Calla positive acute lymphoblastic leukemia after etoposide-based therapy for Ewing's sarcoma

This is an unusual and interesting case report concerning a 10 year old boy with an initial diagnosis of Ewing's sarcoma of the right tibia. He was successfully treated with a chemotherapy regimen consisting of vincristine, cyclophosphamide (cumulative dose 7200 mg/m2), doxorubicin, etoposide (cumulative dose 2700 mg/m2) and cisplatin and local radiotherapy to the tibia. After an interval of 37 months he developed CALLA positive acute lymphoblastic leukemia with 11q23 chromosomal abnormality. The possible roles of etoposide and cyclophosphamide are discussed.