Coexistence of somatostatin-immunoreactivity in an adrenal pheochromocytoma and a thyroid medullary carcinoma (Sipple syndrome).

The presence of somatostatin-immunoreactivity in tumor tissue of adrenal pheochromocytoma and thyroid medullary carcinoma identified by peroxidase-antiperoxidase technique is reported in one case of Sipple syndrome. This patient was found to have a high concentration of somatostatin-immunoreactivity in the peripheral blood (40 ng/l, normal 0-20 ng/l). After removal of the tumors, the plasma somatostatin-immunoreactivity fell within normal range (12.5 ng/l). This seems to be the first report of Sipple syndrome that produces somatostatin-immunoreactivity in both: pheochromocytoma and thyroid medullary carcinoma.