Simultaneous occurrence of polycythemia vera and Waldenstrom macroglobulinemia: a case report and review of the literature.

Polycythemia vera and lymphoproliferative disorders can occur simultaneously. Lymphoproliferative disorders reported to occur simultaneously with polycythemia vera include chronic lymphocytic leukemia (CLL), non-Hodgkin's lymphoma (NHL), and acute lymphoblastic leukemia (ALL). Different theories have attempted to explain this occurrence. Some implicate a common cell of origin to the two disorders, others include chance alone, yet others implicate an underlying humoral or immune mechanism caused by the first disorder leading to a second clonal expansion. We report the first case of polycythemia vera with a simultaneous diagnosis of Waldenstrom macroglobulinemia, and we review the literature trying to explain this unusual occurrence.