A Rare Cause of Chronic Constipation

Question: An otherwise healthy 7-year-old boy presented to the gastroenterology clinic with a history of longstanding constipation and encopresis. The past medical history was significant for an intermediate level anal bar causing an imperforate anus, requiring a minor anoplasty in the neonatal period. The family and pregnancy history were noncontributory. A stool mass could be palpated on abdominal physical examination and an abdominal radiograph identified a moderate amount of stool in the colon and absence of the right lower sacrum resulting in a “sickle”-shaped sacrum (Figure A). This was confirmed by magnetic resonance imaging (MRI), which also revealed a small, heterogeneous, presacral mass (Figure B). What is the diagnosis? Look on page 1091 for the answer and see the Gastroenterology web site (www.gastrojournal.org) for more information on submitting your favorite image to Clinical Challenges and Images in GI. The classical phenotypic triad of Currarino syndrome (CS) includes a presacral mass, anorectal malformation, and partial sacral dysgenesis. The most common presentation of CS is early, chronic constipation. Interestingly, the constipation is not due to physical obstruction but to a poorly understood intestinal pseudo-obstruction. No defects in either the innervation or the musculature of the hindgut have been identified.1Crétolle C. Zérah M. Jaubert F. et al.New clinical and therapeutic perspectives in Currarino syndrome (study of 29 cases).J Pediatr Surg. 2006; 41: 126-131Abstract Full Text Full Text PDF PubMed Scopus (60) Google Scholar The form of sacral dysgenesis is unique to CS. The first sacral vertebra is preserved and forms the pathognomonic scimitar or sickle shape with the remnant of S2-S5. The pre-sacral mass is generally cystic and has the same intensity as cerebrospinal fluid on MRI.2Duru S. Karabagli H. Turkoglu E. et al.Currarino syndrome: report of five consecutive patients.Childs Nerv Syst. 2014; 30: 547-552Crossref PubMed Scopus (9) Google Scholar The mass has been identified as an anterior myelomeningocele in 60%, a teratoma in 25%, and a dermoid or other tumor in 15% of cases.3Köchling J. Pistor G. Märzhäuser Brands S. et al.The Currarino syndrome–hereditary transmitted syndrome of anorectal, sacral and presacral anomalies. Case report and review of the literature.Eur J Pediatr Surg. 1996; 6: 114-119Crossref PubMed Scopus (71) Google Scholar Malignant degeneration of the presacral mass has been described in many cases of CS and has occurred in patients as young as 2 years old.2Duru S. Karabagli H. Turkoglu E. et al.Currarino syndrome: report of five consecutive patients.Childs Nerv Syst. 2014; 30: 547-552Crossref PubMed Scopus (9) Google Scholar The anal malformation is most frequently anorectal stenosis or imperforate anus, as seen in our patient.2Duru S. Karabagli H. Turkoglu E. et al.Currarino syndrome: report of five consecutive patients.Childs Nerv Syst. 2014; 30: 547-552Crossref PubMed Scopus (9) Google Scholar In addition to the three main features, CS is also associated with Mullerian duplication, tethered spinal cord, and neural tube defect.2Duru S. Karabagli H. Turkoglu E. et al.Currarino syndrome: report of five consecutive patients.Childs Nerv Syst. 2014; 30: 547-552Crossref PubMed Scopus (9) Google Scholar The presentation of the complete CS triad is quite rare; fewer than one-half of those with CS demonstrate the triad and it has been described in the literature in <250 patients.3Köchling J. Pistor G. Märzhäuser Brands S. et al.The Currarino syndrome–hereditary transmitted syndrome of anorectal, sacral and presacral anomalies. Case report and review of the literature.Eur J Pediatr Surg. 1996; 6: 114-119Crossref PubMed Scopus (71) Google Scholar The actual incidence of CS is unknown; however, it is likely underdiagnosed because the phenotype is expressed variably and may go unrecognized in the absence of radiologic assessment. CS may be subdivided into a sporadic and an autosomal-dominant, familial form. In the absence of family history of similar problems in our patient’s case, we did not perform any genetic testing. Current opinions on the management of CS support serial MRI assessment of the sacral mass, especially throughout childhood, to monitor for malignant transformation.2Duru S. Karabagli H. Turkoglu E. et al.Currarino syndrome: report of five consecutive patients.Childs Nerv Syst. 2014; 30: 547-552Crossref PubMed Scopus (9) Google Scholar Surgical intervention is the mainstay of treatment for imperforate anus and rectal stenosis if symptomatic. However, there exists no consensus regarding the surgical intervention of asymptomatic patients.2Duru S. Karabagli H. Turkoglu E. et al.Currarino syndrome: report of five consecutive patients.Childs Nerv Syst. 2014; 30: 547-552Crossref PubMed Scopus (9) Google Scholar