Fishbone is the most common foreign body among the population in Asia, the Mediterranean, and other coastal countries due to dietary habits . Generally, it is recommended to remove fishbone before they pass through the pylorus, otherwise 15–35% of them may perforate the intestine . The frequent lodging sites of fishbones in the upper digestive tract are palatine tonsil, base of the tongue, valleculae, the piriform sinus and the first narrow area of esophagus . It has been reported in a case that a toothpick was inserted into the common bile duct , but fishbone inserted into the duodenal papilla was never reported. Since the fishbone in our case was long and thin and very similar to a toothpick, we speculated that the fishbone might also be inserted into the common bile duct.
Patients with duodenal papillary foreign body may go through the acute stage and the chronic stage. At the acute stage, if there is a clear history of foreign body ingestion, the diagnosis is quick but the treatments may be different. Ouzhu M reported a dental prosthesis impacted in the duodenal papilla, which was then removed through endoscopy . Dias R also reported a metal pin removed by a surgical exploration of the duodenum . If the patients do not report a history of foreign body ingestion, both diagnosis and treatment will be difficult. Some foreign bodies may cause acute pancreatitis , while others may lead to ascending cholangitis . In addition, at the acute stage, some foreign bodies might be misdiagnosed as choledocholithiasis . At the chronic stage, some foreign bodies might form biliary stones, which may cause the cholangitis  or cholecystitis . Moreover, the foreign body may also cause chronic pancreatitis .
Although the fishbone was successfully and safely removed using a foreign body forceps, we still believed that endoscopic ultrasonography might be a good choice before the operation. Because the patchy erosion under the foreign body suggested that the fishbone might penetrate deeply. Lack of experience, we didn’t realize it was needed until we saw the length of the fish bone. This was also what we learned from this case. In addition, liver enzymes tests were also recommended because the patient had a biliary foreign body. It was worth noting that gastroscopy should be the first examination for patients with foreign bodies. If the endoscopist failed to carefully observe the duodenal papilla, the patient’s diagnosis would be tortuous.
In our case, the patient’s pain was localized to upper abdomen and was regularly aggravated after taking meals, which was similarly to the pain caused by a gastric ulcer. We suspected that it may be related to the increased duodenal peristalsis after meals. And the patchy erosion below the duodenal papilla was very likely caused by the swaying fishbone. Therefore, the patients with regular abdominal pain, not only the stomach but also the duodenal papilla are needed to be carefully examined.