Sirenomelia. Angiographic demonstration of vascular anomalies.

A 1,730-g infant with severe caudal regression syndrome (sirenomelia) died shortly after delivery, after a 34-week gestation. Autopsy findings included multiple skeletal anomalies, renal agenesis, amnion nodosum, and a single lower extremity. Postmortem arteriography demonstrated a persistent vitelline artery and documented the vascular pattern within the lower extremity. To our knowledge, angiographic demonstration of the lower limb vascularity has not been described previously in sirenomelia. The angiographic findings support the pathogenetic concept of limb bud fusion and malrotation of the limb in sirenomelia after damage to the posterior axis mesoderm in early embryonic life. Postmortem arteriography is an inexpensive, retrievable, and easy means of documenting vascular anomalies in the fetus or infant with multiple congenital abnormalities.