A t(11;14)(p13;q11) specific for T-cell malignancies in acute megakaryoblastic leukemia.

A 2-year-old girl with a very rare form of acute megakaryoblastic leukemia (AMKL), having the 11p13;14q11 translocation specific for T-cell malignancies, is reported. She was diagnosed as having AMKL on the basis of her bone marrow, which contained 30% megakaryoblasts identified by characteristic morphology on May-Giemsa stain, positive for platelet peroxidase activity and for the surface marker of platelet glycoprotein IIb/IIIa, CD41. Cytogenetic studies of marrow cells revealed 47,XX,i(7q), +der(11)t(11;14)(p13;q11), -14, +21. She achieved hematologic remission after two courses of chemotherapy including behenoyl cytarabine, acracinorubicin, 6 mercaptopurine, and prednisolone, but soon relapsed and died 11 months after admission. This case suggests that adequate diagnostic assessments of morphology, surface markers, and cytogenetics are necessary for proper diagnosis in leukemia and lymphoma, and that an important, though as-yet unidentified, gene in megakaryopoiesis may reside in the 14q11 chromosomal region.