Cushing's syndrome manifesting as pseudo-central hypothyroidism and hyperosmolar diabetic coma

To report an unusual case of Cushing's syndrome caused by an adrenal pheochromocytoma, manifesting as pseudo-central hypothyroidism and diabetic hyperosmolar coma. A detailed case report is presented, including clinical, laboratory, and radiologic findings as well as results of selective adrenal vein sampling. In a 69-year-old woman with weight gain and hypothyroidism, diabetes mellitus with hyperosmolar coma developed precipitously. She had mild hypertension, but no diabetes was noted 2 weeks before the hyperosmolar event. Evaluation revealed Cushing's syndrome due to ectopic secretion of adrenocorticotropic hormone from an adrenal pheochromocytoma. After surgical resection of the tumor, the diabetes and the hypertension resolved. Furthermore, the pseudo-central hypothyroidism was eliminated, but primary hypothyroidism was unmasked. This combination has not been reported previously. This case illustrates the array of endocrinopathies that can be associated with pheochromocytoma, causing Cushing's syndrome.