Year : 2004 | Volume
: 14 | Issue : 2 | Page : 159--160
Antenatal ultrasound appearance of dithoracic paraphagus conjoint twins
A Kharat, A Karamchandani, A Singh, SS Shetty
Department of Radio diagnosis, D.Y. Patil Medical College and Hospital, Deemed University, Pimpri, Pune-18, India
Flat No 2 Building No 34, Ranapur Darshan Society, New Alandi Road, Vishrantwadi, Yerawada, Pune - 411 006
|How to cite this article:|
Kharat A, Karamchandani A, Singh A, Shetty S S. Antenatal ultrasound appearance of dithoracic paraphagus conjoint twins.Indian J Radiol Imaging 2004;14:159-160
|How to cite this URL:|
Kharat A, Karamchandani A, Singh A, Shetty S S. Antenatal ultrasound appearance of dithoracic paraphagus conjoint twins. Indian J Radiol Imaging [serial online] 2004 [cited 2019 Nov 13 ];14:159-160
Available from: http://www.ijri.org/text.asp?2004/14/2/159/28575
A conjoint twin is a rare condition with a reported frequency of 0.1-0.35:10,000 births with hardly any risk of recurrence. Basic pathogenesis being incomplete division of the embryonic disk, which occurs after the 13th day of conception. This condition is due to failure of complete separation of both the fetuses. Most of the conjoined twins are born prematurely, 40% are stillborn, and 35% die within 24 hours. We report one such case of conjoint twins which presented at our institution.
A 25-year-old primigravida presented for routine ultrasound evaluation at 20 weeks. No past history of any medications or possible exposure to teratogenic agents was elicited. Family and personal history were unremarkable.
Ultrasound examination was done with GE Logiq 400 TM ultrasound scanner with 3.5 to 4 MHz convex probe. Ultrasound revealed a twin live, gestation with mild oligohydramnios of 20 weeks gestation. The twins were seen to be fused ventrally at the lower abdomen and pelvis. Twins were seen to share a common urinary bladder which was grossly dilated with early hydronephrosis of fetal kidneys involving both the fetuses. [Figure 1] There was however no evidence of sharing of any other abdominal organs, thorax, head or gastrointestinal tract [Figure 2]. Both twins were in breech presentation. Heads, spines, and extremities of both twins appeared normal. The abdominal walls were fused but otherwise normal, and the external genitalia were male. Umbilical cord was three vessel and normal.
Bowel loops appeared echogenic and dilated this finding along with that of grossly dilated bladder with oligohydramnios raised the possibility of associated anorectal anomaly with bladder outlet obstruction.
Placenta was single, anterior and without any twin separating membrane this suggested monochorionic monoamniotic gestation.
The patient was later on counseled and various options were provided , however the patient opted for termination, the abortus was examined which confirmed the ultrasound findings. [Figure 3] and [Figure 4].
Parapagus - twins that share a conjoined pelvis, one symphysis pubis and one or two sacrums. When the union is limited to the abdomen and pelvis (does not involve the thorax) it is called di thoracic parapagus. If there is one trunk with two heads it is called dicephalic parapagus. If there is a single trunk and a single head with two faces they are di prosopic parapagus.
Congenital anomalies of organs other than the shared ones are present in 50% of the cases of conjoined twins. Cardiac defects are the most common association (20-30% cases). Neural tube defects and midline fusion defects, orofacial clefts, imperforate anus and diaphragmatic hernia are also frequently seen. Polyhydramnios is observed in 50-75% of the cases. Conjoint twins can occur as a part of triplet pregnancy. 
Major role of B mode ultrasound is to study the varying extent of sharing of various organs so that a reasonable assessment of surgical separation can be made .
With extreme degrees of fusion, the twins may be mistaken for a singleton .
Ultrasound can be a cost effective and the prime modality in diagnosis of conjoint twins and further characterization. It provides precise information regarding the nature of anomaly. It allows a complete anatomical work up, target approach scanning for associated lethal malformations. A detailed ultrasound examination to exclude the possibility of conjoined twins is a must in all multiple pregnancies.
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