RESUMO
Splenic marginal zone lymphoma (SMZL) is a rare B-cell neoplasm characterized by massive splenomegaly, moderate lymphocytosis, bone marrow intrasinusoidal involvement of lymphocytes and a relatively indolent course. We report a case of SMZL diagnosed by bone marrow studies using immunophenotyping and immunohistochemical stain, and confirmed by splenectomy. The patient was a 61-year old male, who showed mild lymphocytosis in peripheral blood and bone marrow aspirates. Immunophenotyping of bone marrow aspirates showed lymphocytes positive for CD19, CD20, CD22 (dim), CD23 (dim) and negativie for CD5 and CD10. The immunohistochemistry of bone marrow and spleen also showed lymphocytes positive for CD20 and negative at for cyclin D1. Now he is being treated for chronic obstructive pulmonary disease and will receive chemotherapy.