Prenatal Diagnosis of Partial Androgen Insensitivity Syndrome by Means of a 4-D Ultrasound Technique

Abstract

J Obstet Gynaecol Can 2012;34(1):9 A 27-year-old primigravid woman was referred to our institution at 26 weeks’ gestation with suspected fetal ambiguous genitalia. Detailed real-time grey-scale and 4-D ultrasound examination of the fetal genitalia showed a micropenis with one testicle located in the relatively small scrotum (Figure 1; arrow indicates testicle). A diagnosis of X-linked partial androgen insensitivity was proposed after ultrasound features were compiled and a pedigree analysis performed. The patient delivered a 3100 g baby by Caesarean section at 39 weeks’ gestation. Findings from the physical examination of the newborn were completely normal except for genital ambiguity. The phallic structure was 1 cm long and 0.5 cm wide, with a single urogenital opening at the base of the phallic shaft and bilateral palpable gonads in the bifid scrotum (Figure 2). Visualization of the fetal testicle in the scrotum by ultrasonography is important in the prenatal diagnosis of partial androgen insensitivity.1