[Acute congenital monoblastic leukemia and 9;11 translocation: a case].

Acute leukemia in the newborn child is a rare event. The clinical and biological characteristics differ from those normally encountered in the older child. Tumoral syndrome and extra-medullar locations are frequently described in the literature. Many authors have noted the difficulty of diagnosis due to the immaturity of the malignant proliferation. While it is generally agreed that therapeutic abstention is justified in the leukemoid reaction in Down's syndrome, the choice is debatable in the phenotypically intact newborn. For this reason, blastic karyotype analysis is essential and may provide guidelines when considering treatment. We report on a case history of acute monoblastic leukemia with translocation 9;11 that was diagnosed at birth in a normal newborn infant. The juxtaposition of c-ets 1 protooncogene and the beta-interferon gene has been associated with this kind of cytogenetic disease and probably constitutes a model for human leukemogenesis.