title: A pancreatobiliary-type carcinoma in situ at the periphery of a mural nodule developed from a gastric adenoma in an intraductal papillary mucinous neoplasm.
abstract: We report a rare case of an intraductal papillary mucinous neoplasm (IPMN) with a pancreatobiliary-type carcinoma in situ (CIS) that originated around a mural nodule formed in a gastric-type adenoma. A 64-year-old man was admitted to our hospital in December 2001 for dilation of the main pancreatic duct, detected on abdominal ultrasonography. Branch-duct-type IPMN (diameter 25 mm) was diagnosed, and because mural nodules were absent, the patient was annually followed up for 5 years. In 2006, computed tomography scans revealed thickening of the tumor wall and the development of a mural nodule (diameter approximately 6 mm); pancreatoduodenectomy with regional lymph-node dissection was performed. Histopathologic examination showed an intraductal papillary mucinous carcinoma arising from an adenoma. Hematoxylin and eosin (H&E) staining revealed that most of the tumor components, including the mural nodule, had adenomatous changes, indicating the tumor to be of the gastric type; however, immunohistochemistry showed positive MUC2 expression. Histologically, the tissues around the nodule, including those showing a cribriform pattern, were diagnosed as CIS. These tissues were classified as the pancreatobiliary-type on the basis of the results of both H&E staining and immunohistochemistry. The patient remained disease-free for 3 years after surgery.
authors.affiliation: Department of Gastroenterological General, Breast and Thyroid Surgery, Faculty of Medicine, Yamagata University, 2-2-2 Iida-Nishi, Yamagata, 990-9585, Japan. takasu-jaem@umin.ac.jp.
authors.forename: Naoki
authors.initials: N
authors.lastname: Takasu
authors.affiliation: Department of Gastroenterological General, Breast and Thyroid Surgery, Faculty of Medicine, Yamagata University, 2-2-2 Iida-Nishi, Yamagata, 990-9585, Japan. wkimura@med.id.yamagata-u.ac.jp.
authors.forename: Wataru
authors.initials: W
authors.lastname: Kimura
authors.affiliation: Department of Gastroenterological General, Breast and Thyroid Surgery, Faculty of Medicine, Yamagata University, 2-2-2 Iida-Nishi, Yamagata, 990-9585, Japan. tmoriya@med.id.yamagata-u.ac.jp.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Moriya
authors.affiliation: Department of Gastroenterological General, Breast and Thyroid Surgery, Faculty of Medicine, Yamagata University, 2-2-2 Iida-Nishi, Yamagata, 990-9585, Japan. atakesit@med.id.yamagata-u.ac.jp.
authors.forename: Akiko
authors.initials: A
authors.lastname: Takeshita
authors.affiliation: Department of Gastroenterological General, Breast and Thyroid Surgery, Faculty of Medicine, Yamagata University, 2-2-2 Iida-Nishi, Yamagata, 990-9585, Japan. s-murayama@med.id.yamagata-u.ac.jp.
authors.forename: Saijiro
authors.initials: S
authors.lastname: Murayama
authors.affiliation: Department of Gastroenterological General, Breast and Thyroid Surgery, Faculty of Medicine, Yamagata University, 2-2-2 Iida-Nishi, Yamagata, 990-9585, Japan. ihirai@med.id.yamagata-u.ac.jp.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Hirai
authors.affiliation: Department of Human Pathology, Faculty of Medicine, Yamagata University, 2-2-2 Iida-Nishi, Yamagata, 990-9585, Japan. siogata@med.id.yamagata-u.ac.jp.
authors.forename: Shinya
authors.initials: S
authors.lastname: Ogata
keywords: Growth pattern; Intraductal papillary mucinous neoplasm; Mural nodule; Subtype