Richter's syndrome with identification of marker chromosomes.

A case is presented of a man with Richter's syndrome with diffuse histiocytic lymphoma following a ten-year history of untreated chronic lymphatic leukemia. He did not respond to therapy. The lymphoma cells had 61 chromosomes with aneuploidy of 13 chromosomes and 11 structurally altered chromosomes. Only chromosomes 8, 9, 12, 14, and 18 were diploid and without abnormality. Significantly, part of chromsome 1q was duplicated as in the partial trisomy of 1q reported to characterize a number of hematologic neoplasms. A large marker chromosome with subterminal centromere was a tandem duplication of chromosome 4q.