Anal canal duplication in children: a monocentric experience of 12 cases

PURPOSE

Anal canal duplication is a rare malformation characterized by a second perineal opening positioned behind the anus, which is generally observed at 6 o'clock in the lithotomy position. The purpose was to describe six new cases of anal canal duplication (in addition to our previously reported series of six patients) with the aim of providing further clinical information about this anomaly.

METHODS

We described 6 new cases of anal canal duplication in terms of symptoms, anatomical disposition, imaging results, and histopathology. Clinical details of these cases and those already reported (n = 12) were summarized and compared to existing literature.

RESULTS

A total of 12 cases were reported over 34 years. 17% of the patients were male, constituting the only subgroup to present a communication with the digestive tract. A single patient, diagnosed at 12 years, was symptomatic. Half of the patients had at least one associated malformation. All patients underwent surgery, either with a posterior sagittal or perineal approach.

CONCLUSION

Diagnosis of anal canal duplication should be suspected when a perineal opening positioned behind the anus is present, and necessitates further exploration by a comprehensive clinical examination and imaging. Surgery is always required, typically performed via a posterior sagittal approach. The postoperative course is usually uncomplicated.

The Controversy of Surgical Intervention for Anal Canal Duplication in Children

Objective:

Since the first definition of anal canal little has been discovered about the etiology of this rare condition. We present four asymptomatic cases of anal canal duplication with diverse clinical and surgical findings.

Methods:

A retrospective chart review was performed on four infants presenting with asymptomatic anal canal duplication, born between 2014 and 2016. Clinical characteristics and pathologic findings of patients either by radiological imaging or pathology were evaluated. The primary outcome measure was the complications.

Results:

All patients were followed-up with physical examination and ultrasound for a mean of 3.5±1.0 years, lastly seen at the beginning of 2018. The female to male ratio was 3:1. Duplicate anal canal length varied between 12-20mm, and two of the four patients had a presacral cystic mass confirmed as a tail gut cyst following surgery. At follow-up, none of the patients had developed symptoms related to anal canal duplication, regardless of whether they had surgical intervention.

Conclusion:

Though surgical management is the preferred treatment for anal canal duplication, it seems that patients who do not undergo surgery might remain free of symptoms, suggesting that surgical intervention may be unnecessary.

Anal canal duplication and triplication: a rare entity with different presentations

Anal canal duplication (ACD) is the rarest of gastrointestinal duplications. Few cases have been reported. Most cases present as an opening in the midline, posterior to the normal anus. The aim of our revision is to contribute with eight new cases, some of them with unusual presentations: five presented as the typical form, one with a perianal nodule, and two presented as two separate orifices (anal canal triplication). Complete excision was performed in all patients with no complications. ACD is the most distal and the least frequent digestive duplication. Its treatment should be surgical excision, to avoid complications such as abscess, fistulization, or malignization. Anal canal triplication has never been described before.

Fetal growth of the anal sinus and sphincters, especially in relation to anal anomalies

PURPOSE AND METHODS

The anal sinuses, small furrows above the pectinate line, sometimes form perianal abscesses in adults. We examined the pattern of fetal growth of the anal sinus and sphincters using 22 mid-term (8-18 weeks) and 6 late-stage (30-38 weeks) fetuses.

RESULTS

In mid-term fetuses, the external and internal sphincters gradually increased in thickness, depending on specimen size (from 0.2 to 1.5 mm), whereas the anteroposterior diameter of the anal canal at the epithelial junction was relatively stable (0.5-1.0 mm) irrespective of specimen size. Anal canal diameter increased less than twofold between mid-term and late-stage fetuses, from 0.5-1.0 to almost 2 mm, whereas sphincter thickness increased over tenfold, from 0.2-1.5 to almost 3.5 mm. The anal sinus often showed balloon-like enlargement when the sphincter muscle bundles were tightly packed in mid-term, but not in late-stage fetuses.

CONCLUSIONS

Large concentric mechanical stress from the sphincters in late-stage fetuses apparently prevented the anal sinus from expanding in a balloon-like manner. Conversely, to avoid anal stenosis, the growing sinuses maintained a luminal space of the anal canal in response to stress from rapidly growing sphincters. The inferiorly extending sinus usually provided temporal double canals separated by a thick column. In the presence of double lumens, anal canal duplication is likely to develop without any abnormalities of the anal epithelium and sphincters.

Late presentation of anal canal duplication in adults: a series of four rare cases

Anal canal duplication (ACD) is a very rare condition, especially in adults. Four cases in adults are reported. In three cases, the orifice of duplication was located behind the native anus, and in one case, it was located anteriorly. In all cases, no communication between the anal canal and the tract of duplication was noted. Complete removals of the duplications were done through a perineal approach. Histology showed fibro-muscular tissue lined with a squamous epithelium. The postoperative courses were uneventful.