ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 amphophilic cytoplasm, vesicular nuclei and prominent nucleoli. The mitotic activity was high. Few follicles with atrophic hya- linized germinal centres, “onion skin”mantle zones and promi- nent endothelial venules, a morphology typical of CD, remained. The differential diagnosis included HHV8-positive DLBCL, NOS and HHV8-positive germinotropic lymphoproliferative disorder(GLPD). On immunohistochemical examination the plas- mablastic cells had a LCA+, CD20+, CD138+, MUM1+,HHV-8+ phenotype with lambda light chain restriction and cIGM strong expression. ISH for EBV-encoded small RNA (EBER) was nega- tive. The morphological and immunohistochemical results estab- lished the diagnosis of HHV8-positive DLBCL, NOS. Conclusion: HHV8-associated lymphoproliferative disorders include MCD, HHV8-positive DLBCL, NOS (EBV-negative usu- ally), and HHV8+ germinotropic lymphoproliferative disorder (GLPD) (EBV-positive usually). GLPD patients are asympto- matic and have a favourable response to chemotherapy or radia- tion, whereas HHV8+ DLBCL is associated with poor progno- sis. HHV8+ DLBCL patients in association with MCD usually experience a severe immunodeficiency. The disease, under these circumstances, has an aggressive course. Our patient, a week after the diagnosis, succumbed to his disease. E-PS-10-007 Hidden mantle cell lymphoma T. Lakic*, M. Šunjević, A. Ilic, A. Lovrenski, B. Krajnovic, M. Panjković *Faculty of Medicine University of Novi Sad, Serbia Background&objectives: Adenocarcinoma is the most common prostatic malignancy where clinical management, Gleason score (GS) and cancer staging (WHO/ISUP) play critical role in. Mantle cell lymphoma originates from malignant transformed B-lymphocytes of lymph follicle outer edge, with pathognomonic overexpression of CD5/Cyclin D1. Methods: Tissue specimens were H&E stained and analysed, as well as immunohistochemical biomarker panel for lymph nodes. Performing serial cuts, gross examination showed homog- enous appearance of many nodes that were white to greyish, with soft consistency and in different diameters. The prostate was enlarged, measured 6x5x2.5 cm and mostly homogenous in appearance, some spongy consistency and no visible defects dur- ing grossing. Results: A 68-year-old male was referred to our tertiary care institution for elective radical prostatectomy due to previously diagnosed adenocarcinoma performing prostatic core needle biopsy. Having performed a thorough histological examination, diagnosis of prostatic adenocarcinoma with Gleason score 3+4=7, ISUP GG2, was set. Microscopic analysis of lymph nodes were with no metastatic deposits, but unexpected, lymph node architecture was disturbed due to diffuse small lymphoid cell proliferation, with irregular nuclei, wide mantle zone and hyalinized blood vessels. After using immunohistochemical staining, it was shown expression for CD20/CD5/CyclinD1/Bcl-2 and negativity for CD3/CD10/Bcl-6 with proliferative index up to 20%, so additional diagnosis was set, and it was non-Hodgkin mantle B-cell lymphoma. Conclusion: A prostatic adenocarcinoma can extremely rarely be in a coexistence with undiagnosed lymphoproliferative disease, such as non Hodgkin mantle cell lymphoma in our case. This lymphoma is usually synchronously present with plasma cell dyscrasia or granulomatous diseases such as sarcoidosis. It can also occur with metastasis from a different anatomical site, but in the same lymph node. This case indi- cates that extensive and detailed lymph node examination is necessary in order to prevent underdiagnosed lymphoproliferations. E-PS-10-008 A rare case of an Epstein-Bar virus positive mucocutaneous ulcer in the rectum of an HIV positive patient. A case presenta- tion and review of literature A. Irfan*, V. Mateescu, K. Lankachandra *University of Missouri Kansas City, USA Background & objectives: Epstein-Bar Virus positive mucocutane- ous ulcers (EBVMCU) affect mucosal and cutaneous surfaces, rarely involving the rectum. We present a case of a rectal ulcer in a 40-year- old HIV positive male who complained of severe rectal pain radiating to his thighs. Methods: Examination under anaesthesia identified a rectal ulcer that was biopsied. The tissue biopsy was stained with Hematoxylin and Eosin. Following initial evaluation, additional stains including Pan-Keratin, SOX-10, MART-1, CD3, CD4, CD8, CD10, CD15, CD20, CD30, CD79a, Ki-67, MUM-1, PAX-5, EBV (EBER), OCT-2, BOB-1, HSV I, HSV II, CMV and GMS were performed. Literature review was done using PubMed. Results: The histomorphology of the lesion demonstrated a mucosal ulcer and nodular aggregates of inflammatory cells com- posed of small lymphocytes, eosinophils, granulocytes, plasma cells and histiocytes with scattered large atypical lymphoid cells morphologically mimicking Hodgkin/Reed-Sternberg-like cells. These cells were positive for EBV (EBER), CD30, MUM-1 and BCL-6. PAX 5, BOB1 and OCT-2 showed weak positivity. The cells were negative for CD15, CD20 and CD79a. Based on the histomorphology and immunohistochemical staining pattern, a dif- ferential diagnosis of EBVMCU versus mixed-cellularity classic Hodgkin lymphoma was entertained. The clinical history of HIV- positivity, the absence of lymphadenopathy and a reduced CD4/ CD8 ratio led to the final diagnosis of EBVMCU. Conclusion: EBVMCU, a relatively new entity, is associated with advanced age, iatrogenic immunosuppression, HIV/AIDs and post- transplant therapy. While EBVMCUs mimic malignancy, their indolent course typically results in spontaneous regression. The median age is >70-years. Per PubMed search, EBVMCUs primar- ily involve the oropharynx (69.3%) and cutaneous surfaces. Out of 186 cases reviewed only 3 showed rectal involvement (1.6%). It is important to keep EBVMCU in mind in isolated classic Hodgkin lymphoma-like disease, even in younger patients, especially if they are immunocompromised. E-PS-10-009 ALK-positive anaplastic large cell lymphomas (ALCL): our experience. Inter-observer variation in the interpretation of ALK immunohistochemistry staining M. Ortiz*, M. Veras, E. Revilla, E. Conde, C. Bárcena, I. Gal- lego-Gutierrez, J. Jiménez *Hospital universitario Doce de Octubre, Spain Background & objectives: ALK-positive anaplastic large cell lym- phoma (ALCL) is a rare T-cell lymphoma. We aim to characterize its clinical and histological features, and to analyse inter-observer varia- tion in evaluation of ALK expression patterns, which correlates with different fusion partner genes. Methods: This is a retrospective, descriptive report of ten cases diagnosed in the last ten years in the Hospital Doce de Octubre. Patients’ characteristics, such as age and gender, and clinical and histopathological data were subtracted from patients’ medi- cal records and analysed. Furthermore, ALK immunohistochem- istry staining patterns were re-evaluated by three pathologists and inter-observer variation was established using the kappa coefficient. S273