Prolymphocytic transformation of lymphoplasmacytic lymphoma: an extremely unusual event.

Although rare cases of prolymphocytic transformation from splenic B-cell lymphomas and follicular lymphoma have been reported, prolymphocytic transformation from lymphoplasmacytic lymphoma has not been previously reported. We report a case of 76-year-old-male patient with a history of Waldenström macroglobulinemia diagnosed in 2010 and treated with infusion chemotherapy. He was in clinical remission for 5 years. In 2016, he presented with diffuse lymphadenopathy, and a head and neck lymph node biopsy showed lymphoplasmacytic lymphoma. MYD88 mutation was detected by polymerase chain reaction. A subsequent bone marrow biopsy showed B-cell lymphoma with increased prolymphocytes. Peripheral blood showed numerous circulating prolymphocytes. MYD88 was detected by polymerase chain reaction in the bone marrow. Cerebrospinal fluid was positive for lymphoma cells with prolymphocytic morphology. An IgM κ paraprotein was noted by immunofixation performed on the patient's serum, urine, and cerebrospinal fluid. The patient was resistant to chemotherapy, developed multiorgan failure, and died shortly thereafter.