ACTH-dependent Cyclic Cushing Syndrome With Successful Pregnancy and Early Postpartum Relapse.

Cyclic Cushing syndrome (CS) is a rare form of CS characterized by intermittent episodes of hypercortisolism. We report the case of a 30-year-old female who was diagnosed with ACTH-dependent Cushing disease, confirmed by initial biochemical tests and pituitary imaging. Although surgery was planned, she experienced spontaneous remission for several months, followed by pregnancy, and subsequently relapsed in the early postpartum period. Transsphenoidal resection of a left-sided pituitary adenoma was then performed, confirming an ACTH-secreting tumor. A review of the literature revealed that this case contributes to the increasing number of patients with cyclic CS, with particular attention to the challenges of diagnosing hypercortisolism during pregnancy. While cases of Cushing disease recurrence after pituitary surgery in the immediate postpartum period have been documented, this is the first reported case of early postpartum relapse in cyclic CS. This case highlights the importance of long-term follow-up in patients with a high index of suspicion for cyclic CS, as well as the diagnostic challenges in managing the condition during pregnancy and the peripartum period.