The fortuitous diagnosis of Burkitt lymphoma in a patient with chronic myelomonocytic leukemia

Abstract

An 83-year-old woman had been under regular follow-up for 10 years with a diagnosis of chronic myelomonocytic leukemia (CMML) when a blood count showed that her hemoglobin concentration (Hb) had fallen by 20 g/l. There were no other unexpected findings on physical examination or in the blood count or film. Bone marrow aspiration was performed to investigate the fall in Hb. Aspirate films showed monocytosis and neutrophil dysplasia. However, unexpectedly, they also showed a population of medium-sized blast-like cells with strongly basophilic, heavily vacuolated cytoplasm, comprising a third of bone marrow cells (top left and right). Flow cytometric immunophenotyping showed expression of CD19, CD20, and CD79b with lambda light chain restriction. CD34 was negative. Staining for Ki-67 showed a very high proliferation fraction (bottom left). Myeloid blast cells expressing CD34, CD13, and CD33 were <1%. A diagnosis of Burkitt lymphoma was made, a very unexpected finding in an elderly woman with CMML with no cause for concern other than a fall in the Hb. Twenty days later Burkitt lymphoma cells appeared in the peripheral blood (bottom right).