymphomas, 3 pseudolymphomas, and 1 case lymphomatoid papulosis. The presence of monoclonal T-cell receptor-gene rearrangements in these cases may be explained either by monoclonal or oligoclonal expansion of exuberant T cells (or B cells in case of lymphomatoid papulosis) or by lineage infidelity. Three patients with unclassifiable disease had several clinical and histopathologic features in common. They were elderly, presented with solitary lesions, were in good general health and histopathologically demonstrated a dense multinodular infiltrate containing approximately an equal number of T and B cells and a high number of histiocytes forming granulomas, with prominent granulomatous features in 2 cases. B cells were either scattered with the infiltrate or formed collections vaguely resembling follicles; Reed-Sternberg-like cells were seen in 2 cases. B cells showed expression neither of immunoglobulin light chain. The T-cell component was represented mainly by small, well-differentiated lymphocytes or slightly pleomorphic cells, with some medium-sized convoluted cells. Epstein-Barr virus was not detected by polymerase chain reaction. The exact classification of these cases is unknown; they differ histopathologically from previously published cases of bigenotypic cutaneous lymphomas. They may merely represent a growth or reactive pattern, but, on the other hand, may be low-grade lymphomas. If so, they may be histopathologically related to cutaneous Hodgkin disease, T-cell/histiocyte-rich large B-cell lymphoma, or composite lymphomas. Further reports are needed to identify these lesions to clarify their nature and biologic potential.

The conjoint occurrence of follicular, sebaceous, or apocrine differentiations in a cutaneous adnexal neoplasm is a known event, more often encountered in benign neoplasms, whereas reports of cutaneous malignant adnexal tumors with bilineage or trilineage differentiation are few. A new case of a cutaneous malignant adnexal neoplasm with multidirectional differentiation is reported here. A 57-year-old woman presented with a long-standing, slowly growing, asymptomatic solitary tumor the size of a large nut in the coccygeal area, which was surgically excised. Ten years after the surgery, there was no evidence of recurrence or metastasis. Microscopically, the neoplasm was located in the dermis with focal extension into the subcutis. It was asymmetric, horizontally oriented, and mostly composed of small nodules that varied in shape from round and oval aggregations to elongated strands and irregular islands; the nodules were either clustered, formed a jigsaw puzzle-like pattern or were dispersed. The nodules were composed of small basaloid cells sometimes intermixed with larger cells with ample cytoplasm forming glandular structures. Rare nodules resembled elements seen in a spiradenoma by containing scattered lymphocytes and globules of hyalinized eosinophilic basal membrane material. The stroma was paucicellular, but focally it resembled that seen in perifollicular mesenchyme. Mitotic figures, including abnormal ones, were infrequent, but mild nuclear pleomorphism, nuclear crowding, and individual cell necrosis were easily appreciable in both small basaloid cells and cells with clear cytoplasm. Perineural invasion was apparent. We classified this tumor as a well-differentiated adnexal carcinoma demonstrating combined follicular and apocrine differentiation. It differs from previously published cases of malignant adnexal tumors with multidirectional differentiation and further exemplifies the spectrum of diversity encountered in malignant proliferations with differentiation toward the folliculosebaceous-apocrine unit.

Mullerianosis of the urinary bladder is a very rare and morphologically complex tumor-like lesion. It is composed of several types of mullerian-type lesions, including endometriosis, endocervicosis, and endosalpingiosis. This disease occurs in women of the reproductive age group. In the pathogenesis, implantative and metaplastic origins have been suggested, and they are still under discussion. In the present report, a rare case of this lesion in a 41-year-old woman is described. The bladder contained, in addition to typical mullerianosis, glandular cystitis with focal intestinal metaplasia. An interesting and, to our knowledge, hitherto unreported feature was a rare continuity between the glands of mullerianosis and glands of glandular cystitis. The histologic and immunohistochemical findings in the present case support strongly the metaplastic origin of mullerianosis.

