Sirenomelia; A Case Report and Review Article

Objective: Sirenomelia or Mermaid syndrome is characterized by complete or incomplete fusion of lower extremities with an incidence of 1.5 to 4.2 in 100000 live births. It occurs in gastrulation period (beginning of third gestational week) because of insufficient mesoderm formation in caudal region. Various theories have been postulated to explain the etiology of sirenomelia such as pressure theory which denotes that some intra-uterine force, probably amniotic, acts on the tail of embryo. The aim of this study was to present a rare congenital malformation. In addition we reviewed the pertinent literature in this regard.
Case Presentation: We report a case of sirenomelia with multiple interesting anomalies including bilateral renal agenesis, absent external genitalia, gall bladder agenesis, colorectal agenesis from mid ascending colon, ileosacral dysgenesis, meningocele, caudal tapering of abdominal aorta and single umbilical artery. History, detailed autopsy findings and review of literature are presented in this report.
Conclusion: Sirenomelia is a rare congenital malformation leading to stillbirth or early death after birth due to multiple anomalies, so prompt intra-uterine diagnosis and therapeutic abortion is of utmost importance.