A Rare Case of a Patient With Hairy Cell Leukemia Developing Blastoid Marginal Zone B-Cell Lymphoma.

There have been several case reports associating hairy cell leukemia (HCL) with non-Hodgkin's lymphoma. However, it remains unclear whether these rare phenomena represent disease transformation or the coexistence of two separate disease entities. De novo marginal zone lymphoma can be routinely seen in elderly patients; however, in a patient with a history of HCL, a transformation is more likely than de novo blastoid marginal zone lymphoma. In this report, we present a rare case of a patient with HCL developing a high-grade blastoid marginal zone B-cell lymphoma (MZBCL).