Although the number of authenticated case reports of primary tumors of the heart and pericardium now approximates 200, the number of primary sarcomas of the pericardium described in the literature is still small. Yater,1writing in 1931, collected reports of ten cases of primary sarcoma of the pericardium. The present case adds one more to the literature. Pericardial sarcomas may be divided into two general groups, the one, such as that described by Williams,2being limited to the pericardium without invasion of the heart; the other, such as that described by Hill,3infiltrating the heart tissue. The case to be reported is of the former type. A review of our case with the changes found at necropsy is given here. REPORT OF CASE History. —C.F., a white man, aged 47, admitted to the Medical Service of City Hospital, March 1, 1933, complained chiefly of shortness of breath.