A Case of Poorly Differentiated Adenocarcinoma with Signet Ring Cell Carcinoma of the Duodenal Bulb: A Case Report

Duodenal cancers are rare. Histopathologically, most duodenal cancers are adenocarcinoma. Signet ring cell carcinoma (SRCC) is a rare tumor more commonly found in the stomach than at other sites in the digestive tract. SRCC is extremely uncommon in the duodenum, with most of these tumors occurring in the ampulla. Until now, there are few case reports of duodenal cancers with SRCC. To accumulate case reports, we report a rare case of nonampullary duodenal bulb SRCC. A 74-year-old man was admitted to our hospital with melena. Esophagogastroduodenoscopy (EGD) showed a duodenal bulb ulcer. He was treated with a proton pump inhibitor. However, 1 month later, he was readmitted to our hospital with epigastric pain and nausea. A second EGD examination showed an ulcer at the duodenal bulb. Biopsies taken from the ulcer showed SRCC. Distal gastrectomy and duodenal bulb resection were performed. Histologic examination of the specimen showed a type 4 lesion located from the duodenal bulb to the pyloric antrum. The tumor was composed of poorly differentiated adenocarcinoma (por) with SRCC. The distal margin of the duodenal bulb was invaded with tumor. Therefore, pancreatoduodenectomy was performed. One year after the initial operation, he is alive and had no relapse. We described a rare case of por with SRCC of the duodenal bulb. It is important to bear in mind that an ulcer following an abnormal clinical course should be biopsied, and we have to select a suitable operation in cases of duodenal bulb cancer.