Acute myelomonocytic leukemia with involvement of eosinophils and inversion of chromosome 16.

A case of acute nonlymphocytic leukemia (ANLL) with abnormal marrow eosinophils is presented. Thorough morphological, cytochemical, and cytogenetic studies confirm the existence of a recently defined new cytogenetic-morphological entity: acute myelomonocytic leukemia with abnormal bone marrow eosinophils (FAB M4), chloracetate esterase- and periodic acid-Schiff-positivity of eosinophilic granules, and pericentric inversion of chromosome 16, in this case combined with trisomy 8. So far 18 such cases have been reported from a single institution. The implications of this new association on the diagnosis of acute leukemia with abnormal eosinophils are discussed.