Splenic Diffuse Red Pulp Small B Cell Lymphoma: Transformation To Diffuse Large Cells B Lymphoma
Authors: Bezerra Evandro Dantas , Fontenele Leila Patricia , Pereira Juliana , de Padua Covas Lage Luis Alberto , Maciel Felipe , Barquinero Leticia , Carvalho Priscila R , Siqueira Scheila , Velloso Elvira RP 
Published: October 2019

Abstract

Objective
Report immunophenotypic and genetic aspects and clinical course of a case of Splenic Diffuse Red Pulp Small B Cell Lymphoma with transformation to diffuse large cell.

Introduction
Until recently, only Hairy Cell Leukemia was recognized as B chronic lymphoproliferation with primary involvement of the splenic red pulp. The 2008 WHO classification included two new provisional entities: Splenic diffuse red pulp small-B cell lymphoma and Hairy Cell Leukemia variant. These entities are rare, encompassing less than 1% of B chronic lymphoproliferation, characteristically presenting as an indolent clinical course and good control with splenectomy.

Case report
Female, 29 years old, with non-replicative chronic hepatitis B, and splenomegaly detected 7 years before without evidence of portal hypertension or schistosomiasis. Two months before admission to our hospital, she developed increasing splenomegaly for 39cm, B symptoms and abdominal lymphadenopathy. CBC showed Hb: 8,1g/dl, platelet: 80.000/mm3, WBC: 12.000/mm3 with 85% of abnormal lymphoid cells with immunophenotyping CD45++/CD19+/CD20++/CD25+/CD23dim/CD200dim/FMC7+/CD11c-/CD103- and cykappa restriction. Complex karyotype in PB suggested lymphoproliferative disorder, with strutural abnormalities in 14q32, isocromosomes 8 and 17, deletions 6q and 7q and trisomy 18. FISH studies showed extra copy of MYC and p53 deletion. Bone marrow aspirate showed 7,6% of cells with same phenotype. CT and PET-CT showed splenomegaly of 39cm (SUV: 6.1), hepatomegaly (SUV: 3.2), abdominal lymph node conglomerate (SUV: 6.3), cervical and mediastinal lymphadenopathy with no increase in dimensions (SUV: 3,8). The patient was submitted to splenectomy and histological findings revelead mature lymphoid neoplasm, ranging from small to intermediate cells with few large cells, primary from spleen red pulp and diffusely infiltrating the sinusoidal spaces and secondly the white pulp (CD20+, DBA44+, CD5-, CD10-, CD23-, CD3-, cyclin D1- and Ki67: 40%). The cytogenetic analysis of the spleen showed similar complex karyotype as seen in PB. With the diagnosis of Splenic Diffuse Red Pulp Small B Cell Lymphoma with aggressive transformation to diffuse large cell, she was submitted to 8 cycles of R-CHOEP and is in complete remission, waiting for consolidation with high-dose chemotheraphy followed with peripheral stem cells rescue.

Discussion
Splenic Diffuse Red Pulp Small B-cell Lymphoma was included as a provisional entity in WHO 2008 classification. The few cases reported show an indolent course with good response to splenectomy. In this case the diagnosis was suspect with clinical course, cytogenetic and flow cytometry PB studies and confirmed after splenectomy when the clinical course of disease changed with B symptoms, spread to peripheral blood with atypical cells and increased proliferative markers, such as LDH. This fact highlights the difficulty in establishing the diagnosis of this entity during the course of prolonged and indolent disease, manifested by splenomegaly oligosymptomatic often neglected by physicians and by the patients themselves.

Disclosures:
No relevant conflicts of interest to declare.