|Year : 2014 | Volume
| Issue : 4 | Page : 214-216
Type 5 congenital pouch colon: A rare clinical variant
Ajay Verma, Shasanka Shekhar Panda, Minu Bajpai
Department of Pediatric Surgery, All India Institute of Medical Sciences, New Delhi, India
|Date of Web Publication||14-Nov-2014|
Department of Pediatric Surgery, All India Institute of Medical Sciences, New Delhi - 110 029
Source of Support: None, Conflict of Interest: None
Congenital pouch colon (CPC) is a rare variant of anorectal malformation seen predominantly in Indian subcontinent. It has been classified into various forms as per length of colon involved. Type 5 is the rarest form of CPC, which has segmental dilatations and only one case has been reported so far. We present a 1-day-old male child with type 5 CPC with colovesical fistula and management.
Keywords: Anorectal malformation, colovesical fistula, double pouch colon, type 5 congenital pouch colon
|How to cite this article:|
Verma A, Panda SS, Bajpai M. Type 5 congenital pouch colon: A rare clinical variant. J Clin Neonatol 2014;3:214-6
| Introduction|| |
Anorectal malformation (ARM) is a common congenital malformation affecting 2-2.5/10,000 live births worldwide.  Congenital pouch colon (CPC) is a rare clinical variant of ARM comprising 2-9% of total ARM cases. This variant is unique in its preferential occurrence in the northern part of the Indian subcontinent. CPC is rarely reported from the rest of the world.
CPC is also referred as "congenital short colon" in the literature.  The CPC has been classified into five types by Saxena and Mathur.  However, other classifications are also available. ,, Type 5 pouch colon is a very rare variant in which there is segmental dilatation of the colon with intervening normal colon of varying length, the pouch opens into the genitourinary system with a fistula. Although few similar cases have been reported from the Indian subcontinent, this is the only case being reported as type 5 pouch colon. ,
| Case report|| |
A 1-day-old newborn male child, weighing 2600 g, presented to us with the complaints of absent anal opening and progressive abdominal distension. He was the product of nonconsanguinous marriage and delivered by normal vaginal delivery at home with no antenatal care. Postnatal period was uneventful until the parents noticed an absent anal opening, progressive abdominal distension, and meconuria. He was brought to our hospital and worked up as ARM.
The general condition of the child was good, abdominal distension was present, but bowel loops were not visible. There was no history of vomiting. The tip of the penis was stained with meconium indicating fistulous communication to the urinary system. The perineum was flat with poor muscular development. There was no other spinal or musculoskeletal deformity.
Echocardiogram was normal, ultrasonography of the abdomen showed bilateral normal kidneys. X-ray abdomen (anteroposterior erect view) showed dilated left colon with an air fluid level, but the dilated segment was not more than half of the abdomen [Figure 1]a. Invertogram was also done, which showed rectal gas shadow above the pubococcygeal line, indicating high ARM [Figure 1]b.
|Figure 1: (a) X-ray abdomen erect anteroposterior view showing dilated bowel in left hypochondrium (white thick arrow). (b) Invertogram showing high anorectal malformation (gas shadow above pubococcygeal line)|
Click here to view
With a provisional diagnosis of high ARM, we did exploratory laparotomy with left infra-umbilical transverse incision. Intraoperatively, we found two dilated segments of the colon (pouch) with an intervening segment of normal colon (7 cm in length). The ileum was opening into the proximal dilated colonic segment (3 cm diameter), and the distal pouch (5 cm diameter) was opening into the bladder with a wide fistulous opening at the level of the bladder neck [Figure 2]a. The appendix was absent; tinea was absent on the dilated pouch [Figure 2]b. The vascular supply of the colon was from the superior mesenteric vessels. The middle colic and left colic vessels were absent and replaced by an abnormal arborizing vessel supplying the pouch.
|Figure 2: (a) Operative picture showing anatomy of pouch colon type 5, (a) terminal ileum; (b) proximal pouch; (c) intervening normal colon; (d) distal large pouch. (b) Excised distal large pouch, (a) proximal end; (b) distal end opening into bladder|
Click here to view
The colovesical fistula from the distal pouch was divided and repaired with interrupted sutures. The large distal pouch was mobilized and excised; the intervening colonic segment was brought out as end stoma.
Presently patient is 11-month-old and is gaining weight adequately. The child underwent abdominoperineal posterosaggital anorectoplasty (AP-PSARP) with covering ileostomy 1 month back and is awaiting stoma closure. The caliber of the proximal pouch left during the first stage of surgery was found to be that of the normal colon and end colostomy was used for AP-PSARP.
| Discussion|| |
Congenital pouch colon was first described in 1912 by Spriggs in a London Hospital Museum specimen that exhibited absence of the left half of the colon and rectum.  Narsimha Rao et al. in 1984 suggested the name "pouch colon syndrome"  The term "CPC" was first described by Chadha et al.  CPC is classified into five types based on anatomic morphology by Saxena and Mathur.  Type 5 pouch colon is stated as double pouch with short normal interpositioned colon segment and is the rarest of all types.
