Yuichiro Kato

The patient was a 61-year-old male who was referred to our hospital after dilatation of the main pancreatic duct was detected by screening ultrasonography. Computed tomography revealed a protruding lesion measuring 15 mm in diameter within the main pancreatic duct in the head of the pancreas, and magnetic resonance cholangiopancreatography revealed interruption of the duct at the tumor site. We performed pancreaticoduodenectomy under a suspected diagnosis of invasive ductal carcinoma. Gross examination of the resected specimen showed that the tumor invaginated into the main pancreatic duct, and no mucin was found. Histological examination revealed proliferation of high-grade dysplastic cells in a tubulopapillary growth pattern. Immunohistochemically, cytokeratin 7 expression was detected, but not trypsin expression. Based on these morphological features, we diagnosed the tumor as intraductal tubulopapillary neoplasm (ITPN). We report the case with bibliographic consideration, together with a review of intraductal neoplasms of the pancreas encountered at our institution.

A 71-year-old woman was referred to our institution for further investigation of epigastric pain. The patient had been detected to have a multilocular cyst in the medial segment of the liver measuring 69 mm in diameter at another hospital 2 years ago, and the diameter of the cyst had increased to 90 mm. Although the cyst had gradually increased in size, there was no evidence of mural nodules. As we were concerned about the malignant potential of the lesion, a left hepatic segmentectomy was performed. Pathologically, the cyst was lined by columnar and cuboidal epithelium with low-grade atypia. The epithelium covered an ovarian-like stroma, and the diagnosis was mucinous cystic neoplasm of the liver (MCN-L) with low-grade intraepithelial neoplasia. MCN-L is a rare disease and its characteristics are still poorly understood. MCN-L occurs at a lower frequency as compared to the counterpart of MCN of the pancreas, further investigations are necessary to clarify the biological malignancy of MCN-L.

Background: The international consensus guidelines for the management of intraductal papillary mucinous neoplasm (IPMN) of the pancreas were revised in 2012 Tanaka (Pancreatology 12(3):183–197, 2012), making the indications for operation less aggressive. Therefore, the number of branch duct‐type IPMN (BD‐IPMN) patients requiring follow‐up care is expected to increase in the future.Methods: The aim of this study was to identify risk factors for malignancy in BD‐IPMN patients during the follow‐up period. This study included 47 BD‐IPMN patients without a mural nodule (MN) at the time of initial diagnosis and who subsequently underwent resection after a follow‐up period of more than 3 months. Data for the patients were reviewed retrospectively, and the clinicopathological factors were investigated.Results: In a univariate analysis, age (≧65 years), an increase in the main pancreatic duct (MPD) diameter, the MPD diameter at resection (≧5 mm), and the occurrence of MN were significantly associated with malignancy. The occurrence of MN was the only significant factor in a multivariate analysis. In addition, 7 of the 17 patients (41.2 %) who only exhibited an increase in the cyst diameter during the follow‐up period were diagnosed as having malignancies. All 6 patients who exhibited an increase in the cyst diameter of 100 % or more were diagnosed as having carcinoma.Conclusions: During the follow‐up period, the incidence of malignancy was higher among patients with BD‐IPMNs and the occurrence of MN, an increase in the MPD diameter, or an increase ratio of 100 % or more in cyst diameter than the others; resection was recommended for these patients.

Duodenal cancer excluding Vater's papilla cancer is a relatively rare disease entity; therefore, the most appropriate operative methods depending on the tumor condition, such as the tumor site and/or depth of invasion, still remain unclear. The aim of this study is to determine an appropriate operative method and an appropriate extent of lymph node dissection depending on tumor site or tumor invasion depth. Data of a total of 35 patients with duodenal cancer who underwent resectional surgery with curative intent were reviewed retrospectively, and the clinicopathological factors and survival outcomes were investigated. Overall 5-year survival rates of all resected cases were 63.0% (median survival: 9.1 years). Multivariate analysis identified histological G3/4 (P = 0.002) and presence of lymph node metastasis (P = 0.004) as independent adverse prognostic factors. Of the 35 patients, 11 (31.4%) had lymph node metastasis. In all patients with the tumor invasion depth within limited to the mucosa or submucosa (T1a or T1b), lymph node metastasis was absent (0/15 patients). T2/3/4 tumor (P < 0.001) and G3/4 (P = 0.021) were identified as predictors of the presence of lymph node metastasis. Four (11.4%) of the 35 patients had metastasis in the infrapyloric node. Limited resection is sufficient for patients with T1a tumor. In the case of T1b tumor, limited resection or pancreatoduodenectomy may be selected after performing pancreaticoduodenal node biopsy as sentinel lymph node biopsy. For patients with T2–4 tumor, pancreatoduodenectomy or substomach preserving pancreatoduodenectomy (excepting Pylorus-preserving pancreatoduodenectomy) with regional lymph node dissection should be performed.

We report a rare case of an intraductal oncocytic papillary neoplasm (IOPN) of the extrahepatic bile duct. A 66-year-old man was admitted to our hospital for investigation of right-sided back pain. Ultrasonography, computed tomography and magnetic resonance imaging showed a papillary lesion, 3 cm in diameter, in the middle bile duct, invaginating into the cystic duct. We made a provisional diagnosis of middle bile duct cancer and performed substomach-preserving pancreatoduodenectomy. Macroscopically, the middle bile duct contained a two-humped papillary tumor, one tip of which invaginated into the cystic duct. Microscopically, the tumor consisted of cuboidal cells with abundant eosinophilic cytoplasm resembling that of oncocytes and a fine fibrovascular core. The tumor cells were stained strongly with antimitochondria antibody. Based on these findings, the tumor was diagnosed histologically as IOPN of the extrahepatic bile duct. The patient died of prostate cancer 51 months after surgery, but without evidence of recurrence of the IOPN.