CLINICAL HETEROGENEITY OF ECTOPIC ACTH SYNDROME: A LONG-TERM FOLLOW-UP STUDY

Objective: Ectopic adrenocorticotropic hormone (ACTH) syndrome (EAS) is a heterogeneous condition caused by neuroendocrine neoplasms (NENs) located in the lungs, thymus, or pancreas. Our purpose was to evaluate the long-term outcome of these patients. Methods: Retrospective study at a referral center. The charts of 164 patients with Cushing syndrome, followed at our center from 1993 to 2019, were analyzed. Results: EAS was found in 16 patients (9.75%, 9 women, mean age 36.01 years) who had been followed for a median of 72 months. The source of EAS was a NEN in 10 patients (8 bronchial and 2 thymic carcinoid tumors) and a mixed corticomedullary tumor, consisting of a pheochromocytoma and an adrenocortical carcinoma in 1 patient. In 2 of the 6 patients initially considered to have occult EAS, the source of the ACTH excess became apparent after adrenalectomy, whereas in the remaining 4 (25%) patients, it has remained occult. Of the 11 patients in whom resection of the NEN was attempted, 10 patients achieved an early remission (91%), but 4 (25%) of these patients had a recurrence during follow-up (biochemically and clinically silent in 2 patients). Three patients died (18.75%): the young woman with the mixed corticomedullary tumor, a man with a thymic NEN that evolved into a neuroendo- crine (NE) carcinoma after 11 years of follow-up, and a woman with a bronchial NEN. Conclusion: The course of EAS varies according to tumor type and grade. Some patients have a protracted course, whereas others may evolve into neuroendocrine carcinomas.