8014 Cushing’s Syndrome: Two Sides of The Spectrum

Abstract Disclosure: M. Aguilera: None. A. Vu: None. J. Shakil: None. R. Al-Ward: None. Introduction: Cushing’s syndrome (CS) is a rare condition with an annual incidence of 2-8 per million. Endogenous CS is mainly due to corticotroph adenoma of the pituitary followed by excessive glucocorticoid production from adrenal and ectopic sources. CS has significant morbidity and mortality hence the need for timely diagnosis. The varied presentations often pose great challenges in identifying the source of hypercortisolism. We present two unusual cases of CS with distinct clinical presentations and atypical laboratory profiles. Case 1: 25-year-old male with no medical history presented with 9 months of facial puffiness, weight gain, fluid retention, hypertension and blurred vision. Physical examination revealed round facies, bilateral supraclavicular fat pads and wide abdominal striae. Laboratory workup showed markedly elevated ACTH 537 pg/mL [7.2-63 pg/mL], serum cortisol 8.5 ug/dL [6.2-19.4 ug/dl], 24-hour urine free cortisol (UFC) 30 [5-62 ug/24H] and normal late-night salivary cortisol (LNSC). Repeat workup a month later showed serum cortisol of 56ug/dL, ACTH 874 pg/dL, 24-hour UFC of 11880ug/24H and elevated LNSC. Pituitary MRI showed a large heterogenous 3.1 cm partially cystic sellar mass with suprasellar extension. Due to significantly elevated ACTH and short duration of symptoms, we suspected an ectopic source. Due to initial negative testing, except for high ACTH level, a silent corticotroph adenoma was also considered. The patient underwent transsphenoidal resection resulting in significant decrease of cortisol and ACTH postoperatively. Pathology showed a corticotroph adenoma with Ki-67 index of <1%. Case 2: 47-year-old woman with medical history of obesity, polycystic ovary syndrome and a stable 1 cm lung nodule since 2020, presented with fluid retention, worsening acne and resistant hypertension over a 1-year period. She required hospitalization for hypertensive emergency and hypokalemia. Laboratory data showed morning serum cortisol 28 ug/dL, ACTH of 90.1 pg/mL, 24-hour UFC 346 ug/24H, elevated LNSC on two occasions and cortisol 24.3 ug/dl after a 1mg dexamethasone suppression. MRI did not show a pituitary mass. PET dotatate scan revealed a tracer avid 1 cm right upper lobe pulmonary nodule. She underwent a right upper lobe lobectomy, resulting in a significant decrease in cortisol and ACTH levels on postoperative day 1. Pathology confirmed a typical carcinoid tumor. Discussion: High ACTH levels and a short symptom duration often point to ectopic production, paraneoplastic syndromes or corticotroph carcinomas. Cushing's disease typically exhibits mildly elevated ACTH levels, but our cases deviate from this norm, complicating source identification. This atypical presentation highlights the complexity of Cushing's syndrome, challenging conventional diagnostic paradigms. Presentation: 6/1/2024