Chimeric del20q in a case of chronic neutrophilic leukemia

Chronic neutrophilic leukemia (CNL) is a rare myeloproliferative disorder i n which recurrent abnormalities of chromosome 20 have been reported. We rep ort the case of a 76-year-old woman with CNL with partial deletion of the l ong arm of chromosome 20 in a subset of bone marrow metaphases, suggesting coexistence of a clonal stem cell disorder and normal hematopoiesis. Review of the literature suggests that such mosaicism is common in CNL, possibly accounting for the favorable prognosis observed in many patients with this disorder. (C) 2000 Wiley-Liss, Inc.