ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 E-PS-10-016 Testicular plasmacytoma. A case report and correlation with imaging findings E. Baliou*, E. Psychogiou, P. Megas, D. Riga, K. Papadopoulou, A. konstantinidou, I. Vamvakaris *General Hospital of Thoracic Diseases of Athens "Sotiria", Greece Background & objectives: Plasmacytoma refers as a malignant plasma cell tumour growing within bones or extraosseous (extramed- ullary). Testicular plasmacytomas are rare malignant neoplasms with relatively poor prognosis. At the time of diagnosis, our patient did not have multiple myeloma Methods: A 87 year-old -patient presented to our hospital with a painless testicular mass, accompanied by a sense of heaviness. CT scan reveals a solid mass 6,5X5X4 cm in dimensions. An orchi- ectomy was the surgery of choice. On dissection of the surgical specimen, a brownish mass was recognized. Results: Microscopic examination showed a lesion composed entirely of mature and immature plasma cells, ranging from small and mature to large in size and atypical cells with prominent nucle- oli. Sheets of plasma cells with abundant pink cytoplasm were also present invading the seminiferous tubules. Sparse, single, pale staining nuclear inclusions, with the morphologic features of "Dutcher bodies" were also present. Immunohistochemically, the neoplasm had the following profile: CD138 (+), CD19 (-), CD20 (-), CD117 (-), PLAP(-), CD56 (-), KLMW rarely (+). Confirma- tion of a clonal plasma cell lesion was accomplished immunohis- tochemically for Ig light chains. Conclusion: Plasmacytomas have been described in bones and in other tissues, most commonly in the upper respiratory tract with spread to cervical lymph nodes, but they may occur also in the gas- trointestinal tract, breast, testis and in many other anatomical loca- tions. Very few have been reported in the testis. Isolated testicular plasmacytoma accounts for only 0,03-0,1 %. The vast majority of patients with testicular plasmacytoma either have disseminated disease at the time of diagnosis, or develop disseminated disease later in life E-PS-10-017 ALK-positive large B-cell lymphoma: a very rare and aggres- sive neoplasm C.M. Vieru*, F.J. Menarguez, J. Huerta Aragonés, C. Garrido Colino, F.J. Díaz Crespo *Hospital General Universitario Gregorio Marañón, Spain Background & objectives: ALK-positive B-cell lymphoma is a rare CD-20 negative aggressive non-Hodgkin lymphoma with less than 200 cases published in the literature. We describe a new refractory case with a view to improving its knowledge and so, its diagnostic and therapeutic management. Methods: We report the only case diagnosed in our hospital and describe clinical, radiological, histopathological, immunopheno- typic and molecular features. This is a 12 year-old boy with a left axillary lump and intermittent scapular pain without any other medical history. Imaging tests was performed and a lytic scapular lesion with axillary and splenic adenopathic conglomerates were evidenced. Results: Axillary fine-needle aspiration and core-needle biopsy were realized and revealed a completely infiltrated lymph node tissue by a diffuse neoplasm, composed of monomorphic large cells with plasmablastic features with round pale nuclei containing a large central nucleolus and abundant amphophylic cytoplasm. Immunohistochemical stains were positive for CD45, CD79, CD138, MUM-1, IgA-Kappa, c-MYC, EMA, BCMA and ALK with restricted granular cytoplasmic staining pattern and pre- sented a very high proliferation index. Lymphoid markers, EBER and HHV8 resulted negative. FISH studies confirmed ALK trans- location t(2;17) and clonality tests showed immunoglobulin heavy chain rearrangement. Two years after diagnosis, in stage III dis- ease, is receiving the sixth-line of treatment awaiting for CAR-T cell therapy (BCMA). Conclusion: Large B-cell lymphoma is one of the most com- mon lymphoma. Recent advances in molecular biology allowed to describe new subtypes, including ALK-positive large B-cell lymphoma, a rare entity that represent a diagnostic challenge. It is important to correctly diagnose it as long as its aggressivity turns it into a therapeutic problem with a poor median prognosis (<2 years). Our patient’s refractory process shows that despite the variety of therapies described, additional research is necessary to better understand this pathology. E-PS-10-018 Beyond reactive lymphadenitis: what else can they tell us? D. Bueno Sacristán*, P. García Abellás, I. Carretero Barrio, A. González Rodríguez, A. Santón Roldán, M.E. Reguero Callejas, M. García-Cosio Piqueras *Hospital Universitario Ramón y Cajal, Pathology Department, Spain Background & objectives: Lymph node follicular hyperplasia and plasmacytosis have been considered as non-specific alterations with little attention in the literature. However, these findings may lead the pathologist to include an autoimmune process in the diagnosis of a lymph node biopsy. Methods: We present the morphological and immunohistochemical features in a series of four cases of autoimmune-related lymphadenopathies, three systemic lymphadenopathies (with no autoimmune disease related) and two multicentric Castleman disease cases diagnosed between 2018 and 2022; emphasizing the location and quantification of plasma cells within the lymph node. Epidemiological data and clinical findings are also included in the study. Results: All four patients diagnosed with an autoimmune process showed florid follicular hyperplasia and varying degrees of poly- typic inter (grade 2-3) and intrafollicular (grade 1) plasmacytosis. No light chain restriction was detected in such cases. Within the systemic non-autoimmune –related lymphadenopathies, two cases proved intrafollicular (grade 1-2) plasmacytosis with kappa light chain restriction and mild interfollicular plasmacytosis (grade 1). Multicentric Castleman disease showed intense interfollicular plasmacytosis (grade 3) with no intrafollicular presence of plasma cells. Conclusion: Follicular hyperplasia and polytypic inter and intrafollicular plasmacytosis are common findings within autoimmune affected patients. The pathologist must be capable to recognize these features and include the possibility of an underlying autoimmune process in the differential diagnosis in patients with multiple lymphadenopathy. E-PS-10-019 Kikuchi-Fujimoto disease following COVID-19 infection: case report A.M. Ciongariu*, A. Dumitru, I. Dandu, M. Sajin, M. Costache *University Emergency Hospital, Romania S276