ACTH-producing pituitary carcinoma presenting as the cauda equina syndrome.

A 43-year-old woman presented with incontinence, weakness, and paresthesia, consistent with the cauda equina syndrome, 10 years after having a pituitary tumor surgically removed and 4 years after excision of two "meningiomas" of the cervical cord. The patient was also hypertensive and had a cushingoid habitus. Emergent surgical decompression of the spinal cord revealed intradural metastatic adrenocorticotropic hormone-producing pituitary carcinoma. Pituitary carcinomas are rare. The majority of reported cases of adrenocorticotropic hormone-producing carcinoma have exhibited metastases outside the central nervous system. To our knowledge, this represents the first case of an adrenocorticotropic hormone-producing pituitary carcinoma presenting with the cauda equina syndrome. A review of all reported cases of pituitary carcinoma indicated that central nervous system metastases were more common than metastases to distant sites, and patients with distant metastases experienced a shorter duration of disease than did those with central nervous system metastases.