Endocrine Abstracts

Introduction: We present a case of probable cyclical Cushing’s syndrome (CS) masquerading as polycystic ovarian syndrome (PCOS) which went undetected for almost a decade. Our case highlights the subtleties and complexities of interpreting diagnostic tests in patients with cyclical endogenous hypercorticolism.

Case: A 33-year old female with presumed PCOS presented with a seven year history of persistent hirsutism and acne. However there was no menstrual disturbance and she had two spontaneous pregnancies. She worked as an advisor for a Slimming Company and reported that both weight and hirsutism fluctuated significantly in a cyclical fashion despite a healthy lifestyle.

Investigations: On presentation BMI was 28 kg/m² without marked truncal obesity. Blood pressure was 132/90 mmHg and there were no other clinical stigmata of hypercortisolaemia. The diagnosis of PCOS was revisited and CS was queried in view of the absence of menstrual disturbance and fluctuating weight-gain. 17-OHP and serum testosterone was normal. 24-hour urinary free cortisol excretion was raised at 221 (normal<200 nmol/24 h). 48 hr low dose Dexamethasone suppression test (DST)showed non suppression of cortisol (Baseline 430 nmol/l; 48 hr 156 nmol/l) confirming endogenous hypercortisolaemia. There was also disruption of diurnal cortisol variation(Midnight cortisol 538 nmol/l). High dose DST suppressed cortisol to 51 nmol/l confirming ACTH dependent CS(ACTH 28 ng/L; normal 0.1 to 47.0). Pituitary MRI demonstrated an 18×10 mm adenoma with cystic degeneration. Transphenoidal pituitary surgery was undertaken without complications and was curative.

Conclusion: Cyclical CS is a rare entity and often misdiagnosed. Cyclical manifestation of the pathognomonic signs and symptoms of hypercortisolism are suggestive of the diagnosis and endocrine testing during symptoms may aid the diagnosis. PCOS shares common symptoms with CS like hyperandrogenism and weight gain and is often over diagnosed by non-specialists. A high index of suspicion remains the cornerstone of diagnosis.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.