Intraductal papillary mucinous neoplasm mimicking a duodenal tumor.

Intraductal papillary mucinous neoplasms of the pancreas are characterized by ductal dilatation, mucus secretion, and intraductal papillary growth. Intraductal papillary mucinous neoplasms can cause fistulation and extend to adjacent organs. However, they rarely present as large mass in the small bowel that causes bowel obstruction. Herein, we describe a case of intraductal papillary mucinous neoplasm that protruded into the duodenal lumen through the ampulla of Vater, presented as a large duodenal tumor, and developed duodenal obstruction. A 78-year-old woman was admitted to the emergency department with a 2-day history of vomiting and epigastric pain and 2 kg weight-loss in 2 months. Esophagogastroduodenoscopy showed a duodenal mass; however, the endoscope could not pass further, and visualization of the entire tumor was impossible. Computed tomography and magnetic resonance imaging revealed a heterogeneous enhancing mass measuring 8 cm in the second portion of the duodenum, which continued further as an intraductal mass of the pancreas. The main pancreatic duct was dilated, and the parenchyma was atrophied. The biopsy showed a well-differentiated adenocarcinoma and an intact overlying duodenal mucosa. Surgical option of treatment was offered to the patient; however, she refused it due to her advanced age and personal religious beliefs. Thus, we conclude that the experience and knowledge gathered through this patient regarding intraductal papillary mucinous neoplasms could provide further understanding of this disease and evolve subsequent patient care.