A wide range of genitourinary pathologies can be diagnosed in utero, from a simple vesicoureteral reflux to a more complex disorder of sexual differentiation. The prognosis and neonatal management of these conditions differ significantly. Evaluation of the fetal perineal anatomy is paramount to making the right diagnosis. The aim of this pictorial essay is to show sonographers how to acquire a perineal midsagittal view in a male fetus, and to demonstrate how this specific view allows assessment of the urethra and penis, to differentiate various genitourinary pathologies.
Keywords: Fetus; Genital anomaly; Megacystis; Penis; Perineal midsagittal view; Posterior urethral valve; Prenatal diagnosis; Ultrasound; Urethra; Vesicoureteral reflux.