Three patients with multiple myeloma developing secondary lymphoblastic leukemia: case reports and review of the literature.

Introduction: Secondary lymphoblastic leukemia has been rarely reported in patients with multiple myeloma.

Case Reports: We report 3 cases of secondary lymphoblastic leukemia in multiple myeloma patients. They shared a similar phenotype of myeloma cells and secondary lymphoblasts. The chemotherapy treatments in the 3 patients were complex due to various factors.

Conclusions: Multiple immune defects caused by exposure to a variety of agents can play an important role in the development of secondary lymphoblastic leukemia. Microscopic morphology and flow cytometry are important means to detect secondary malignancies in multiple myeloma. Further clinical, experimental and genetic studies of secondary malignancies in multiple myeloma will be necessary in the future.