Abstract
A 56-year-old man came to our hospital with abdominal distension and pain. A swollen spleen was palpable in the left upper abdomen. Blood examination showed leukocytosis, thrombocytopenia and elevation of serum IL2 receptor, IgM and IgA. Peripheral blood smear revealed atypical lymphocytes with irregular villi on the cell surface corresponding to villous lymphocyte. CT showed a remarkably swollen spleen. FDG-PET CT showed diffuse high FDG uptake in the spleen. Bone marrow smear showed nodular proliferation of atypical lymphocytes with irregular villi on the marginal cytoplasm. Tartrate-resistant acid phosphatase staining of the bone marrow was negative. Flow cytometry of peripheral blood lymphocytes indicated positive findings for CD20 and CD11c, but negative for CD5 CD10, CD25, and CD103. From these findings, we diagnosed this case as splenic marginal zone lymphoma. Because the patient had abdominal pain and thrombocytopenia, splenectomy was performed. Histopathological finding of the resected spleen showed diffuse proliferation of small to moderate size atypical lymphocytes invading the red pulp by replacing marginal zones. SMZL is one of the low grade non-Hodgkin lymphomas; however, there have been only 9 reported cases in Japan, including the present case , which was the first case with accurate preoperative diagnosis.
