A case of myelodysplastic syndrome (MDS) complicated by malignant lymphoma is reported. The patient was a 68-year-old male who was admitted to hospital with severe anemia and was diagnosed as having MDS on the basis of hematological examinations and the findings of bone marrow biopsy. Treatment with steroid hormones, anabolic hormone preparations, and blood transfusion proved unsuccessful and he died of infection six months later.
At autopsy, the bone marrow was hypoplastic and blast cells showed very poor differentiation, the megakaryocytes were decreased in number, and the erythroblasts had abnormal nuclei. Systemic lymphadenopathy (paratracheal, mesenteric, parapancreatic and paraaortic) was found. Histological examination of the lymph-nodes revealed diffuse proliferation of medium sized lymphocytes which had B cell markers and showed plasmacytoid differentiation.
The starry sky constellation of large mononuclear phagocytes in the lymphoma tissue was quite similar to the histology of Burkitt's lymphoma. There was evidence of generalized cryptococcosis and candidiasis. Malignant lymphoma complicating MDS is very rare, but the exsistence of this case suggests that a clonal abnormality of the pluripotent hematopoietic stem cells occurs in MDS.
