Waldenström Macroglobulinemia and Chronic Myelomonocytic Leukemia: Case Report and Literature Review.

As hematological tumor patients are surviving long-term, the long-term toxicities of therapeutic regimens have become increasingly evident. The coexistence of two hematological tumors in the same patient is extremely rare and typically shows an aggressive clinical course and unsatisfactory prognosis. In the present case, we describe the case of a 64-year-old man who was admitted to the hospital because of fatigue. Biochemical showed an elevated monoclonal immunoglobulin M (IgM) at 37g/L. Next Generation Sequencing (NGS) analysis revealed MYD88^L265p mutation, CXCR4 wild type. In August 2020, he was diagnosed with Waldenström macroglobulinemia (WM) and underwent six cycles of chemotherapy with bendamustine, zanubrutinib, and rituximab. However, he was admitted to the hospital in December 2022 following six-month history of Leukocytosis. Bone marrow (BM) flow cytometry (FCM) showed increased MO1 monocytes. Molecular studies were positive for TET2 mutations. He was finally diagnosed with WM and chronic myelomonocytic leukemia (CMML). Then he accepted hematopoietic stem cell transplantation (HSCT). Unfortunately, after 6 months, the patient died as a consequence of severe pulmonary infection.