Razi Journal of Medical Sciences

Pilonidal sinus or sacrococcygeal fistula is a cyst or abscess near or on the natal cleft of the buttocks that often contains hair and skin debris. The sinus track goes in a vertical direction between the buttocks. Rarely, a pilonidal sinus occurs in other sites of the body.

The exact cause is not clear. This report describes a 31-year-old man with pilonidal sinus who was complaining of pain, pus-like and blood-tinged discharge in perianal region. The patient was admitted with a primary diagnosis of anal fistula at 5 o'clock in the “lithotomy position” and 2 cm from anal verge combined with cyst at 3 cm of the anal fistula. In anal inspection and rectal examination, the external orifice of the fistula with a 20 -30 mm induration and pus-like discharge were observed. Explore the fistula using a fistula probe was unsuccessful. The cyst was removed and its pathologic result showed pilonidal sinus.