IN AN EARLIER report of 56 cases of angiosarcoma and Kaposi's sarcoma from the Memorial Cancer Center, one of us (G. P.) commented on the histopathologic significance of the coexistence of Kaposi's sarcoma and lymphoblastoma in the same patient.1 A total of seven such cases of Kaposi's sarcoma collaterally existing with Hodgkin's disease,* leukemia,† myelogenous leukemia,7 and mycosis fungoides8 have been described in medical literature. We are presenting three additional cases from the Memorial Cancer Center in which we have observed the concomitant occurrence of Kaposi's sarcoma and lymphoblastoma. In two patients, Kaposi's sarcoma and giant follicular lymphoma (Brill-Symmers disease) occurred concurrently, a combination to our knowledge not previously described. The third patient had a combined diagnosis of Kaposi's sarcoma and malignant lymphoma. The fourth patient, who at the onset of her disease had the microscopic picture and clinical findings simulating Hodgkin's disease,