Pheochromocytoma associated with polycythemia: case report.

Secondary polycythemia has been noted in association with various neoplasms. An erythropoiesis stimulating factor (erythropoietin) has been demonstrated in the fluid or tissues obtained from most of these neoplasms and erythropoietin levels were found to be elevated in the serum and returned to normal after resection of these tumors. Recently, the potential of pheochromocytoma to produce a wide variety of hormones and neurotransmitters such as growth hormone, motilin, ACTH, atrial natriuretic factor (ANF) and others has been shown. Although elevated hematocrit has been observed in association with pheochromocytomas, the occurrence of absolute polycythemia in such cases is very rare. In this report, we describe a patient with a long history of hypertension and cardiac dysrhythmia as well as polycythemia which was secondary to pheochromocytoma. The patient's blood pressure normalized and the polycythemia regressed after resection of the tumor. Increased release of erythropoietin is the most favored explanation for this rare association. Pheochromocytoma should be included in the differential diagnosis of secondary polycythemia.