The main controversies regarding tubular apocrine adenoma and papillary eccrine adenoma are whether they are two distinct entities or are the very same tumor, and if so, which lineage of differentiation (apocrine versus eccrine) it pursues. We report two cases of tubular adenoma with follicular and, in one case, additionally, sebaceous differentiation. The features in both cases indicated apocrine differentiation of the tubular component. One patient was a 60-year-old woman with a 1-year history of a solitary nodule on the scalp. The other patient was a 48-year-old woman with a solitary nodule of unknown duration located on the back. In both patients, the tumors were surgically removed. The patients were alive and well 2.5 and 2 years after surgery, respectively. The histologic features that both cases had in common included the combination of a tubular adenoma, foci of follicular differentiation, and areas of immature squamous metaplasia. In case 1, follicular differentiation was seen in the form of strands of basaloid cells surrounded by a stroma resembling the embryonic perifollicular sheath. Some aggregates of basaloid cells were juxtaposed with small collections of plump fibroblasts, imparting a resemblance to rudimentary follicular germs associated with follicular papillae. Many minute lumens surrounded by more eosinophilic cells were seen within the strands. In case 2, follicular differentiation was seen as several infundibulocystic structures surrounded by isthmic epithelium housing scattered mature sebocytes. In addition, there were areas reminiscent of desmoplastic trichoepithelioma (columnar trichoblastoma). In both cases, the areas with immature squamous metaplasia were represented by solid nodules that were mostly devoid of lumens and a peripheral basal/myoepithelial cell layer. In conclusion, these two cases of cutaneous tubular adenoma with accompanying follicular and sebaceous differentiation give further support to the proposition that the majority of these neoplasms have apocrine differentiation. Rare cases occurring in the sites normally devoid of apocrine glands may represent the eccrine counterpart.

This study characterizes the clinicopathological spectrum of lymphoproliferations involving the breast nipple and/or areola. Morphologic, immunohistochemical, molecular-genetic, and clinical features of 58 specimens from 56 patients were analyzed. They were re-diagnosed as cutaneous lymphoid hyperplasia (CLH, n = 44); other benign lymphoid infiltrates (OBLI, n = 8); peripheral T-cell lymphoma, not otherwise specified (n = 1); cases with overlapping features of CLH and B-cell lymphoma (n = 3), one of them composed of spindle cells. Cutaneous lymphoid hyperplasia infiltrates were dense, composed mainly of B cells forming follicles with germinal centers (GC). Cutaneous lymphoid hyperplasia frequently showed features suggesting a malignancy as coalescing follicles with non-polarized germinal centers lacking mantle zones, and smudged infiltrates of lymphoid cells spreading into collagen (often as "Indian files"), smooth muscle, vessel walls, and nerve sheaths. Only two cutaneous lymphoid hyperplasias recurred; otherwise all patients are without disease (mean follow-up 62 months). Monoclonal rearrangement of immunoglobulin heavy chain gene was detected in five, and of T-cell receptor gamma gene in two cutaneous lymphoid hyperplasias using polymerase chain reaction (PCR), but the patients fared well too. In 47% of cases Borrelia burgdorferi was detected by polymerase chain reaction and/or serology, of which one was monoclonal. We conclude that cutaneous lymphoid hyperplasia is the most common lymphoproliferation of the breast nipple, rarely recognized clinically, and often overdiagnosed histologically as lymphoma.

Pseudoangiomatous stromal hyperplasia (PASH), first reported in 1986, is nowadays a well-recognized change in the breast. We present three cases of lesions involving anogenital mammary-like glands demonstrating this feature. All patients were females (ages, 42, 43, and 53 years). Each presented with a solitary, 1.5- to 2-cm asymptomatic nodule. Locations included the perianal area, perineum, and labium majus. Histopathologically, one lesion was classified as low-grade phyllodes tumor, another as fibroadenoma, and in the remaining case PASH was found in the background of mild hyperplasia of anogenital mammary-like glands and substantial lipomatous metaplasia. In all lesions, PASH had an identical appearance to that in the breast, that is open, slit-like, often anastomosing channels devoid of erythrocytes and lined by discontinuous, often attenuated, inconspicuous cells without atypia or mitotic activity set in a hyalinized collagenous stroma. Quantitatively, PASH ranged in the above cases, forming a relatively small focus in the fibroadenoma and being quite extensive in the remaining two cases. In the phyllodes tumor, PASH areas exhibited focal hypercellularity and presence of myoid cells. In none of the cases were there cells with intranuclear inclusions or multinucleated cells. The lesions were surgically excised. Two patients with follow-up were disease-free at one and three years after the operation. As to our knowledge, PASH has not been previously described in the anogenital area, this feature seems to have been either overlooked or is genuinely rare in this location. It may occur in a preexisting lesion of anogenital mammary-like glands or may apparently by itself produce a clinically detectable lesion. The clinicopathologic features of PASH in the anogenital area seem to be identical to those in the breast.

