Transposition of the external genitalia associated with caudal regression

Complete transposition of the external genitalia is a rare abnormality that occasionally is associated with the caudal regression syndrome. We report the pathological findings of this abnormality in a male stillborn and a female newborn. The male stillborn had extensive urogenital anomalies as well as complete transposition of the external genitalia and agenesis of the lumbar spine. The female patient had renal tract anomalies and ambiguous external genitalia with a phallic structure in the gluteal cleft. In surviving infants with transposition of the external genitalia immediate evaluation of the urogenital system is necessary to identify the full extent of any associated internal defects.