Intrasinusoidal bone marrow infiltration: a possible hallmark of splenic lymphoma.

A particular type of lymphomatous bone marrow infiltration defined as intrasinusoidal and occurring in seven patients with splenomegaly and mild to moderate thrombocytopenia is reported. Immunocytochemistry highlighted the intrasinusoidal pattern and showed a mature B-cell phenotype. Four patients underwent splenectomy and a diagnosis of splenic marginal cell lymphoma was made. The disease course seems to be chronic and quite indolent. All patients are alive and well; follow-up ranges from 2 to 42 months. The value of bone marrow biopsy as a primary diagnostic tool in splenic marginal zone lymphomas is discussed.