Blastic transformation of splenic marginal zone B-cell lymphoma

To our knowledge, blastic transformation of splenic marginal tone lymphoma, a recently characterized low-grade lymphoproliferative disorder, has not b een reported previously. In this regard, we report the unique case of a 70- year-old woman whose untreated splenic marginal zone lymphoma underwent bla stic transformation 3 years after diagnosis. Her hematologic medical histor y started in 1988 as thrombocytopenia refractory to steroids associated wit h atypical lymphoid infiltrate in the bone marrow. She underwent splenectom y in 1989, which revealed splenic marginal zone lymphoma. One year later, t he patient developed lymphadenopathy noted in the chest, axillary, abdomina l, and retroperitoneal lymph nodes. Because she was asymptomatic, treatment was limited to a conservative supportive regimen. The nodal lymphoma cells had features associated with marginal zone lymphoma and expressed B-cell m onotypic kappa light chain. She was readmitted for the last time 2 years la ter with findings of 16% blasts in the peripheral blood and massive infiltr ation of the bone marrow by large blastoid cells. The blasts showed dispers ed chromatin and prominent nucleoli, and possessed a moderate amount of cle ar cytoplasm. The blasts, like the previous nodal and splenic lymphomas, ha d a CD20-, CD19-, IgM-positive phenotype, but lacked reactivity for CD5, CD 10, and CD23. The patient displayed clinical remission after treatment with vincristine and prednisone, but died of aspiration pneumonia 1 month later . These observations suggest that, similar to the other low-grade lymphopro liferative disorders, an untreated splenic marginal zone lymphoma may under go high-grade blastic transformation.