A complex fistula-in-ano presenting as a soft tissue tumor

Anorectal abscess and fistula are quite commonly encountered diseases. Both of these are the acute and chronic manifestations of the same entity. While abscess are thought to begin as an infection in the anal glands, their spreading into adjacent spaces results in a fistula formation. At many times this spread occurs in a complex pattern which is difficult to map and treat.

This paper describes a complex perianal fistula that presented as a painless benign lump in the upper outer quadrant of the right buttock. The lump initially thought to be a soft tissue swelling was later diagnosed to be a chronic abscess cavity extending medially toward the anal canal in the form of a complex fistulous tract.

Complex perianal fistulas are difficult to treat and are prone to recurrences. Correct diagnosis and characterization of the fistula is essential to optimize the treatment. Clinical examination alone may not give a correct picture of the actual disease, thereby requiring radiological investigations like MRI.

Although rare, sometimes common clinical conditions like fistula-in-ano may also present in complex manner. It is important to establish the diagnosis firmly and map the fistula properly before going in for surgery. Complexity of fistulas and improper mapping often leads to recurrences and other complications like incontinence.