Incidental discovery of neglected 11β-hydroxylase deficiency causing 46,XX disorder of sex development in a 35-year-old adult: A radiologically driven diagnosis.

11β-hydroxylase deficiency (11β-OHD) is the second most common form of congenital adrenal hyperplasia (CAH), characterized by androgen excess, mineralocorticoid-driven hypertension, and hypokalemia. We report a 35-year-old individual with a 46,XX karyotype, registered and raised male since birth, in whom a disorder of sexual development (DSD) had remained unrecognized. Abdominal MRI performed for nonspecific abdominal pain revealed bilateral giant adrenal myelolipomas on macronodular adrenal hyperplasia and a retro-vesical uterus-like structure. On examination, external genitalia showed complete masculinization (Prader stage 5); dedicated pelvic MRI further demonstrated a markedly enlarged uterus with diffuse adenomyosis, in a patient who had never menstruated. Hormonal findings were consistent with classical 11β-OHD (DOC ∼140× the upper limit of normal, ACTH 12× normal, elevated adrenal androgens, suppressed gonadotropins, and absent AMH); CYP11B1 genetic testing, which would provide molecular confirmation, was not available. Glucocorticoid replacement normalized potassium and improved blood pressure, with ongoing multidisciplinary follow-up. This case highlights the radiological phenotype of neglected CAH in adulthood and the role of imaging in characterizing complex DSD when clinical signs alone are insufficient to reach a diagnostic conclusion.