Prolonged Adrenal Insufficiency After Failed Cryoablation and Osilodrostat for Cushing Syndrome in Nodular Adrenal Disease

Nodular adrenocortical disease is an entity more commonly recognized in recent years. We present a case of bilateral adrenal nodular disease in a young woman with ACTH-independent Cushing syndrome. She was treated with medical therapies at her preference to avoid adrenal insufficiency (AI) from surgery. She developed intolerance to medical therapy. Cryoablation of the right adrenal nodule was performed after adrenal vein sampling identified the right adrenal as the dominant source of cortisol. Cortisol levels were normal while on medical therapy after cryoablation but quickly became elevated after discontinuing medical therapy. The patient was then treated with osilodrostat and ultimately developed medication-induced AI that has persisted for more than 3 years. Due to the increased availability of new medications to treat Cushing syndrome, we present our experience to educate endocrinology audiences about the unexpected responses to medications. Using osilodrostat (off-label) in this patient led to prolonged primary AI after 4 months of use and now presumed permanent AI 36 months after discontinuation of treatment.