Three cases of perianal abscesses due to foreign objects diagnosed by preoperative ultrasonography

Abstract

We describe our experience managing 3 cases with perianal abscesses caused by a foreign object, which was detectable on US. Two cases had a foreign object which had penetrated the internal and external anal sphincters, resulting in the formation of a perianal abscess. The other case had a foreign object which had penetrated the ischiorectal fossa, forming a perirectal abscess. The former 2 patients showed fistula-like findings with communication between the anal canal and the anal skin. Both underwent foreign object removal and radical surgery for anal fistula. The latter patient underwent foreign object removal and drainage only. All three patients had uneventful postoperative courses and achieved resolution of their conditions. Cases with a perianal abscess caused by a foreign object have rarely been reported. In most such reported cases, gastrointestinal tract perforation or penetration was diagnosed as the cause. However, primary opening similar to an anal fistula is occasionally observed when a foreign object penetrates the internal and external anal sphincters. In such cases, radical surgery for anal fistula needs to be considered, making preoperative diagnosis important.