Based on study of 58 histologically proved cases of SMCD, we believe that the prognosis of most SMCD patients can be anticipated at the time of initial diagnosis by using 5 independent significant predictors developed in a multivariate model. Our study confirms the significance of several previously reported poor prognostic factors: absence of skin involvement and the presence of hepatosplenomegaly, cytologic atypia, and a hypercellular bone marrow. However, in contrast to previous reports we did not find a uniform correlation between the presence or absence of skin involvement and prognosis. The observation that anemia was strongly related to so many prognostic variables may be due to the number of patients in our study with associated hematologic disorders. Alternatively, this evidence of ineffective erythropoiesis may support the concept that SMCD is a myeloid stem cell disorder and frequently affects other hematopoietic cell lines. The observation that death occurs within the first 3 years in most fatal cases of SMCD suggests that these patients should be followed carefully for this interval after initial diagnosis, especially if poor prognostic features are present. Currently there is no curative therapy for SMCD.