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2019-10-28  Case of the week # 510  © Fabien Ho

Answer of the case of the week # 510
December 5 - January 2
Dr Ho F.1, Dr Cuillier F.2, Dr J-L Michel3

1. Radiologist, private sector, 97400 Saint-Denis, Reunion Island, France. 
2. Department of Obstetrics, Felix Guyon Hospital, Reunion Island, France.
3. Department of Paediatric surgery, Felix Guyon Hospital, 97400 Saint-Denis, Reunion Island, France. 

Case report
This patient had been referred to our hospital after 1st trimester screening for an unsual image. Previous personal, familial and obstetrical history is non relevant.
Our US examination at 13WG revealed the following anomalies:

Image 1 and video 1: nonspecific cystic image below the stomach and to the left of the bladder. This image then disappeared upon follow-up, including 2nd trimester US exams.

Upon follow-up, this image disappeared and was nowhere to be seen on 2nd trimester scan.
At the 3rd trimester scan, we noted the following aspect in the pelvis of the female fetus:??

Image 2 and video 2: Unfortunately, our US scans displayed poor definition due to patient's overweight (over 110 kilograms). Macrocystic image in the pelvis of a female fetus, with internal echoic deposits. Ovarian cyst? Unusual septum within the image: due to blood clot? We quickly performed an MRI as soon as possible because we had numerous possible differentials in mind.

Therefore we did perform an MRI at 35 weeks of pregnancy:

Images 3-20the macrocystic image was located in the midline and extended way down into the pelvis towards the perineal area. It displayed an incomplete midline septum. Hypointense deposits are seen within. Its shape and location on the midline, behind the bladder are very suggestive of an hydrometrocolpos with a partial uterine septum.
The bladder was best seen on sagittal and axial view. It was pushed to the front by what appears to be an hydrometrocolpos, and was less than half-full. In contrast, there was dilation of both ureters and both kidney pelvis above the hydrometrocolpos. Either there was a mass effect on both ureters, either there was a low-urinary-tract-obstruction (LUTO) with "valve-effect" towards the colpos.
The meconium has a remarkable T1 hyperintense physiological signal, which is very handy to follow the large bowel. On axial, sagittal, and coronal view, no hyperintense T1 meconium was seen in the pelvis. The large bowel likely ended 4 centimeters above the perineal skin: most likely a high-type anorectal malformation. There was no bowel dilation nor enterolithiasis. Spine and spinal cord showed normal MRI appearance.

Images 3-5, Axial T1

Images 6-8, Axial T2 

Images 9-11, Coronal T1

Images 12-14, Coronal T2 

Images 15-17, Sagital T1 

Images 18-20, Sagital T2 

This case is very similar to one of our previous cases here 
-oddly there was an atypical cystic pelvic image on first trimester US, which was non specific. Some may believe it does represent a communication between the bladder and the bowel (Prof. R. Chaoui).
-maternal overweight really limited US examination, thus the anal muscle hypoechoic ring could not be assessed. 
-there was no fetal ascites.
-the uterine septum was partial.

The combination of an hydrometrocolpos, an anorectal malformation and bilateral ureter & kidney pelvis dilation was very suggestive of a persistent cloaca.
The diagnosis was confirmed at birth: distended abdomen and pelvis with an imperforate anus were seen. Upon surgery, the large bowel was connected to the uterus through a cloacal channel. Anatomic repair is hardly doable in the neonatal period. Therefore, colostomy was performed, and drains were put in both bladder and uterus.For more information about cloaca, refer to the references below.


1.Gupta A, Bischoff A, Peña A, Runck LA, Guasch G. The great divide: septation and malformation of the cloaca, and its implications for surgeons. (2014) Pediatric surgery international. 30 (11): 1089-95. doi:10.1007/s00383-014-3593-8 - Pubmed
Bischoff A, Calvo-Garcia MA, Baregamian N, Levitt MA, Lim FY, Hall J, Peña A. Prenatal counseling for cloaca and cloacal exstrophy-challenges faced by pediatric surgeons. (2012) Pediatric surgery international. 28 (8): 781-8. doi:10.1007/s00383-012-3133-3 - Pubmed

2.Alfred Z. Abuhamad, Rabih Chaoui. First Trimester Ultrasound Diagnosis of Fetal Abnormalities. (2017) ISBN: 9781451193725
Fayard C, Blondiaux E, Grigorescu R, Garel C. AIRP best cases in radiologic-pathologic correlation: prenatal and postmortem imaging of a complex cloacal malformation. (2014) Radiographics : a review publication of the Radiological Society of North America, Inc. 34 (7): 2056-63. doi:10.1148/rg.347140018 - Pubmed numerous articles and case showing multiples situations, slightly different on from another, leading to persistent cloaca diagnosis:

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