Prenatal diagnosis of non-janiceps type of cephalopagus conjoined twins: a case report

BackgroundConjoined twin pregnancy is a very rare variety of twin pregnancy which results from the failure of complete separation of a zygote after 13 days, 'cephalopagus' being the rarest variety of such twin pregnancies. Two forms of cephalopagus conjoined twins have been described in the literature: Janiceps (two faces are on the either side of the head) and non-janiceps (with one head and a single face); non-janiceps type being even rarer. The features that may hint towards the diagnosis on ultrasound include inseparable fetal bodies, unvarying relative positioning of the two fetuses, both heads persistently at the same level to each other, bi-breech or bicephalic presentations and a single umbilical cord with more than three vessels. 3-D ultrasound and Fetal MRI may help in confirmation of this rare entity.Case presentationA 19-year-old primigravida, presented at 12 weeks of gestation for antenatal ultrasound. Ultrasonography showed evidence of a conjoined twin with a single head and single face, fused thoracic cavities with single heart, two lungs, fused upper abdomen with shared stomach and liver, separate pelvic cavities with two different urinary bladders and two pairs of upper and lower limbs. Fetal MRI corroborated these findings. The pregnancy was terminated vaginally, and cephalopagus fetus was delivered. The parents were appropriately counselled for future pregnancies.ConclusionsA very rare case of non-Janiceps variety of cephalopagus conjoined twin gestation which was detected at 12 weeks of gestation by antenatal ultrasound and confirmed on fetal MRI. Early antenatal diagnosis is extremely important for appropriate and timely management as the prognosis is very poor in such twins. Antenatal ultrasound and fetal MRI prove very beneficial in this aspect as well as for diagnosis of other associated fetal abnormalities.