Congenital disorders of sexual differentiation: MR findings.

A broad spectrum of anomalies of sexual differentiation may exist at birth. These include male and female pseudohermaphroditism, gonadal dysgenesis, and true hermaphroditism. When ambiguous genitalia are present, expedient identification of the anomaly is required for proper gender assignment and appropriate surgical or hormonal correction. As the appearance of the external genitalia often is not distinctive enough to make a specific diagnosis, this must be accomplished by clinical findings along with a combination of cytogenetic, biochemical, and radiologic studies. Because the causes of abnormal sexual differentiation are diverse and often exhibit incomplete expression, they produce much anatomic variability. Sonographic and radiographic studies are often used initially to evaluate such conditions. The noninvasive multiplanar nature of MR imaging makes it a useful alternative method with which to characterize the abnormal anatomy in this group of disorders, as we illustrate in this pictorial essay.