Monoblastic transformation in chronic myelogenous leukemia: presentation with massive hepatic involvement.

Monoblastic transformation developed in a 26-year-old white man with chronic myelogenous leukemia and was manifested by acute, fulminant hepatic failure due to massive blastic infiltration of the liver. The hepatic failure responded dramatically to radiation therapy. The monocytic origin of the blasts was confirmed by means of light and electron microscopic examination and cytochemical studies. Cytogenetic studies of the leukemic blasts revealed a Philadelphia-chromosome-positive karyotype and a clonal evolution of chromosome changes resulting in multiple karyotypes.