1992 Volume 33 Issue 12 Pages 1851-1856
A 56-year-old man had a leiomyosarcoma of the small intestine in 1987. After surgery, he received cyclophosphamide for 2years. In December, 1990, he exhibited severe pancytopenia. His hematological data were as follows: Hb 7.4 g/dl, ret. 0.8%, WBC 1,700/μl with leukoerythroblastosis and 2.8×104/μl platelets. A bone marrow aspiration was a dry tap. A bone marrow biopsy specimen showed a hypercellular marrow with myelofibrosis, leukemic infiltration (10.2%) and slight dyserythropoiesis. Both PPO and GPIIb/IIIa reaction were positive for blast cells and atypical megakaryoblasts. A diagnosis of MDS with an abnormality in megakaryocytic lineage was made. The patient was treated with 1,25-dihydroxy-vitamin D3, however this therapy was temporary and he developed into acute megakaryoblastic leukemia (M7). This report suggested that some cases of therapy-related leukemia (TRL) mainly involve megakaryocytic lineage and are diagnosed as MDS with myelofibrosis which transform to M7. The fact that PAS stain of erythroblasts in the patient reported here was positive may suggest involvement of a stem cell capable of aberrant differentiation along each of these pathyways. In the near future, the development of more precise immunological markers of differentiation and EM study will permit better diagnosis of TRL and may therefore facilitate new therapeutic approaches.
