Cytogenetic and molecular characterization of T-cell acute lymphoblastic leukemia as a second tumor after anaplastic large-cell lymphoma in a boy.

We report a case of acute T-cell lymphoblastic leukemia which developed in a boy 8.5 years after successful treatment for anaplastic large-cell lymphoma. Cytogenetic and molecular characterizations of the second tumor were performed. The cytogenetic investigation revealed a complex pattern of karyotypic alterations, including double minutes, ring chromosomes, and a duplication of the p21-32 region of chromosome 1. The microsatellite DNA analysis excluded rearrangement or deletion of the TAL1 gene in the tumor cells; rearrangements of the MLL gene were excluded by Southern blot analysis. To the best of our knowledge, this is the first report of T-cell lymphoblastic leukemia arising after treatment of CD 30+ anaplastic large-cell lymphoma. The different T-cell receptor rearrangement evidenced in the two tumors indicates that this second malignancy most likely emerged de novo, but was plausibly related to the previous radiation and chemotherapy.