Prenatal diagnosis of sirenomelia with anencephaly and craniorachischisis totalis A case report study

Rationale: Sirenomelia and anencephaly are well-defined congenital malformations that usually occur independently. Patient concerns: We report a case of combined sirenomelia, anencephaly and complete rachischisis, diagnosed in the 16th week of gestation. Diagnoses: To our knowledge, this is the 7th case in the literature and the first that is diagnosed so early in pregnancy. Interventions: The final diagnosis is confirmed with radiological examination after the termination of pregnancy. Outcomes: Prenatal diagnosis of sirenomelia is difficult due to the presence of kidney agenesis and severe oligohydramnios. Lessons: The combination of sirenomelia and craniorachischisis totalis is extremely rare and prenatal ultrasound scan are a challenge, even for experts in the field.