SAT-463 Cyclic Cushing’s Syndrome: A Case Report and Review of Diagnostic Challenges

Abstract Disclosure: N. Chand: None. R. Yan: None. S. Cholekho: None. Introduction: Cyclic Cushing's syndrome (CCS) is a rare disorder characterized by episodic hypercortisolism alternating with normal cortisol levels, which poses significant diagnostic challenges. It mainly affects women and can lead to serious metabolic and cardiovascular issues. Understanding its cyclical nature is vital for effective management. Method: We present a case of a 47-year-old female with a history of mammary adenosis and lung adenocarcinoma who underwent extensive evaluation for suspected CCS. Results: The patient initially showed no clear signs of hypercortisolism, indicating a subtle onset of CCS. Over 12 months, she developed bilateral adrenal nodules, recurrent facial edema, and mild weight gain.Imaging revealed an irregular right adrenal gland (2.9 × 2.4 cm) and a well-defined left adrenal gland (0.8 cm). Her 24-hour urinary free cortisol (UFC) was 201.7 µg/24 hr, and a dexamethasone suppression test showed ACTH at 1.70 ng/mL and PTC at 28.60 mol/L. Cortisol and ACTH levels fluctuated during hospitalization. After diagnosis, the patient underwent laparoscopic right adrenal tumor resection, revealing a cortical adenoma. Post-surgery, she received a tapering glucocorticoid regimen for one month. Three months later, hormone levels normalized, facial swelling diminished, and her weight decreased from 62 kg to 60 kg, indicating treatment efficacy. However, ongoing monitoring is essential due to recurrence risk. Conclusion: CCS presents unique diagnostic challenges because of its variable manifestations and remission phases. Treatment must be individualized based on hormonal dynamics, with careful monitoring for relapse. The lack of standardized diagnostic criteria complicates CCS identification, highlighting the need for increased clinician awareness, especially in high-risk groups. Further research is crucial to develop effective diagnostic protocols for CCS. Keyword: Cyclic Cushing syndrome, ACTH, Dexamethasone suppression test (DST), Adrenal adenoma. Presentation: Saturday, July 12, 2025