Recurrent Cushing's disease after transsphenoidal surgery.

Thirty-four patients with proven Cushing's disease underwent transsphenoidal surgery between January 1976 and August 1988. Postoperatively, all the patients had biochemically proven remission. Seven patients who had recurrence of their disease (incidence, 20.6%) were evaluated clinically and biochemically and the results are presented. All of seven patients had surgically and pathologically proven pituitary adenomas. All of seven patients had postoperative adrenal insufficiency necessitating steroid replacement for a mean of 8 months. The time of recurrence varied widely and ranged from 29 to 62 months, with a mean of 40 months. We conclude that (1) the longer the period of follow-up, the higher the incidence of recurrence; (2) although the recurrence rate is low (20.6%), it is certainly appreciable; and (3) the time of recurrence can be delayed (62 months) and thus we recommend yearly follow-up with urinary free cortisol determinations.