A variant myelodysplastic syndrome with multilineage Pelgeroid chromatin.

An unusual myelodysplastic syndrome with similar features in two patients is described. The entity is characterized by a maturation arrest at the myelocyte stage, strikingly clumpy chromatin, and a clinical course marked primarily by difficulties caused by anemia and thrombocytopenia. Electron microscopic description of the characteristic abnormal clumpy chromatin cells is included. While the disorder is unquestionably a myelodysplastic syndrome, it is clearly distinct from chronic myelogenous leukemia, chronic myelomonocytic leukemia, and the spectrum of refractory anemias with excess blasts.