Hematologic manifestations and etiology of atrial myxoma.

We have investigated the case of a woman, 44 years of age, who presented with erythrocytosis, thrombocytopenia and a right axial myxoma. Surgical removal of the tumor allowed correction of all hematologic abnormalities. A serum erythropoietin level obtained from the right atrium of the patient during pre-operative cardiac catheterization was twice those of 4 control patients (250 MIU vs. 131 MIU). Renal vein erythropoietin levels were normal. This implicates atrial myxomas as another tumor capable of erythropoietin production, and explains the heretofore mysterious polycythemia frequently reported to be associated with this tumor.