Lymphome à cellules de la zone marginale splénique

Splenic marginal zone lymphoma (SMZL) is a rare B-cell lymphoma, well defined according to the 2016 WHO classification of tumors of the hematopoietic tissue, which can raise diagnostic problems. We report the case of a 72-year old patient, hospitalised for exploration of a massive splenomegaly confirmed by computed tomography (CT). Laboratory tests were normal. The patient underwent splenectomy. Microscopic examination of the surgical specimen showed widespread lymphomatous proliferation in small cells associated with CD20 marker. CD 5 and CD 43 were negative. The diagnosis of SMZL was retained. SMZL accounts for less than 2% of non-Hodgkin lymphomas. It affects subjects older than 50 years, and it is usually characterized by the presence of a massive splenomegaly without lymphadenopathies. Blood count shows inconsistent presence of villous lymphocytes in three quarters of cases. The diagnosis is essentially based on anatomopathological evaluation and shows constant nodular involvement or sometimes diffuse involvement of white pulp of the splenic parenchyma.Tumor cells are small in size with B lymphoid markers expression: CD19, CD20, CD22, CD79. They are negative for CD5, CD10, cyclin D1 and CD43. No specific cytogenetic abnormality in SMZL has been identified. SMZL is an indolent lymphoma whose treatment is not codified, depending on prognostic factors. Mortality is related to the risk of its transformation to large cell lymphoma.