ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 G. Moreno De Juan*, A. Pérez Del Barrio, G.G. Yange Zam- brano, E.G. Herrera Romero, S. Montes Moreno *Hospital Universitario Marqués de Valdecilla, Spain Background & objectives: Kikuchi-Fujimoto disease (KFD) is a rare benign self-limiting disease which predominantly affects young women and Asian populations. KFD is characterized by cervical lym- phadenopathy and mild fever. We report a case of KFD following the SARS-CoV2 vaccination. Methods: A 30-year-old woman with no medical history of interest, presented left axillary lymphadenopathy with reactive appearance on ultrasound, 12 days after the first dose of SARS- CoV2 vaccination in the left arm. More than 6 weeks after the second dose, these adenopathies were increased in number and size on ultrasonography, so a core needle biopsy was requested. Results: Histological study revealed a lymph node parenchyma with paracortical hyperplasia and multiple circumscribed foci of necrosis with abundant karyorrhexis and eosinophilic debris. Numerous histiocytes (some C-shaped) and plasmacytoid dendritic cells were seen in association with apoptotic cells. No neutrophils or hematoxylin bodies were observed. The predominant cellularity corresponded to CD3+ T lymphoid population and nests of CD123+ plasmacytoid dendritic cells, especially around necrotic foci. The immunohistochemical study with CD30, kappa and lambda showed no alterations. Isolated fibrin thrombi in blood vessels were present. Histologic findings were compatible with a Kikuchi-type necrotizing lymphadenitis. Conclusion: Only three cases of KFD have been reported follow- ing vaccination against COVID-19. Although KFD pathogenesis is unknown, it is believed to be a consequence of an aberrant immune response of T cells and histiocytes to an immunogenic antigen (infectious agents or physicochemical factors). Because the patient had no discomfort before the vaccines were admin- istered, COVID-19 vaccine was the more likely cause of KFD. Vaccination should be added to the list of potential triggers/fac- tors associated with the development of KFD. E-PS-10-023 Clinical implication of CD30 expression in De Novo Epstein Barr virus-positive diffuse large B-Cell Lymphoma NOS N. Moulai*, R. Bennoui, M. Guermi, W. Ouahioune *Department of pathology and Cancer Research Laboratory, Blida University Hospital, Saad Dahleb University, Algeria Background & objectives: EBV+ Diffuse DLBCL NOS, is an aggres- sive clinicopathological entity recognized in the last edition of the 2016 classification of the World Health Organization (WHO). Our aim is to determine the impact of prognostic of CD30 expression in EBV(+)-DLBCL. Methods: CD30 expression was compared on 78 EBV(-)- DLBCLs including 67 with ABC and 11 GCB phenotype to 13 EBV(+)-DLBCLs ABC phenotype. The patients were treated by R-CHOP over a period of 44 months, from January 2015 to August 2019. The cut-off for CD30 positivity was 20% of neo- plastic cells. Results: In our series, there was a significant difference between the expression of CD30 EBV (+)-DLBCL and EBV(-)-DLBCL (p<0.001). CD30 was positive in 76.9% EBV(+)-DLBCL and 20.5% of EBV(-)-DLBCL. It was expressed in 70% of the non- GC ABC molecular subtype DLBCL. The Pearson test showed a significant correlation between EBER expression and CD30 expression (r=0.367, p=<0.000). CD30 was significantly asso- ciated with EBV status and survival in both CD30 and EBV positive. Patients showed a very low survival rate Log Rank (Mantel-Cox)=0.0008. The multivariate analysis by Cox regres- sion in our study retained CD30 as an independent variant (p=0.03). Conclusion: Expression of CD30 in EBV(+)-DLBCL is linked to a lower survival rate and poor treatment response suggesting a strong rationale for therapy targeted at the CD30 activation pathway for these patients positive for both CD30 and EBV. E-PS-10-024 Plasmacytoma of the testis as initial presentation of multiple myeloma: case report A. Tanevska Zrmanovska*, B. Krsteska, G. Petrushevska *Institute for pathology, North Macedonia Background & objectives: Extramedullary plasmacytoma represents 5% of plasma cell neoplasms. Plasmacytoma of the testis is extremely rare and may occur as isolated tumour or in concomitance with multiple myeloma. We report a case of testicular plasmacytoma in 77-year-old male patient. Methods: The physical examination and ultrasonography revealed enlarged left testicle. Based on a clinical diagnosis, an inguinal orchidectomy was performed. On gross examination the testicle measured 7x4x4cm and was entirely occupied by a solid white fleshy tumour. Formalin fixed, paraffin embedded tissue samples were stained with HE and immunohistochemically with CD138, MUM 1, CD79, CD3, CD20, CD117, PLAP and Ki 67. Results: Microscopic examination revealed a malignant neoplasm composed of atypical plasma cells with pale eosinophilic cytoplasm and polymorphic and polychromatic nuclei which diffusely obliterated underlying testicular parenchyma and infiltrating the epididymis and surrounding peritesticular fibrous tissue. Immunohistochemically the cells were positive for CD138, MUM1 and CD79 and negative for CD3, CD20, CD117 and PLAP with Ki67 80%. After period of two and half months the diagnose of multiple myeloma was established with bone marrow aspiration showed 60% plasma cells, flow cytometry with CD38 and CD138 plasma cells and serum protein immunoelectrophoresis IgA idiotype. Patient died after two-week therapy with corticosteroids, four months after initiate diagnose of plasmacytoma of testis. Conclusion: Testicular plasmacytoma is extremely rare presen- tation of extramedullary plasmacytoma. Taking into account the additional data obtained about the patient we concluded that in our case it was the first manifestation of systemic disease referred as multiple myeloma. E-PS-10-025 Atypical case of angioimmunoblastic T-cell lymphoma (AITL), cutaneous monoclonal plasma cell neoplasm and POEMS-like syndrome: a tricky confounding case R. de Paula*, V. Farnese, C. Ferreira, C. Oliveira, F. Costa, A.C. Lemos, G. Roberti, J. Pereira *A.C. Camargo Cancer Center, Brazil Background & objectives: Patients with AITL typically present with the onset of a systemic illness, but they rarely manifest typical findings of POEMS syndrome and skin nodules related to secondary plasma cell neoplasm. This case illustrates atypical manifestations and, therefore, its diagnostic challenge. Methods: A 73-year-old man was admitted to the hospital because of weakness, paresthesias and violaceous cutaneous plaques. Complementary tests revealed organomegaly, hypogonadism, enlarged lymph nodes and polyclonal gammopathy, although the S278