Prenatal Sonographic Image of Sirenomelia with Anencephaly and Craniorachischisis Totalis

Abstract

Sirenomelia is a rare congenital malformation characterized by varying degrees of fusion of the lower extremities. It is commonly associated with severe urogenital and gastrointestinal malformations; however, the association of sirenomelia with anencephaly and rachischisis totalis is extremely rare. To our knowledge, the prenatal sonographic images of this association have not been previously published. Here, we present prenatal sonographic images of this association, detected during the 17th week of gestation through combined two-dimensional, four-dimensional, and color Doppler ultrasound. Two-dimensional ultrasound images showed anencephaly, spina bifida, and possible fusion of the lower limbs. Three-dimensional HDlive rendering images confirmed the final diagnosis of sirenomelia with anencephaly and rachischisis totalis. The patient opted to undergo medical termination of pregnancy and delivered a fetus with fused lower limbs, anencephaly, and rachischisis totalis confirming the in utero imaging findings. Awareness of these rare associations will help avoid misdiagnoses and facilitate prenatal counselling. This case highlights the importance of a thorough ultrasound examination.

Prenatal diagnosis of craniorachischisis totalis

“…Since that time, other authors have described it as well 15 16. The association between sirenomelia with craniorachischisis totalis has also been described, but it is extremely rare with only nine cases reported in the literature to date 17–20…”

Sirenomelia associated with an anterior abdominal wall defect: a case report

“…Although the genetic predisposition has been raised, etiology of sirenomelia remains unclear. There is no report on instances of familial recurrence of sirenomelia [12, 13]. The results of karyotype testing done on sirenomelia cases reported in the literature are almost all normal.…”