This report emphasizes a carcinoid-like pattern, a previously unrecognized feature in cutaneous sebaceous neoplasms. We report 7 patients with sebaceous tumors in which neoplastic cells were arranged in a trabecular and ribbon-like pattern or formed rosettes/pseudorosettes. The cases included 6 men and 1 woman, with their ages at the diagnosis ranging from 43 to 87 years (median age, 59). All patients presented with a solitary lesion. Locations were the scalp (n = 6) and forearm (n = 1). The carcinoid-like arrangement of neoplastic cells was the sole pattern in 4 cases, and in 3 cases the so-called labyrinthine/sinusoidal and/or rippled patterns were seen in addition. Sebaceous differentiation in the form of mature sebocytes varied from almost none to approximately 10%. Although the neoplasm appeared benign architecturally, the presence of cytologic atypia qualified 2 tumors as low-grade carcinomas. Four lesions represented sebaceomas, and in 1 case microscopic delineation between a carcinoma and sebaceoma was difficult. No neuroendocrine differentiation was demonstrated immunohistochemically, histochemically, and ultrastructurally. Electron microscopic examination performed in 1 case of carcinoma revealed lipid vacuoles in a minority of cells. There were no membrane-bound neuroendocrine granules. Rare cells contained peculiar large helioid inclusions. We conclude that the carcinoid-like pattern is another distinctive pattern indicative of sebaceous neoplasms. This pattern seems to be closely related to the rippled and labyrinthine/sinusoidal patterns, as exemplified by our cases, in which these arrangements sometimes occurred simultaneously.

A hitherto unrecognized variant of solid-pseudopapillary neoplasm of the pancreas is reported. The tumor presented in the pancreatic head of a 57-year-old female patient. It was a well-circumscribed, encapsulated nodule measuring 27 mm in diameter, with variegated yellow to brown and gray cut surface. Histologically, the neoplasm was composed of uniform polyhedral cells arranged around delicate fibrovascular cores retaining their solid pattern in the periphery, whereas central parts of the tumor were characterized by the formation of papillae and smaller pseudocysts. Neither mitotic activity nor invasive growth were found. Immunohistochemically, tumor cells were positive for vimentin, neuron-specific enolase, and CD56, whereas they were negative in reactions with antibodies directed against other neuroendocrine markers, cytokeratins, melanocytic markers, and pancreatic amylase. In addition to these typical findings, intracellular pigmented granules were found in the darker brown zones of the tumor. They were positively stained in periodic acid-Schiff reaction after diastase digestion, sudan black B, and in Schmorl stain. In contrast, they were not stained with Fontana-Masson, Ziehl-Neelsen, and Perls stains. Ultrastructurally, the pigment consisted of dense granules with lipid droplets resembling modified lysosomes. These results exclude the possibility of a melanogenic nature of the pigment and instead determine it as lipofuscin.

We report a case of reactive syringofibroadenomatous hyperplasia in peristomal skin. The patient was a 62-year-old woman who had undergone abdominoperineal resection of the rectum for rectal adenocarcinoma with subsequent colostomy 2 years earlier. Clinically, a nodule and small, whitish, warty lesions developed at the outer margin of the stoma extending onto the adjacent skin. Following a clinical suspicion of adenocarcinoma, recurrent at the colostomy site, a 5 x 4 x 3-cm excision of the peristomal skin and the affected portion of the stoma was performed and submitted for histologic examination. The biopsy revealed a peculiar composite lesion of reactive syringofibroadenomatous hyperplasia and the excised part of the stoma. Several unusual histopathological features were detected in the syringofibroadenomatous part of the lesion such as the formation of plentiful hybrid epidermal-colonic mucosa glandular structures, intraepidermal areas of sebaceous differentiation, koilocytic changes, induction of rudimentary hair follicles, and intradermal mucinous lakes. The cellular composition of the glandular structures was mainly similar to that seen in a normal colonic mucosa epithelium. They also contained occasional Paneth cells. Being located at a distance from the stoma, these accentuated colonic mucosa epithelial glands reaching the epidermis may be a diagnostic pitfall prompting the consideration of adenocarcinoma involving the stoma. The rudimentary follicles and sebaceous differentiation were probably induced by an altered stroma and/or human papillomavirus (HPV): HPV, type 36 was identified by PCR using consensus primers followed by sequencing of the PCR products.

