title: Acute megakaryocytic leukemia with myeloid/monocytic differentiation.
abstract: Acute megakaryocytic leukemia is a rare form of acute nonlymphocytic leukemia that occurs with increased frequency in patients with Down's syndrome. Herein, we report a child with Down's syndrome who presented with a large retroperitoneal mass due to acute megakaryocytic leukemia. Immunohistochemical stains of the tumor cells also demonstrated evidence of myeloid/monocytic differentiation, with positivity for alpha-1-antitrypsin, alpha-1-chymotrypsin, and lysozyme. The significance of this phenotypic heterogeneity is unclear and awaits further studies of similar cases.
authors: Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha.
authors: J F
authors: JF
authors: Vago
authors: D D
authors: DD
authors: Weisenburger
mesh_terms: D000208:Acute Disease; D001773:Blood Cells / Q000473:pathology; D001853:Bone Marrow / Q000473:pathology*; D002454:Cell Differentiation; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D009000:Monocytes / Q000473:pathology*; D013920:Thrombocythemia, Essential / Q000276:immunology / Q000473:pathology*