Currarino syndrome – An infrequent cause of intractable constipation

A 18-month-old girl child presented with complaints of chronic constipation and abdominal distension since birth with increasing abdominal distension for 3 months. She was born through normal vaginal delivery and there was no developmental delay. On clinical examination, there was abdominal distension. External genitalia appeared normal.

Screening ultrasound was performed which showed a highly gaseous abdomen and did not add on much into information. CT topogram showed a crescent-shaped defect in the right side of the sacrum involving S2 –S5 vertebrae and coccyx. A homogeneous soft tissue radiopacity was seen in the pelvic cavity. Large bowel loops were prominent. On abdominal contrast-enhanced CT scan, there was smooth circumferential wall thickening of anal canal and anorectal junction, for the length of 35 mm approximately with maximum wall thickness of 10 mm. Upstream large bowel loops were dilated with maximum luminal calibre of 36 mm and demonstrated small bowel faeces sign. A large well defined presacral cystic lesion, measuring approximately 53x50x43 mm was seen communicating with the spinal canal through the sacral bony defect of size 4.2mm. Mild peripheral enhancement was seen on post-contrast images. No internal calcific foci, air or fat component were present within the lesion. No obvious neural component was present in the hernial sac. Urinary bladder was compressed and displaced anteriorly by the grossly dilated rectum with compression of bilateral vesicouretric junction and upstream hydroureteronephrosis. The right kidney showed few small areas of reduced enhancement suggesting the possibility of pyelonephritis.

The patient underwent laprotomy at a private centre. Discharge summary was reviewed. Excision of presacral cystic mass was performed which was consistent with anterior meningocele. Anoplasty was performed for anal canal stenosis. Postoperative period was uneventful.

Background

Currarino syndrome is a rare congenital disorder characterised by a triad of anorectal malformation, sacral bony abnormalities and presacral mass [1] . In 50% cases, its pattern of inheritance is autosomal dominant and is associated with mutation in the MNX1 gene located on chromosome 7q36 [2,3]. Incidence is 1-9 cases per 100000 population[4]. Triad of this syndrome was first recognized by Kennedy in 1926, but it was Guido Currarino in 1981, who defined these disorders as a syndrome on the basis of common embryogenesis.

Clinical Perspective

Clinical presentation is variable ranging from asymptomatic cases to severe constipation and other fatal complications. Patients can present with complete triad of sacral bony defect, presacral mass and anorectal malformations or present with incomplete triad in which one or two components are missing [5,6].

Imaging Spectrum

On Imaging, plain radiograph is very useful in detection of sacral bony defect. The most common abnormality consists of unilateral crescent-shaped defect in vertebral bodies involving S2-S5 vertebrae, commonly known as scimitar sacrum or Os Sacrum [7,8]. First sacral vertebra is always preserved [1]. Other radiological features are presacral mass and anorectal malformations. Presacral mass includes anterior meningocele, immature teratoma, hamartoma, neuroblastoma, epidermoid & dermoid cyst, or lipoma amongst which most common is anterior meningocele, which was also seen in our case [9,10]. Anal atresia, anal stenosis, imperforate anus and cloacal anomalies are commonly seen anorectal malformations. Urological anomalies associated with this syndrome include congenital single kidney, vesicoureteric reflux, hydroureteronephrosis, voiding dysfunction, urinary incontinence, duplex ureters [4]. CT  helps to find out the cause of constipation as well as in diagnosis of presacral masses and associated complications due to pressure effects. MRI in  addition  may demonstrate  neurological complications like occult spinal dysraphism and other spinal cord anomalies including syrinx, low lying conus, diastematomyelia, spinal lipoma, and tethered cord [11].

 Outcome

Treatment protocol depends on type of presentation. Surgical management is recommended in all cases including excision of presacral mass and correction of anorectal malformation [12].

Take-Home Message

Currarino syndrome being a rare disorder, is difficult to diagnose because of its variable presentation, which ranges from asymptomatic to severe constipation and other neurological symptoms. Sometimes it is very challenging for clinicians to diagnose it in absence of visible anorectal malformations, therefore Radiologists have a major role in diagnosis of such rare disorders. Plain radiographs are very helpful in providing clues to diagnosis.                                        

Written informed patient consent for publication has been obtained.