Pheochromocytoma producing multiple vasoactive peptides.

Pheochromocytomas may produce several vasoactive peptides. We studied a 39-year-old man who presented with paroxysmal flushing and abdominal pain with normal blood pressure. Laboratory and radiologic studies established the diagnosis of right adrenal pheochromocytoma, and histologic and ultrastructural examination showed the tumor to be a typical pheochromocytoma. Tissue culture yielded large quantities of norepinephrine and epinephrine. However, immunohistochemical studies, tissue assays, and in vitro cultures documented production of several peptides, including calcitonin gene-related peptide and vasoactive intestinal polypeptide in tumor cells. The patient has been asymptomatic after tumor resection. Production of multiple peptides by this tumor may account for the flushing and lack of hypertension, despite elevated catecholamine levels in this patient.