Nelson's syndrome: case report and review of the literature.

A patient who developed a pituitary tumor after adrenalectomy for Cushing's disease (Nelson's syndrome) is presented. The literature reviewed shows less than a 10 percent incidence of this disorder for which extremely elevated plasma ACTH levels are diagnostic. Special radiologic technics may be required to detect small pituitary tumors, but pituitary hormone levels may be elevated in the cerebrospinal fluid if there is suprasellar tumor extension. The different modalities available for treatment of Nelson's syndrome are discussed.