Resection of four synchronous invasive ductal carcinomas in the pancreas head and body associated with pancreatic intraepithelial neoplasia: Report of a case

This report describes a very rare case of four synchronous invasive ductal carcinomas (IDCs) in the pancreas head and body with possible multicentricity. The patient was a 75-year-old woman. Abdominal dynamic computed tomography showed four low-density masses (25 mm, 20 mm, 10 mm, and 10 mm in diameter) in the pancreas head and body. The patient underwent a pylorus-preserving subtotal pancreatoduodenectomy. Histologically, the discontinuity between the four tumors was confirmed; one tumor (20 mm) was moderately differentiated tubular adenocarcinoma, and the others (25 mm, 10 mm, and 10 mm) were papillary adenocarcinomas. Two smaller papillary adenocarcinomas were composed of abundant fibrosis, pancreatic intraepithelial neoplasia (PanIN) 2-3, and IDC with stromal invasion. PanIN-1-2 lesions proximal to the four IDCs were evident. The immunohistochemical staining by CK20, MUC1, and Ki-67 revealed apparently different features for 2 IDCs (25 mm and 20 mm) and somewhat differential features for three papillary adenocarcinomas. Therefore, the progression of PanIN to IDC and multicentric occurrences of these four IDCs were possible. In this report, we show that immunohistochemistry and the confirmation of the presence of PanINs in IDC were useful to some extent for the study of multiple pancreatic cancers.