Follicular lymphoma with blastic conversion: a report of two cases with confirmation by immunoperoxidase studies on bone marrow sections.

Two cases of low-grade follicular lymphoma are presented in which evolution to a blastic phase with marrow and peripheral blood involvement occurred. One case was a follicular and diffuse mixed-cell lymphoma, while the second was a follicular and diffuse small cleaved-cell lymphoma. In both cases, at two and three years after initial presentation, a clinical picture resembling acute leukemia developed, with immature blastic-appearing infiltrates in the bone marrow and circulating blastic cells. Immunoperoxidase studies on fresh frozen sections of bone marrow in both cases confirmed the B-cell nature of the infiltrates and excluded the clinical impression of acute non-lymphocytic leukemia. The differential diagnosis of hematolymphoid infiltrates in the bone marrow in patients with follicular lymphoma is discussed.