A Case of Pure Red Cell Aplasia which Progressed to Acute Myelomonocytic Leukemia after 8 Months

Abstract

A 56-year-old male was first examined at the Toho University Hospital because of anemia. He had a prolonged history of exposure to organic solvents until 2 years before admission. No hepatosplenomegaly was found. Blood examination revealed severe anemia, but no leukopenia or thrombopenia. Reticulocyte count was 0.1%. Bone marrow was normocellular but there was a complete depletion of all erythroid elements. A diagnosis of pure red cell aplasia was made. Basophilia and eosinophilia were observed. Serum erythropoietin level was normal. No thymoma was found. Serum vitamin B₁₂ level was elevated. Opportunistic infections occurred in spite of normal leukocyte count. Blasts first appeared in peripheral blood samples taken on his 95th day of hospitalization, and thrombocytopenia gradually developed. He was readmitted to our hospital because of a nasal phlegmon 8 months after his first admission. At that time leukemic cells were found in his bone marrow (28.8%) and peripheral blood (9.0%). Based on the low percentage of leukemic cells, hypocellular bone marrow and cytochemical findings, we diagnosed the patient's condition to be hypoplastic acute myelomonocytic leukemia. Chromosome abnormalities appeared at this stage. After antileukemic treatment he died of pneumonia.
Cases such as this one, (the 2nd case in Japan) showing pure red cell aplasia during the preleukemic state and progressing to acute leukemia after 8 months, are rare.