Late complications in remission from Cushing disease. Recurrence of tumor with reinfarction or transformation into a silent adenoma.

Two of 4 patients who underwent spontaneous remission from Cushing disease (CD) demonstrated regrowth of the pituitary adenoma 2 and 5 years later. In the first patient, the recurrent tumor also secreted corticotropin, with subsequent relapse of fulminant cushingoid features. However, after 14 more months, it again became infarcted, and the patient underwent complete clinical remission, which has persisted for about 3 years. In the second patient, the regrowth of the tumor occurred silently, as no clinical cushingoid features or rise in cortisol levels were noticed. Because of its size, the tumor was resected and found to have immunoreactivity for corticotropin (silent corticotroph adenoma). About 4 years after the first operation, a second surgical procedure was performed because of massive regrowth of the tumor. Again, there was no concomitant elevation of cortisol levels or endocrinologic symptoms. This time, the tumor did not even stain for corticotropin. While spontaneous remission in CD is rare, recurrence is even rarer. Reremission of CD and the change from a corticotropin-secreting adenoma to a silent one are described herein for the first time (to our knowledge). These cases demonstrate that patients with CD have to receive careful follow-up, even if they undergo remission, and that the long-term outcome of such remission is unpredictable.