Brooke-Spiegler syndrome is an autosomal dominantly inherited disease with predisposition to cutaneous adnexal neoplasms, most commonly cylindromas and trichoepitheliomas. We report a patient in whom 11 lesions were removed from the scalp and face for various reasons over a period of 3 years. The histopathological survey revealed a plethora of benign adnexal neoplasms showing apocrine, follicular, and sebaceous differentiation occurring independently and conjointly. The histopathological spectrum in our patient included cylindromas, spiradenomas, trichoepitheliomas, small nodular trichoblastomas, and lymphadenomas. Many lesions had hybrid features of two or more neoplasms. By far the most common composite tumor was spiradenocylindroma. Some spiradenocylindromas demonstrated prominent sebaceous or trichoblastomatous differentiation or both. We suggest the terms "sebaceous spiradenocylindroma" and "trichospiradenocylindroma" for these lesions. The occurrence of sebaceous and trichoblastic differentiation in spiradenocylindromas is a further proof that spiradenoma and cylindroma are not eccrine tumors but neoplasms of the folliculosebaceousapocrine unit.

Three patients with Gardner's syndrome having benign fibrous proliferations in the soft tissues and the oral cavity are presented. Lesions in all three patients were morphologically different. Two excised lesions in Case 1 were histologically identical to nuchal-type fibroma (NTF) and one lesion in this patient was an epidermal cyst. Case 2 had a lesion located in the soft tissues of the shoulder, which was morphologically similar to NTF and, in addition, contained mildly atypical and multinucleated fibroblastic cells. The oral lesion in Case 3 looked like a fibroma and was morphologically different from all fibrous lesions that have ever been described in Gardner's syndrome. The cases in the present report show that the term Gardner's fibroma is just a descriptive name encompassing a spectrum of morphologically different benign fibrous proliferations associated with this syndrome. Therefore, the term Gardner's fibroma should not be used as a specific name for NTF arising in patients with Gardner's syndrome as suggested in the most recent WHO classification of soft tissue and bone tumors.

Adenomatoid tumor (AT) is a benign, relatively rare neoplasm occurring primarily in the genital tract of both genders. Histologically, ATs were composed of fibrous tissue, which are separated by numerous slit-like and pseudotubular spaces. Peculiar "thread-like bridging strands" (TBS) crossing the pseudotubular spaces are typical morphologic feature. In this study, the frequency of occurrence of these TBS within a large series of ATs in various organs was examined. Sixty-nine cases were included in our study. Twenty-eight cases occurred in women, 41 cases in men. Tumors were located in the myometrium, fallopian tube, ovary, epididymis, tunica albuginea, and testicular parenchyma. Tumor size ranged from 0.8 to 8.2 cm (mean, 2.7 cm). TBS were found in 100% of cases. Presence of thin intraluminal TBS within ATs was a constant morphologic feature independently on gender and localization of the lesions. Ultrastructurally, they were always formed by apposition of attenuated cytoplasm of two adjacent mesothelial cells. In our opinion, TBS are morphologically very specific for ATs and we are not aware of any other epithelial structure in any organ demonstrating as appearance similar to these TBS of ATs.

A case of dermatofibrosarcoma protuberans (DFSP) with epithelial membrane antigen (EMA)-positive cells is described. The tumor was excised from the left groin of a 28-year-old woman. It showed characteristic histologic features of DFSP with typical diffuse immunohistochemical positivity for CD34. Moreover, scattered neoplastic cells expressed EMA, suggesting perineural cell differentiation. Ultrastructural study found perineurial cell features, such as thin long bipolar cytoplasmic processes, pinocytotic vesicles, fragments of external lamina and/or external lamina-like material, attachment plaques, and desmosome-like junctions. This observation, together with previous immunohistochemical findings of EMA-positive cells in a subset of DFSPs, strongly suggests perineurial cell differentiation in these tumors. DFSP should be included in the differential diagnosis of EMA-positive spindle cell lesions of superficial soft tissue and skin.