The embryopathogenesis of type 1 and 2 pouch colon seems to be similar to cloacal exstrophy, arrest of cloacal partition by urorectal septum has been hypothesized for both these conditions. , This early arrest of cloacal septation results in an imperforate anus and appendiceal abnormalities and appears to interfere with the longitudinal growth of the hindgut.  The early septation is also responsible for the high and often wide fistula with the genitourinary tract. The absence of inferior mesenteric vessel and distal colon can be explained by the above fact. The ileum can also be foreshortened along with the presence of Meckel's diverticulum. Despite higher form of ARM associated with type 1 and type 2 CPCs, severe sacral-associated anomalies are rare and the pelvis and perineum are well-developed. The ileocecal valve is absent in type 1 pouch colon and the ileum opens directly in to the colonic pouch.  In type 2 pouch colon, the normal colon extends at least to the level beyond the level of hepatic flexure, but does not extend beyond the level of the descending colon. Both type 3 and type 4 CPCs are associated with a lower level of termination of the pouch colon and the length of the normal colon in both of these types is sufficient for normal function. In both types, especially in type 4 CPCs, the colon is similar to the terminal rectal or rectosigmoid dilatation reported in children with a low type of ARM.  The occurrence of "double pouch" colon or type 5 CPC is extremely rare and documented as a pouch dilatation of the colon caudal to the ileum followed by a 5 cm long segment of normal colon tissue which opened into a second pouch. The type 5 CPC could be explained embryologically based on a vascular lesion theory. In addition to the obliteration of inferior mesentery artery in early fetal life, obliteration of the ileocolic branch of the superior mesenteric artery follows, resulting in the development of the second pouch. The normal interposed colon segment between the pouches is unaffected because the vascular supply through the middle colic branch of the superior mesenteric artery is patent. 
The invertogram or cross table prone X-ray is a necessary adjunct to the initial evaluation; it is used for not only categorizing the ARM as high, intermediate or low malformation, but also provides information about associated vertebral anomaly. The surgical management of pouch colon is challenging, especially type 1 and 2. The preservation of the pouch after coloplasty is required in these cases. In type 3 and 4 the pouch can be excised and remaining colon can be used for pull through procedure. The type 5 pouch colon is unique because the distal pouch is excised and proximal pouch is used for coloplasty, the intervening normal colonic segment can be used for pull through.  The usual approach is staged procedure, but single stage procedures have also been described. 
Anatomically our case is similar to the previously reported case of type 5 CPC. However, our management differs in the point that we excised the distal pouch only and proximal pouch was kept as such with end stoma of intervening normal colon. In previously reported case of type 5 CPC, coloplasty of proximal pouch was done along with excision of distal pouch.  At the time of the second stage surgery in our case, that is, AP-PSARP with covering ileostomy, caliber of the proximal pouch was regressed to that of the normal colon due to diverting end colostomy.
| Conclusion|| |
Congenital pouch colon is a rare clinical variant of ARM and unique in its preferential occurrence in the northern part of the Indian subcontinent. The occurrence of "double pouch" colon or type 5 CPC is extremely rare and documented as a pouch dilatation of the colon caudal to the ileum followed by a 5 cm long segment of normal colon tissue which opened into a second pouch. The usual approach is staged procedure and proximal pouch can be kept as such with diverting end stoma as described in our case.
| References|| |
|1.||Murphy F, Puri P, Hutson JM, Holschneider AM. Incidence and frequency of different types, and classification of anorectal malformations. In: Holschneider AM, Hutson JM, editors. Anorectal Malformations in Children. Berlin, Heidelberg: Springer-Verlag; 2006. p. 163. |
|2.||Singh S, Pathak IC. Short colon associated with imperforate anus. Surgery 1972;71:781-6. |
|3.||Saxena AK, Mathur P. Classification of congenital pouch colon based on anatomic morphology. Int J Colorectal Dis 2008;23:635-9. |
|4.||Gupta DK, Sharma S. Congenital pouch colon. In: Holschneider AM, Hutson JM, editors. Anorectal Malformations in Children. Berlin, Heidelberg: Springer-Verlag; 2006. p. 211. |
|5.||Wakhlu AK, Wakhlu A, Pandey A, Agarwal R, Tandon RK, Kureel SN. Congenital short colon. World J Surg 1996;20:107-14. |
|6.||Narsimha Rao KL, Yadav K, Mitra SK, Pathak IG. Congenital short colon with imperforate anus (CPC syndrome). Ann Pediatr Surg 1984;1:159. |
|7.||Mathur P, Mogra N, Surana SS, Bordia S. Congenital segmental dilatation of the colon with anorectal malformation. J Pediatr Surg 2004;39:e18-20. |
|8.||Chadha R, Gupta S, Tanwar US, Mahajan JK. Congenital pouch colon associated with segmental dilatation of the colon. J Pediatr Surg 2001;36:1593-5. |
|9.||Spriggs NJ. Congenital occlusion of the gastrointestinal tract. Guys Hosp Rep 1912;766:143. |
|10.||Chadha R, Bagga D, Malhotra CJ, Mohta A, Dhar A, Kumar A. The embryology and management of congenital pouch colon associated with anorectal agenesis. J Pediatr Surg 1994;29:439-46. |
|11.||Spencer R. Exstrophia splanchnica (exstrophy of the cloaca). Surgery 1965;57:751-66. |
|12.||Dickinson SJ. Agenesis of the descending colon with imperforate anus. Correlation with modern concepts of the origin of intestinal atresia. Am J Surg 1967;113:279-81. |
|13.||Mathur P, Prabhu K, Jindal D. Unusual presentations of pouch colon. J Pediatr Surg 2002;37:1351-3. |
|14.||Gangopadhyay AN, Shilpa S, Mohan TV, Gopal SC. Single-stage management of all pouch colon (anorectal malformation) in newborns. J Pediatr Surg 2005;40:1151-5. |
[Figure 1], [Figure 2]