The younger of two sisters (C. R. M.) died at the age of nineteen years with extensive metastases from a tumor in the lower portion of the tibia that was evidently a Ewing sarcoma. The older sister (M. J. E.) had a high humeral amputation for a tumor of the radius at the age of nineteen years. Because of its histological appearance, this tumor was at first suspected of being metastatic carcinoma. Because the patient remained well for five years, however, this notion was abandoned. During the sixth year there developed in M. J. E. a pleural and pulmonary tumor that is interpreted as a metastasis from the radial lesion. The pattern of this secondary tumor lacks epithelial features and resembles that of the younger sister's tumor. We feel that the most tenable diagnosis for M. J. E.'s tumor is that it is an unusual variant of Ewing's tumor.