Unusual sonographic finding in a patient with late recurrence of a perianal fistula

We describe a case of late recurrence of a perianal fistula in a 51‐year‐old man with a 4.5‐year history of recurrent perianal fistulas and abscesses. This was the fourth recurrence he had experienced; at each occurrence, he had undergone various examinations, including sigmoidoscopy, anoscopy, barium enema, fistulography, probe exploration, instillation of hydrogen peroxide, and/or sonography, and he had also undergone surgery. At our examination, transperineal sonography with a portable ultrasound scanner revealed an echogenic linear structure within the fistulous tract. Under endoanal sonographic guidance, surgery was performed, and a tan solid cylindrical structure longer than 2 cm was removed. Histopathologic examination revealed stratified squamous epithelium and soft tissue with substantial fibrosis and mild chronic inflammation, findings consistent with the characteristics of a remnant cast from a previous fistulous tract. Our findings suggest that some patients may benefit from relatively inexpensive sonographic examination with appropriate transducers. © 2002 Wiley Periodicals, Inc. J Clin Ultrasound 30: 557–561, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/jcu.10113