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Perianal fistula

Case contributed by Fakhry Mahmoud Ebouda
Diagnosis certain

Presentation

Perianal pain and discharge for two years.

Patient Data

Age: 25 years
Gender: Male
mri

A relatively thick-walled fistulous track traverses both internal and external anal sphincters piercing and penetrating through the left ischioanal fossa. Its internal opening pierces the anal canal anteriorly near 1 o’clock where a fairly defined restricted collection / abscess formation is seen. The collection measures 1.8 x 1.5 cm. It shows restricted diffusion. Then the thick track protrudes and proceeds to make a hook down anteriorly along the ischioanal fossa for a length of about 9.7 cm. Its external opening being near 3 o'clock. The track has a thick enhanced wall and high signal intensity enhanced content.  

Case Discussion

The description of this fistula is matching with a trans-sphincteric type that represents 25% of perianal fistula. The track of the fistula crosses from the intersphincteric space, through the external sphincter, and then passes into the ischiorectal fossa. It is complicated by abscess formation, resulting in a classification of grade 4 trans-sphincteric fistula.

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