Myelomastocytic leukemia: myeloid neoplasm characterized by partial differentiation of mast cell-lineage cells.
A novel subtype of myeloid leukemia exhibiting a partial differentiation of mast cell-lineage cells is described. The disease is characterized by an increase in myeloblasts as well as an increase in immature (blast-like) metachromatic cells (>10% in bone marrow or blood smears). Metachromatic cells express KIT (CD117) and tryptase, but lack basophil-related antigens. In contrast to mast cell leukemia/systemic mastocytosis, metachromatic cells do not express CD2 or CD25, do not form multifocal dense aggregates in the bone marrow, and do not exhibit transforming mutations at codon 816 of c-kit. In the few patients recorded so far, a complex karyotype without recurring anomaly was found. The prognosis appears to be grave, although complete remission in response to chemotherapy has been described.
Valent
Peter
P
Department of Internal Medicine I, Division of Hematology and Hemostaseology, University of Vienna, Austria. peter.valent@akh-wien.ac.at
Samorapoompichit
Puchit
P
Sperr
Wolfgang R
WR
Horny
Hans-Peter
HP
Lechner
Klaus
K
D002454:Cell Differentiation; D019070:Cell Lineage; D003937:Diagnosis, Differential; D006801:Humans; D007951:Leukemia, Myeloid / Q000145:classification* / Q000175:diagnosis / Q000473:pathology*; D008407:Mast Cells / Q000473:pathology; D008415:Mastocytosis / Q000175:diagnosis / Q000473:pathology*; D011379:Prognosis