Acute lymphoblastic leukemia followed by acute granulocytic leukemia in a pediatric patient

A 14-year-old white male patient had acute lymphoblastic leukemia characterized by a periodic acid-Schiff (PAS)-positive reaction, negative T and B cell markers, and negative nonspecific esterase and peroxidase reactions. Ten months after the initial diagnosis, the bone marrow appearance was compatible with acute granulocytic leukemia, with the presence of Auer rods, and with peroxidase-positive, nonspecific esterase-negative, and negative PAS reactions. Karyotyping and banding were not performed. The concurrence of both diseases in this patient is unique in pediatric oncology.