An unusual cause of perianal fistula

Abstract

Anal pain is a common presentation in colorectal clinic. Accurate diagnosis often requires examination under anaesthesia as pain prevents careful assessment. This report intends to highlight a rare cause of a superficial perianal fistula caused by an ingested foreign body. A 36-year-old Afro-Caribbean gentleman underwent examination under anaesthesia of rectum. He had a 2-week history of perianal pain and discharge. Intra-operatively, a piece of bone from a pork spare rib was found embedded within the superficial subcutaneous fistula. There was an associated abscess cavity adjacent to the fistula, which was curetted. The fistula was laid open and the bone was removed. The cavity was successfully left to heal by secondary intention. Ingested foreign body is a very unusual cause of perianal sepsis and subsequent fistula formation. Incision and drainage of the abscess along with removal of foreign body is the key to immediate pain relief and cure.

Figure 1

Subcutaneous perianal fistula containing fragment of pig bone

Figure 2

Fragment of pig bone