Ring chromosome in a case of acute myelomonocytic leukemia: its significance and a review of the literature.

The presence of ring chromosomes is a rare finding in patients with de novo acute nonlymphocytic leukemia (ANLL). In this report we describe the cytogenetic abnormalities, including ring chromosomes, of a 45-year-old white male who had ANLL of the myelomonocytic type (M4). All of the leukemic cells had both a small unidentified ring and a medium-sized ring which was derived from chromosomes 2 and 11, r(2;11)(2p25;11p15q23;2q37). Four different types of rings or other structural abnormalities were derived from this medium-sized ring. A review of the literature indicated that the median survival of ANLL patients with either identified or unidentified ring chromosomes was 5 to 6 months, and that the presence of these cytogenetic abnormalities was related to a poor prognosis.