6426 Pregnancy-induced ACTH-independent Cushing Syndrome: A Rare Phenomenon Secondary To Aberrant Receptors On Adrenal Glands

Abstract Disclosure: K. Manglani: None. S.T. Sharma: None. Pregnancy-induced hypercortisolism is a rare phenomenon with very few cases reported in the literature. The pathogenesis is thought to be secondary to the expression of aberrant LH/hCG receptors on the adrenal gland that stimulate cortisol production in pregnancy. We present a case of a 31-year-old female with no past comorbidities until her first pregnancy in 2017 when she gained around 50lbs, developed violaceous striae, acne, hirsutism, depression with suicidal ideation for which she was hospitalized twice, and underwent emergent C-section at 34 weeks’ gestation due to pre-eclampsia. She was referred to the Endocrinology clinic post-delivery, and screening for Cushing syndrome was negative at that time: 24-hour urinary free cortisol (UFC), late-night salivary cortisol (LNSC) and 1-mg dexamethasone (dex) suppression test (DST) were normal. She presented again in 2020 during her second pregnancy at 14 weeks gestation, with 20lb weight gain in the first trimester, acne, hirsutism, and easy bruising. Labs showed cortisol of 22.4 mcg/dL (6.2-19.4), ACTH <1.5 pg/mL, total testosterone 168 ng/dL (8-48), androstenedione 751 ng/dL (41-262), DHEAS 91.2 mcg/dL (84.8-378), 24-hour UFC 277 mcg/day (6-42), LNSC 0.671 mcg/dL, 1mg DST with post-dex cortisol 24 mcg/dL (dex level 58 ng/dL), and 8-mg DST with post-dex cortisol level of 28.2 mcg/dL (dex level 457 ng/dL). Testing was consistent with ACTH-independent Cushing syndrome. Ultrasound and MRI of the abdomen/pelvis showed normal adrenal glands with no hyperplasia or mass. Given worsening hypercortisolism and her course during a prior pregnancy, medical treatment with metyrapone was initiated. We started at a dose of 500 mg daily and gradually increased to 1500 mg with close monitoring of her blood pressure and cortisol levels. She underwent vaginal delivery at 38 weeks’ gestation, and the baby required a brief stay in the NICU for respiratory distress but was otherwise doing well. The patient developed secondary adrenal insufficiency post-delivery requiring hydrocortisone, with recovery of her HPA axis in around 10 weeks. Since then, she has been off hydrocortisone with normal UFC, ACTH, and cortisol levels. This case enables discussion regarding the underlying etiology, diagnostic difficulties, and management of this rare condition. Although the exact etiology is unknown, the postulated mechanism is aberrant LH/hCG receptor expression given the patient’s presentation during each pregnancy, normal cortisol levels between both pregnancies, and a brief period of adrenal insufficiency post-delivery. Management of hypercortisolism during pregnancy remains challenging. Metyrapone, a steroidogenesis inhibitor, can be considered for control of hypercortisolemia during pregnancy (off-label) in select cases to prevent maternal and fetal complications. Presentation: 6/1/2024