ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 Results: Patient subsequently lost in follow up and came back 4 years later with another positive faecal occult blood test. The same terminal ileal ulcer with similar histological findings on biopsy were obtained. A clinical impression of Crohn’s disease was rendered after excluding infectious aetiologies. Computerised tomography (CT) scan showed enhanced, circumferential mural thickening in the terminal ileum with surrounding fat stranding, suspicious for neoplastic conditions. Right hemicolectomy was eventually performed 3 months later and disclosed a FL, WHO grade 2 and 3A, involving the terminal ileum, appendix, caecum and mesenteric lymph nodes, with an overlying ulcer and granulation tissue. No evidence of Crohn’s disease is identified. Conclusion: The review of slides from previous biopsy proved no discrete evidence of lymphoma. The case re-emphasizes the importance of representative sampling for histological examination and interdisciplinary discussion. E-PS-10-004 Aggressive CD5 + MALT lymphoma in a patient from an ultra- sound-guided minimally invasive autopsy: a case report M. García-Martínez*, C. Fuente-Díaz, A. Encinas-Muñiz, M.d.l.P. González-Gutiérrez, V. Blanco-Lorenzo, E. Colado, C. González del Rey-Rodríguez, J.R. Riera, M. Berríos-Hernández *Department of Pathology, Central University Hospital of Asturias, SESPA, Oviedo, Spain Background & objectives: Expression of CD5 has been described typically in CLL/SLL and mantle cell lymphoma, but also in a subset of MALT lymphomas. According to the literature, CD5+ MALT tends to originate in nongastric locations with an aggressive behaviour and disseminated disease. Methods: We report a case of an 85-year-old woman previously diag- nosed with ocular aggressive MALT lymphoma, with both parotids involvement and multiples lymphadenopathies. An Ultrasound Guided Minimally Invasive Autopsy (US-MIA) was accomplished. US Fine Needle Aspiration and Core Needle Biopsy of right orbital and parotid lesions were performed, and adequate material were sent to Flow Cytometry, Cytogenetic and Molecular Oncology laboratories. Results: The gross autopsy examination showed tumoral lesions in both breasts, trachea, larynx, thyroid gland, oesophagus, right orbital and both parotids that were confirmed later in the microscopic study. All these lesions were morphologically identical, formed by small- to medium-sized cells with round to slightly irregular nuclear contours, dispersed chromatin, and a moderate amount of cytoplasm. The lymphoma cells expressed CD5, CD20, PAX5, BCL2 and were negative for CD10, CD23, Cyclin D1, SOX11, BCL6, MUM1, MNDA and LEF1. Moreover, molecular oncology reported a mutation in MYD88 gen, however our patient never debuted with high levels of IgM. Conclusion: This case report is interesting for so many reasons: we describe a CD5+ MALT lymphoma with a disseminated disease at diagnosis, with mutation in MYD88 and an extraordinary aggres- sive behaviour with a nule response to chemotherapy, causing a prompt fatal outcome to the patient. Besides that, the autopsy study was performed with an unconventional method: ultrasound-guided minimally invasive autopsy with subsequent Rapid On-Site Evalu- ation -ROSE- of tissue to ensure an adequate specimen on site for additional studies and postmortem diagnosis. E-PS-10-005 Large B-cell lymphoma with IRF4 rearrangement involving lacrimal gland: a case report S. Na*, K.R. Lee, G. Choe, Y.K. Jeon, J.H. Paik *Department of Pathology, Seoul National University Bundang Hospital, Republic of Korea Background & objectives: Large B-cell lymphoma with IRF4 rear- rangement (LBCL-IRF4) is reported in the paediatric population, pre- dominantly in tonsil and neck lymph nodes. We report a case of LBCL- IRF4 in an adult female at an unusual location, the lacrimal gland. Methods: A 34-year-old female presented with persistent epiphora on the left eye for two years despite antibiotics and conservative management. Computed tomography and dacryocystography showed a cystic soft tissue lesion in the proximal and distal lacri- mal duct opening with duct obstruction with sac dilatation. Exci- sional biopsy was performed. Grossly, the tissue was whitish, soft and friable. Results: Microscopic examination revealed diffuse proliferation of large atypical cells with coarse chromatin, irregular membranes, and occasional small basophilic nucleoli with frequent tingible- body macrophages and mitosis. Immunohistochemistry and EBV in situ hybridization revealed that the tumour cells were positive for CD20, Bcl-6, CD10 and Mum1 but negative for Bcl-2, cyc- lin D1, c-Myc and EBV-encoded RNA, with no visualization of follicular dendritic cells by CD21 or CD23. Fluorescence in situ hybridization revealed IRF4 rearrangement by using an IRF4/ DUSP22 break-apart probe but not the c-Myc or Bcl-2 gene. No other involvement was observed in bone marrow biopsy, peripheral blood smear or positron emission tomography. The final diagnosis of LBCL-IRF4 was made. Conclusion: LBCL-IRF4 is a rare entity recognized in the revised 4th edition of the WHO Classification of Tumour. It manifests as diffuse, follicular or mixed architecture, making morphological dif- ferential diagnosis challenging. As epidemiologic and pathogenetic information are limited, coexpression of CD10, BCL6 and MUM1 should raise suspicion of LBCL-IFR4. Even with unusual extran- odal sites and age, IRF4/DUSP22 FISH may lead to the accurate diagnosis of LBCL-IRF4. Funding: This study was supported by the Basic Science Research Program through the National Research Founda- tion (NRF) funded by the Ministry of Science and ICT (MSIT) (NRF-2019R1F1A1061920) E-PS-10-006 HHV8-positive diffuse large B-cell lymphoma (DLBCL), NOS - a case report and review of the literature O. Tzaida*, E. Souka, G. Galanopoulos, M. Terzi, L. Karelis, M. Dadakaridou *Metaxa Cancer Hospital, Greece Background & objectives: HHV8-positive DLBCL NOS, usually arising in association with Multicentric Castleman Disease (MCD) and originating from a naive IGM lambda-positive B cell, is a rare neo- plasm with characteristic plasmablastic morphology. A case of HHV8- positive DLBCL, NOS associated with MCD is presented. Methods: A 74-year-old male patient with history of MCD was admitted with worsening constitutional symptoms (fever, fatigue, loss weight), enlarging of cervical lymph nodes and massive sple- nomegaly. Laboratory findings included severe anaemia, neutro- penia, thrombocytopenia, hypergammaglobulinaemia and elevated C-reactive protein. A right cervical lymph node, measuring 1cm at maximum diameter, was excised. Results: Histopathological examination revealed effacement of lymph node by a lymphoid neoplasm consisting of large, plas- mablastic cells coalescing to large aggregates. Tumour cells had S272