The expression of claudin-4 was investigated in human pancreas, pancreatic ductal adenocarcinomas, and intraductal papillary-mucinous tumors of the pancreas (IPMT), and compared with that of claudin-1. In human adult pancreatic specimens, both claudin-1 and claudin-4 were immunohistochemically found in main and branching pancreatic ducts, terminal ductules and acinic cells, with the exception of endocrine cells. Of 12 cases of pancreatic ductal adenocarcinoma, 11 (92%) had positive immunostaining for claudin-4, and seven (58%) for claudin-1. In 44 lesions of 22 cases of IPMT, including six hyperplastic foci distant from the main lesions, clauidin-1 was positive in three out of six (50%) hyperplastic foci, 14 out of 17 (82%) adenomas, three out of 10 (30%) borderline tumors, two out of six (33%) non-invasive carcinomas, and one out of five (20%) invasive carcinomas, producing a statistically negative correlation with histological tumor grades. In contrast, claudin-4 was negative in the six hyperplastic foci, and positive in four out of the 17 (24%) adenomas, five out of the 10 (50%) borderline tumors, five out of the six (83%) non-invasive carcinomas, and four out of the five (80%) invasive carcinomas, producing a statistically positive correlation with histological tumor grades. On study of IPMT subtypes, claudin-1 was positive in nine out of 10 (90%) clear-cell types, seven out of 20 (35%) dark-cell types, and four out of eight (50%) compact-cell types. In contrast, claudin-4 was positive in two out of the 10 (20%) clear-cell types, 13 out of the 20 (65%) dark-cell types, and three out of the eight (38%) compact-cell types. These distinct expression patterns of claudin-1 and claudin-4 suggest that both claudins serve as useful molecular markers for the tumor classification of IPMT.

Most cases of small-cell neuroendocrine carcinoma in the duodenum show rapid progression of the disease, and even radical surgery with or without chemotherapy do not prevent death. We report a rare subtype of small-cell neuroendocrine carcinoma. This subtype appears to have a much better prognosis, and may be amenable to local excision, if the lesion is away from the ampulla of Vater.

This case highlights that a pancreatogastric fistula can develop after acute inflammation of the pancreas in the absence of cancer invasion. Further information regarding IPMN-associated fistulae is necessary to clarify the pathogenesis, diagnosis, appropriate surgical intervention and prognosis for this disorder.

Compared with conventional ERP or RP, CT-VP and 3D-CT pancreatographic images were finer in quality, and the procedures were less invasive, faster, and less expensive. The potential shown by CT-VP with 3D-CT pancreatography in the clinical diagnosis of pancreatic IPMNs suggests that this approach may replace ERP in the near future.

The treatment of intraductal papillary mucinous tumors (IPMT) of the pancreas is still controversial. In this report we describe a single-branch resection of the pancreas (SBRP), which is a new method for the removal of branch-type IPMT of the head of the pancreas. A multilobular cystic lesion (50 x 40 mm) in the head of the pancreas was incidentally detected in an asymptomatic 40-year-old man who underwent a routine ultrasound examination. The tumor was carefully removed along the border of the cyst and the normal parenchyma, with complete preservation of the main pancreatic duct and the common bile duct. A pancreatic fistula developed during the postoperative period, but was well-controlled by endoscopic naso-pancreatic drainage. SBRP is a technically feasible procedure and this operation represents a minimally invasive alternative to any other segmental resection of the pancreas.