Hyponatremia is a well-known phenomenon in cancer patients. The aim of our retrospective study was to assess the relationship of natremia levels to predict treatment with erlotinib and also to assess the prognosis of patients with hyponatremia.We analyzed data of 544 patients with advanced-stage non-small cell lung cancer (NSCLC) treated with erlotinib.Hyponatremia was measured in 21.5 % of patients before treatment with erlotinib. We found a significant increase in the effectiveness of treatment with erlotinib in patients with normal levels of sodium to hyponatremic patients. Progression-free survival (PFS) and overall survival (OS) were also significantly higher in patients with normal natremia. Multivariate Cox model analysis demonstrated that natremia was an independent factor for PFS and OS.We reported hyponatremia not only as a prognostic marker in NSCLC patients but also as predictive marker of erlotinib treatment efficacy, being an independent factor at the present large retrospective study. Its possible effect in clinical practice is bigger thanks the simple possibility of testing of hyponatremia and the low cost of this biomarker.

The objective of the present study was to retrospectively analyze a cohort of patients who underwent surgery for colorectal cancer pulmonary metastases during a 12-year period.The sample included 75 patients who were monitored in terms of overall survival (OS) and disease-free interval (DFI) in relation to patient's age, preoperative values of biomarkers, type of surgery, number and size of metastases, occurrence of complications and length of hospitalisation.A total of 95 surgical interventions were performed and 133 metastases were removed. Out of these, 28% of patients were free of any signs of relapse or disease progression for 5 years after metastasectomy. Those with two or more metastases are 2.3-times more at risk of disease progression. Tissue polypeptide specific antigen (TPS) values above the 140 IU/l cut-off point increase the risk of progression 3.9-times. The five-year survival rate among the group was 45%. Patients with 2 or more metastases are 2.7-times more at risk of death. TPS values above the 140 IU/l cut-off increase the risk of death 5.5 times, and carbohydrate antigen CA19-9 values above the 28 IU/ml cut-off point increase the risk of death by 3.2 times.The number of metastases and the preoperative TPS values are decisive prognostic factors influencing both OS and DFI.

Here we report 3 cases of renal oncocytoma with a dominating small cell component arising in adult women. These 3 cases of small cell variant of renal oncocytoma were found among 134 cases of oncocytomas of the kidney in the routine and consultation files of the authors. Two of 3 cases were initially thought to be a malignant tumor by the referring pathologists. In all 3 cases minor areas of the tumors, which were identical to the classical renal oncocytomas were found. The small cell areas were arranged in a characteristic organoid pattern different from all the known types of the renal benign and malignant tumors. We summarize all morphologic, immunohistochemical, and ultrastructural features of this unusual oncocytoma variant with regard to its differential diagnosis. Int J Surg Pathol 9(3):215-222, 2001

We describe a 45-year-old man who had a 2-year history of a slowly enlarging tumor in the left parotid gland. Histologically, the tumor was a mucinous cystadenoma with focal apocrine differentiation, which revealed a widespread invasive micropapillary adenocarcinoma component. A rim of lymphoid tissue surrounded the margins of the micropapillary carcinoma. The invasive micropapillary adenocarcinoma component was morphologically identical with the invasive micropapillary carcinoma of the mammary gland. The tumor is different from so-far recognized salivary gland tumor entities.

Aims We report a review of our institutional and consultation files in order to select cases of hitherto unrecognized type of adenocarcinoma occurring in the tongue. Materials and results Eight cases of a characteristic adenocarcinoma of the tongue resembled solid and follicular variants of the papillary carcinoma of the thyroid. All the tumours were unencapsulated and were divided by fibrous septa into lobules. Major parts of the lesions were composed of areas with solid and microcystic growth patterns. The most striking cytological feature was that the tumour nuclei were pale-staining with a ‘ground glass’ quality, and they often appeared to overlap. Immunohistochemically, the tumours expressed cytokeratin and S100 protein and, focally, actin; thyroglobulin was negative. Ultrastructurally the cells had clefted nuclei, and the cytoplasm contained a few mitochondria, lysosomes and Golgi apparatus. Many tumour cells had combined features of both myoepithelial and secretory differentiation—well formed microvilli on their apical borders and bundles of microfilaments. At first presentation, all eight patients had metastases in the regional neck lymph nodes, but all are alive 2–6 years after the initial excision and irradiation. Conclusion We describe a distinctive type of adenocarcinoma of the tongue, for which we propose the name cribriform adenocarcinoma of the tongue (CAT). CAT usually presents with metastases in the neck lymph nodes at the time of presentation. We hypothesize that the tumour might arise from the thyroglossal duct anlage.

