Spontaneous remission of ectopic Cushing's syndrome due to pheochromocytoma: a case report.

A young female adult with Cushing's syndrome arising from ectopic production of corticotropin (ACTH) from an adrenal pheochromocytoma showed spontaneous clinical and biochemical remission of hypercortisolism after a brief period of ketoconazole administration. Despite continued remission of the hypercortisolism over the next 18 months, there was progressive catecholamine hypersecretion with significant morbidity as a result of the pheochromocytoma. Surgical resection of the left adrenal gland revealed a pheochromocytoma showing focal cytoplasmic immunostaining for ACTH and marked diffuse compact cell hyperplasia in the adrenocortical tissue. To our knowledge this is the first reported case of spontaneous clinical and biochemical remission of ectopic ACTH production from a pheochromocytoma. The pathogenesis of the remission remains unknown.