Mixed gonadal dysgenesis with an ovotestis on imaging mimicking ovotesticular disorder of sexual differentiation.

Mixed gonadal dysgenesis (MGD) is a rare disorder of sexual development. Also known as 45XO/46XY mosaicism, MGD is characterized by highly variable sexual phenotypes and an increased risk of gonadal malignancy. Patients with MGD often have a unilateral descended gonad and contralaterally either a streak gonad or no gonad. We present the case of a patient with a dysgenetic, nonpalpable gonad with imaging features of an ovotestis. These imaging features are generally more indicative of ovotesticular disorder of sexual development (previously true hermaphrodite), which is a condition with low risk of gonadal malignancy. Further evaluation with histology and genetic analysis confirmed the diagnosis of MGD. It is important to diagnose MGD to allow for early operative intervention and screening for malignancy.