ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 CD14, CD7 and CD3. Immunohistochemistry confirmed CD20, CD10, CD19, TdT, CD34, PAX5 positivity and MPO, CD117, CD5, CD3 negativity. Findings were consistent with B-lympho- blastic leukaemia. (Comparison table with prior case reports in final submission) Conclusion: B-lymphoblasts with ARLI can be misleading and can lead to an erroneous diagnosis of myeloid leukaemia which might alter the management algorithm in a resource limited or an emergency on call setting where morphology is heavily relied upon. Although rare, the finding of ARLI does not preclude the diagno- sis of lymphoblastic leukaemia and underscores the importance of comprehensive immunophenotypic workup aiding in an accurate diagnosis and reflex molecular testing resulting in optimal patient management. E-PS-10-013 Multiple small bowel perforations: an aggressive haematologi- cal cause R. Rana*, H. Maddumage, J. Warnick, I. Bagwan *Royal Surrey County Hospital, United Kingdom Background & objectives: Small bowel perforation as clinical presentation is seen in inflammatory bowel disease, tuberculosis, ischemia, obstruction and malignancy. Here we discuss a case of extranodal NK/T cell lymphoma presenting as multiple small bowel perforations. Methods: Clinicopathological analysis of a case presenting with multiple small bowel perforations. Results: A 68-year-old male who presented to emergency depart- ment with abdominal pain. CT scan revealed multiple small bowel perforations. A segmental jejunectomy and ileectomy was per- formed. Histology confirmed perforations with presence of atypi- cal large lymphoid cells involving the entire bowel wall. These atypical cells were positive for CD3, CD56, CD2 (weak), Bcl2 (weak), Granzyme B and EBV (EBER-ISH). Molecular analysis was negative for specific mutations. A diagnosis of extra nodal high-grade NK/T cell lymphoma was offered. Subsequent PET scan done revealed a nasal mass. Unfortunately, the patient died in a few days following the surgery and biopsy of the nasal mass could not be performed. Conclusion: Small bowel perforations can occur in variable com- mon clinical conditions. This case highlights the importance of thorough morphological and immunohistochemical analysis required in recognising unusual causes such as NK/T cell lym- phoma of small bowel causing perforations. Awareness of such entities amongst general physicians and surgeons would be ben- eficial in clinical practice as these patients present with advanced disease and have poor outcome. E-PS-10-014 Acute myeloid leukaemia presenting with an acute fibrinous and organizing pneumonia J. Filipe*, E. Dutra *Serviço de Anatomia Patológica, Instituto Português de Oncologia de Lisboa Francisco Gentil, Lisbon, Portugal Background & objectives: Acute fibrinous and organizing pneumo- nia (AFOP) is an unusual histologic pattern of lung injury. In acute myeloid leukaemia, pulmonary injury is mostly due to infection or other malignancies. We report a case of acute monoblastic leukaemia (AML) presenting as AFOP. Methods: Patient history was collected from the clinical files and histologic samples were reviewed. PubMed search for similar cases in the English literature was performed. Results: A 56-year-old-man presented with marked asthenia. Blood tests showed anaemia, leukopenia, and elevated PCR. An angio-CT-scan revealed peripheral consolidations on the left lung. The patient was hospitalized in the context of a commu- nity-acquired pneumonia and bicytopenia of unknown aetiology. Bone marrow workup revealed an AML. During hospitalization, despite multiple antibiotic cycles, he had persistent fever which delayed the beginning of chemotherapy. Blood and bronchoalveo- lar lavage cultures were negative. A follow-up CT-scan showed bilateral pulmonary infiltrates. A lung biopsy was performed and a diagnosis of AFOP was rendered, after which corticotherapy was instituted with imagiological improvement. Treatment for the AML was also initiated and the patient currently awaits bone marrow transplant. Conclusion: Pulmonary manifestations of acute myeloid leukaemia are usually misinterpreted as infectious disease, undergoing multi- ple antibiotics without clinical improvement. This report increases awareness of this unusual manifestation, enabling correct diagnosis and treatment whilst avoiding unnecessary delays in chemotherapy. E-PS-10-015 Composite mantle cell and diffuse large B-cell lymphoma J. Filipe*, M. Rito, A.F. Ferreira, P. Gameiro, J. Cabeçadas *Serviço de Anatomia Patológica, Instituto Português de Oncologia de Lisboa Francisco Gentil, Lisbon, Portugal Background & objectives: Composite lymphoma is the presence of two or more different subtypes of lymphoma in the same organ. We describe a rare case of a composite mantle cell lymphoma (MCL) and diffuse large B-cell lymphoma (DLBCL), along with literature review. Methods: The clinical history was obtained from the clinical file. FISH complemented histological diagnosis for CCND1. IGH and IGK gene rearrangement analysis was based on PCR and Genescan- ning using the BIOMED-2 protocols. A PubMed search for similar cases was performed. Results: A 77-year-old-man presented with a cervical mass. CT- scan revealed a large lymph node (LN), and also submandibular, mediastinal and lombo-aortic. An excised cervical LN showed two distinct B-cell populations: large-cells with necrosis, BCL6+, MUM1+, BCL2+, and MYC+; and small-cells, CD5+, CCND1+, SOX11+. Both were CD3-, CD10-, CD23-, EBER-. A CCND1 break by FISH was present only in the small-cell population. After macrodissection, IGH and IGK PCR-based analysis was in agree- ment with the presence of two clonal populations. A diagnosis of a composite MCL and DLBCL was made. PET-CT scan revealed FDG-avid lymphadenopathies above and below the diaphragm. Only MCL was found on the bone marrow. The patient is under R-CHOP. Conclusion: Composite lymphomas are interesting models for lymphomagenesis understanding, and to our knowledge, this is the fifth described case of a composite MCL/DLBCL. All cases in the literature are male patients, one corresponding to a primary testicular lymphoma. Excisional biopsy is imperative for diagnosis since a FNAC may miss one of the components. The presence of two morphological, immunohistochemical and genetically different cell populations, suggests two independent lymphomas as opposed to the unlikely transformation of MCL. S275