Experience in investigating splenic red pulp lymphoma

Aim. To generalize hematologists’ experience of the diagnosis and differential diagnosis of splenic red pulp lymphoma (SRPL). Materials and methods. Eighty-seven splenic biopsy specimens taken from patients with different B-cell lymphoproliferative diseases were examined in the Hematology Research Center in 2013—2014. The diagnosis of SRPL was based on the morphological, immunohistochemical, immunophenotypic, and molecular examinations of the splenic biopsy specimens, blood and bone marrow (BM) tests in 4 (4.6%) cases. Results. There was significant splenomegaly in all SRPL cases, lymphocytosis in 56 to 94% (leukocytes, 55 and 75·109/l in 2 cases), circulation of hairy lymphocytes with the phenotypes CD20+ (markedly), CD11c+/±, CD103+/± (weakly), LAIR-1+, CD25–, CD5–, CD10–, and CD23–, which did not contain tartate-resistant acid phosphatase, without BRAFV600E mutation, BM with insignificant lymphoid infiltration of CD20+, CD25–, Annexin 1–, and Cyclin D1–. The weight of the spleen averaged 3900 g (1450-9500 g); its tissue exhibited lymphoid infiltration of the red pulp with the phenotypes CD20+, DBA.44+, CD25–, Annexin1–, Cyclin D1–, CD103–, CD123–, CD27–, focal СD11c±, and TRAP±. Four patients (2 after splenectomy (SE) and 2 after SE and chemotherapy with cladribine and rituximab) are being followed up in remission. Conclusion. SRPL is a rare disease that should be presumed to be in significant splenomegaly and lymphocytosis with hairy lymphocytes, which have only some markers for classical hairy cell leukemia (HCL), in minor BM lesion. SE is the standard for diagnosis and treatment. The differential diagnosis of SRPL with HCL has clear criteria and that with HCL-v is undetected.