This article presents a rare case of cloacal dysgenesis sequence (CDS) detected at 23 weeks of gestation in a 36-year-old woman's first ongoing pregnancy. The fetal ultrasound demonstrated anhydramnios, megacystis, the "keyhole sign" and empty bilateral renal fossae, findings consistent with the fetal obstructive uropathy (FOU). A subsequent postmortem carried out confirmed a diagnosis of a cloacal dysgenesis sequence, characterized by the absence of anal, genital and urinary openings with intact perineum covered by smooth skin and a phallus-like structure.
Keywords: cloacal dysgenesis sequence; fetal obstructive uropathy; keyhole sign.