Villous lymphocytes in splenic large B-cell lymphoma with diffuse red pulp infiltration

First reported case of splenic diffuse red pulp small B-cell lymphoma with novel mutations in CXCR4 and TRAF3 genes

Splenic diffuse red pulp small B-cell lymphoma (SDRPL) is a rare B-cell tumor whose genetic characteristics are poorly understood. Here, we introduce the case of a 62-year-old patient with SDRPL who showed progressive elevation of lymphocytes and progressive spleen enlargement. Immunohistochemistry showed that CD20 and CD79a were positive, and the Ki-67 labelling index was approximately 5%, consistent with the pathological features of splenic B-cell lymphoma. Spleen tissue and peripheral blood samples from the patient were sequenced using a next-generation sequencing platform, and mutations possibly were detected in the CXCR4 and TRAF3 genes that may be related to the pathogenesis of the disease. This finding may provide insights into the molecular pathogenesis of SDRPL and assist in molecular diagnosis and targeted therapy for SDRPL.

A Review on Splenic Diffuse Red Pulp Small B-Cell Lymphoma

Splenic diffuse red pulp small B-cell lymphoma (SDRPL) is a rare disease, representing <1% of all non-Hodgkin lymphomas (NHL). The most common clinical manifestations include splenomegaly, lymphocytosis, and hemocytopenia. A diagnosis of SDRPL can be challenging, as it shares multiple clinical and laboratory features with splenic marginal zone lymphoma (SMZL), hairy cell leukemia (HCL), and HCL variant (HCL-v). Obtaining splenic tissue remains the gold standard for diagnosis. In the cases where splenic tissue is not available, diagnosis can be established by a review of peripheral blood and bone marrow studies. SDRPL is characterized by a diffuse involvement of the splenic red pulp by monomorphous small-to-medium sized mature B lymphocytes effacing the white pulp. The characteristic immunophenotype is positive for CD20, DBA.44 (20 to 90%), and IgG, and typically negative for CD5, CD10, CD23, cyclin D1, CD43, annexin A1, CD11c, CD25, CD123, and CD138. The Ki-67 proliferative index is characteristically low. Cyclin D3 is expressed in the majority of SDRPL in contrast with other types of small B-cell lymphomas, thus facilitating the recognition of this disease. There is no standard treatment regimen for SDRPL. Initial treatment options include splenectomy, rituximab monotherapy, or a combination of both. Chemoimmunotherapy should be considered in patients with advanced disease at baseline or progression.