Blastic transformation of mantle cell lymphoma.

In contrast to chronic lymphocytic lymphoma and low-grade follicular lymphomas, mantle cell lymphoma, formerly known as intermediate lymphocytic lymphoma, rarely transforms histologically into large cell lymphoma. Because of its rarity, little information is available on the prognostic or therapeutic implications of histologic transformation of mantle cell lymphoma to a "blastic" form. Here we report a case of a 68-year-old man whose mantle cell lymphoma transformed into a high-grade lymphoma with blastic cytology, which was associated with an extremely rapid clinical course. Flow cytometric analysis revealed the immunophenotype of the original lymphoma, which had typical mantle cell morphology, and the subsequent bone marrow aspirate was virtually identical, as was the immunophenotype of the small cells versus the blastic cells in the subsequent specimen. The rapid clinical course in the patient reported here is similar to that of other rare cases reported and suggests that mantle cell lymphoma in blastic transformation appears to be a very aggressive lymphoma with a clinical course similar to that of other low-grade lymphomas in histologic transformation.