RESUMEN
Three cases of secondary (therapy-related) hematologic malignant conditions were identified among 95 children as old as 18 years of age; the cases were diagnosed between 1984 and 1990 and consisted of acute lymphoblastic leukemia, acute myeloid leukemia (AML), and myelodysplastic syndrome (MDSs). They constituted 10% of all new cases of AML and MDS seen at the University Hospitals of Cleveland during this time and were not related to congenital factors. The primary malignant conditions were malignant thoracopulmonary tumor (Askin tumor), neuroblastoma, and Burkitt's lymphoma. The secondary hematologic disorders all showed a prominent monocytic component: acute monocytic leukemia, MDSs evolving to acute myelomonocytic leukemia, and chronic myelomonocytic leukemia. The mean interval between treatment for the primary malignant condition and the onset of secondary disease was 36 months. All had received cyclophosphamide and an epipodophyllotoxin for the primary tumor; two were treated with radiation therapy. Cytogenetic abnormalities included del(5), del(13), t(1;6), and t(9;11)(p22[symbol:see text]3). The survival time after the onset of secondary disease was short.