Syringocystadenoma papilliferum is a benign tumor most commonly located on the scalp or face, and it often arises within a nevus sebaceus of Jadassohn. We describe a 61-year-old man with syringocystadenoma papilliferum developing within a nevus sebaceus with sebaceous differentiation in an intradermal tubular apocrine component of the syringocystadenoma papilliferum. Although some adnexal neoplasms that develop in association with a nevus sebaceus may exhibit conjoint sebaceous, follicular, or apocrine differentiation, reflecting close embryological relations of the folliculosebaceous-apocrine unit, the feature we report on has not previously been described to the best of our knowledge.

The authors report two examples of nodular hyperplasia of the Bartholin gland. Each occurred in the vulva, close to the introitus of women aged 33 and 49 years, who presented with slightly painful lesions that were clinically thought to be cysts. Grossly, both masses exhibited a multilobular architecture, were elastic, were gray in color, and measured 4 cm and 3.2 cm in greatest dimension. On microscopic examination, the lesions looked similar and exhibited an increased number of secretory acini, with maintenance of the normal duct-acinar relationship--features compatible with nodular hyperplasia. Rare dilated ducts were observed, and intraluminal inspissated secretions were occasionally seen. In one case, there were a focal mild inflammatory infiltrate, squamous metaplasia of larger ducts, and rare ruptured ducts with extravasated stromal mucin. Clonality analysis performed in one case revealed a monoclonal pattern, suggesting that the lesion may be a neoplastic process rather than simple reactive hyperplasia.

We describe three cases of benign signet-ring cell aggregates in the colon associated with pseudomembranous colitis, adenomatous polyp of the colon and ulcerated mucosa of the gallbladder excised for gallstones. In all cases, we found loose, benign signet-ring cell aggregates overlying the ulcerated mucosa surface, simulating signet ring-cell carcinoma. The most important sign of the benign signet-ring cell aggregates is that they are always confined to the surface of the mucosa of the intestine or gallbladder mucosa or crypts of the intestinal epithelium. In no case did we see an invasion of these cells into the lamina propria of the mucosa. In all cases, the benign signet-ring cell aggregates were immunohistochemically positive with antibodies to cytokeratins. The occurrence of benign signet-ring cell aggregates is a rare and very misleading diagnostic pitfall which must be differentiated from signet-ring cell carcinoma of the colon and gallbladder.

Ossifying fibromyxoid tumor of soft parts is an unusual benign neoplasm, with a tendency for local recurrence. Its typical microscopic appearance is that of a multinodular proliferation of round to spindle shaped cells separated by fibrous bands in which bone formation is often seen. Herein, we present the clinicopathologic features of 17 examples of this tumor with particular emphasis on some unusual histopathologic features that may place pitfalls in the diagnosis of this tumor, including satellite micronodules, mucinous microcysts, absence of myxoid areas, crush artifact, multiple microcalcifications, epidermoid cysts, atypical chondroid differentiation with binucleate lacunar cells, pericytic growth pattern, and malignant change. Awareness of these unusual morphologic features should lead to a search for areas displaying the more typical features of ossifying fibromyxoid tumor to arrive at a correct diagnosis.

Sir, mesenchymal tumors of the pancreas are exceedingly rare, accounting for less than 1% of all pancreatic tumors, and most of them have been reported in small series or as single case reports. This group of pancreatic tumors includes leiomyosarcoma, malignant peripheral nerve sheath tumor, malignant fibrous histiocytoma, liposarcoma, rhabdomyosarcoma,hemangiopericytoma,schwannomaandsolitary fibrous tumor. In the gut, mesenchymal tumors are more common, and the majority of these are formed by gastrointestinal stromal tumors (GISTs). GISTs are defined as KIT-positive mesenchymal spindle cell or epithelioid neoplasms showing differentiation toward the interstitial cell of Cajal. GISTs occur most commonly in the stomach (60–70%), small intestine (20–25%), colorectum (5%) and esophagus (