[A case of duodenal perforation due to ingested fishbone with retroperitoneal abscess formation where surgical...

A female in her 60s was referred to our institution with epigastric pain and abdominal fullness persisting for one week. She was afebrile and mild abdominal tenderness was found on physical examination. Computed tomography (CT) revealed free air, and the dirty fat sign outside the duodenal wall. Her previous CT had not shown causative findings such as duodenal diverticula. A slightly high-attenuated linear structure penetrating the duodenal wall at the second portion was suspected after review of present CT images. Based on the history of her current illness, the possibility of mackerel bone ingestion was considered. Esophagogastroduodenoscopy (EGD) revealed a fishbone sticking out of the duodenal wall, which was extracted with biopsy forceps. Although antibiotic treatment under fasting was continued, the formation of retroperitoneal abscess was detected by CT on the 6th postprocedural day. Given that she also developed a high fever, surgical drainage was performed. The patient was discharged on the 15th postoperative day. Thus, in cases of duodenal perforations, a fishbone should be taken into account as a possible cause. Even if endoscopic removal was initially selected, careful observation is mandatory and an additional treatment should be considered depending on the clinical course.