[Resection of carcinoma in situ and minimally invasive carcinoma of the pancreas in a patient presenting with stenosis and post-stenotic dilatation of the main pancreatic duct on endoscopic ultrasonography and positive serial pancreatic juice aspiration cytology].

We report a rare case of a 67-year-old man who underwent resection of carcinoma in situ and minimally invasive carcinoma of the pancreas. The patient presented with upper abdominal and back pain. No definite pancreatic mass was detected on abdominal ultrasonography, computed tomography, magnetic resonance imaging (MRI), or endoscopic ultrasonography (EUS). However, EUS and MRI demonstrated stenosis of the main pancreatic duct (MPD) in the body and post-stenotic dilatation, resulting in mild dilatation of MPD in the tail. Serial pancreatic juice aspiration cytology after endoscopic nasopancreatic drainage was suggestive of pancreatic adenocarcinoma. Examination of the distal pancreatectomy specimen demonstrated carcinoma in situ in MPD and branches, with multiple intraepithelial neoplastic lesions in the background pancreas and an additional focus of minimally invasive carcinoma.