Ultrasound-guided percutaneous retrieval of an ischiorectal impacted ingested fish bone after failed surgical exploration: A case report and review of the literature.

Most ingested foreign bodies pass spontaneously through the gastrointestinal tract without incident. Sharp objects, such as fish or chicken bones, rarely perforate the bowel and migrate into adjacent soft tissues. A 36-year-old man presented with a 4-day history of worsening left perianal and buttock pain that began during defecation. Computed tomography revealed a linear foreign body in the left ischiorectal fossa. An initial ultrasound-guided retrieval attempt failed because the foreign body could not be confidently visualized on the scan. Subsequent anorectal examination under anesthesia and surgical exploration with fluoroscopic guidance also failed to localize and retrieve the object. Repeat ultrasound examination by a senior interventional radiologist faintly demonstrated the foreign body. Hydrodissection with a local anesthetic improved conspicuity and facilitated ultrasound-guided minimally invasive retrieval. Perianal and ischiorectal abscesses secondary to impacted/wall-penetrating ingested foreign bodies have been described, but migration of foreign bodies into the ischiorectal fossa without abscesses is exceedingly uncommon. To the best of our knowledge, image-guided percutaneous retrieval of such a foreign body has not been previously reported.