Prostatic development and verumontanum in a 46,XX karyotype : An embryological paradox redefining diagnostic algorithm for testicular DSD.

Evaluation of 46,XX Disorders of Sex Development (DSD) with severe virilization often yields inconclusive results. We report a case where alternative diagnostics resolved a significant phenotype-karyotype discordance. A 2-year-old with a 46,XX karyotype and penoscrotal hypospadias was evaluated. Diagnostic urethroscopy revealed definitive prostatic tissue and a verumontanum. These findings provided anatomical evidence of Wolffian differentiation, distinct from Müllerian persistence, and incompatible with Congenital Adrenal Hyperplasia (CAH). Identifying the prostate established the diagnosis of 46,XX Testicular DSD, shifting management from gonadectomy to hypospadias repair. Urethroscopy is indispensable for resolving diagnostic discrepancies missed by standard protocols.