Gastrocolocutaneous fistula detected by [¹⁸F]fluorodeoxyglucose positron emission tomography with low-dose computed tomography: a rare iatrogenic complication of colonoscopy.

Colonoscopy is generally considered to be a low-risk procedure. The incidence of iatrogenic perforation during diagnostic colonoscopy is less than 1.0% [1]. The development of a gastrocolocutaneous fistula is a very rare complication of a perforation inflicted during an endoscopic procedure. We present the case of a 48-year-old man whowas referred for [18F]fluorodeoxyglucose positron emission tomography with low-dose computed tomography ([18F] FDG-PET/CT) because of fever, abdominal discomfort, and pyogenic discharge from his abdominal wall. His medical history reported an amputation of the fifth digit of his left foot and percutaneous transluminal angioplasty with endovascular grafting of the left common iliac artery (CIA), pseudomembranous colitis due to antibiotics given because of a wound infection at the amputation site, iatrogenic perforation during colonoscopy resulting in subtotal colectomy with placement of a permanent ileostomy, and eventually abdominal abscesses, which were drained and treated with penicillin. Three months after surgery, the patient was still suffering from fever and a fluidleaking laparotomy wound. An [18F]FDGPET/CT scan was performed to exclude an infection of the endovascular prosthesis in the left CIA (●" Fig.1,●" Fig.2). Surprisingly, the scan showed a large fistula originating from the greater curvature of the stomach, with a branch towards the anterior abdominal wall, as well as a branch towards the descending part of the colon. There was no suspicion of involvement of the graft in the CIA or the tissue surrounding it. [18F]FDG-PET/CT is a useful clinical tool for investigating potentially infected vascular prostheses, with high diagnostic accuracy [2]. The available literature suggests better test characteristics than for CT alone [3]. Its role in fistulas is not yet well established, but is increasing [4,5]. Given its high accuracy in infectious diseases, [18F] FDG-PET/CT may be assumed to have high potential for visualizing fistulas. Endoscopy_UCTN_Code_CPL_1AJ_2AG