Adrenal Cushing’s Syndrome Treated With Preoperative Osilodrostat and Adrenalectomy

BACKGROUND/OBJECTIVE: Reducing severity of Cushing’s syndrome caused by an adrenal adenoma (adrenal Cushing’s syndrome [ACS]) might decrease morbidity and mortality risk in adrenalectomy. We used off-label osilodrostat, approved in the United States for pituitary Cushing’s disease, to reduce cortisol levels and disease severity before adrenalectomy 3 weeks later. CASE REPORT: A 48-year-old woman with a 6-year history of obesity, depression, and anxiety and 3-year history of diabetes and hypertension was admitted with vomiting and lumbar back pain. Facial plethora and hirsutism, posterior cervicothoracic fat pad, and truncal obesity coupled with morning serum cortisol >13 μg/dL after 1 mg oral dexamethasone suppression, urinary free cortisol 1324 μg/24hr (4.0-50.0 μg/24 h), and adrenocorticotropin <5 pg/mL (6-50 pg/mL) confirmed ACS. Computed tomography with contrast revealed a 3.4-cm right adrenal mass. Osilodrostat 2 mg twice daily initiated at discharge was increased to 4 mg twice daily on day 6. Three days later, she reported nausea, vomiting, and fatigue. Despite 7.2 μg/dL morning cortisol, adrenal insufficiency was suspected; osilodrostat was reduced to 2 mg twice daily and maintenance oral hydrocortisone 20 mg daily was added with symptom resolution. Prior to adrenalectomy, morning cortisol was 5.1 μg/dL, fasting glucose was 122 mg/dL, and she self-discontinued diabetes medications. Hypertension remained unchanged (149/100 vs 151/94 mmHg). Adrenalectomy revealed a 3.4-cm focally pigmented adrenocortical adenoma. DISCUSSION: Three-week treatment of overt ACS with off-label osilodrostat reduced cortisol and glucose levels before curative adrenalectomy. Abrupt cortisol reduction led to suspected adrenal insufficiency managed with maintenance hydrocortisone. CONCLUSION: Osilodrostat might help reduce ACS severity before adrenalectomy. Adrenal insufficiency is a risk but can be safely managed with hydrocortisone.