Intraductal tubular carcinoma in an adenoma of the main pancreatic duct of the pancreas head.

A 50-year-old woman presented with intermittent diarrhea and upper abdominal pain. Laboratory data showed elevated serum amylase and elastase-I levels. Further image studies revealed a small, well-defined nodular lesion (8 mm in diameter) without mucin hypersecretion in the main pancreatic duct (MPD) of the pancreatic head and subsequent dilatation of the distal main pancreatic duct. A pylorus-preserving pancreatoduodenectomy with regional lymphadenectomy was performed. Microscopically, the tumor was an intraductal tubular carcinoma (ITC) in a tubular adenoma, suggesting direct histologic evidence of the adenoma-carcinoma sequence in intraductal tubular tumors, differing from previous reports of ITCs describing de novo-like development. The prognosis for ITC patients is sometimes dismal; therefore, early detection and appropriate surgical resection are mandatory to achieve long-term survival in ITC patients. MPD dilatation is a crucial sign and clue enabling the early detection of tiny pancreatic tumors.