Pancreatic intraductal tubulopapillary neoplasm with associated invasive cancer successfully treated by total pancreatectomy: A case report.

A 74-year-old male was admitted to Departments of Surgery, Toyonaka Municipal Hospital (Osaka, Japan) for treatment of a pancreatic tumor. Contrast enhanced computed tomography (CT) revealed a mass with small cystic lesions in the pancreatic head and body. Fluorodeoxyglucose-positron emission tomography/CT revealed an abnormal uptake of fluorodeoxyglucose, corresponding to the mass lesions. Upper gastrointestinal endoscopy revealed rough mucosa near the opening of the accessory pancreatic duct, and the mucosa biopsy exhibited adenocarcinoma with no mucin observed. The preoperative diagnosis was pancreatic intraductal tubulopapillary neoplasm (ITPN) with cancerous lesions, and a total pancreatectomy with splenectomy was performed. The resected tissue specimen revealed a solid tumor occupying the entire pancreas with intraductal growth into the main pancreatic duct. Histological examination revealed high-grade dysplastic cells in a tubulopapillary growth pattern without overt mucin production beyond the pancreatic duct. Immunohistochemical staining analysis of the tumor was positive for cytokeratin (CK)7, CK19 and mucin (MUC)1, and negative for MUC2, MUC5AC, MUC6 and caudal type homeobox 2. The tumor was finally diagnosed as pancreatic ITPN with associated invasive cancer. The patient remains well without evident recurrence nine months post-surgery. ITPN is a rare type of epithelial neoplasm of the pancreas, and is characterized by intraductal tubulo-papillary growth, ductal differentiation, limited intracellular mucin production, and cellular dysplasia. The present case report may contribute to improved understanding of how to effectively treat patients with ITPN.