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Aim: To compare the clinico-pathological features of intraductal papillary mucinous cystic tumours (IPMT) and mucinous cystic tumours (MCT) of the pancreas., Methods: Eighteen patients with IPMT and 18 with MCT who underwent surgical resection between 1990 and 2004 were retrospectively reviewed. Their clinico-pathological features were compared using univariate analysis. Statistical analyses of potential predictive factors of malignancy for each of these two groups were also conducted., Results: Patients with IPMT were found to be older (64+/-10 vs 43+/-18 years, p<0.001) and were predominantly male (male:female ratio, 5:4 vs 1:17, p=0.003) as compared to patients with MCT. MCTs were found in the body-tail region (100%) whereas IPMTs were more evenly distributed (50% in the head) (p=0.001). Pathologically, IPMT was distinct from MCT in terms of size (3.8+/-3.2 vs 9.1+/-4.4 cm, p=0.001), association with secondary pancreatitis (50 vs 0%, p=0.011), communication with the pancreatic duct (94 vs 0%, p<0.001), presence of a dilated main pancreatic duct (61 vs 0%, p<0.001) and the presence of ovarian-type stroma (0 vs 44%, p=0.003)., Conclusion: IPMT and MCT are distinct clinico-pathological entities. This distinction is important as management and outcome of these entities may differ.

Background/aims: Segmental pancreatectomy for benign tumors of the neck of the pancreas was reported in 1993. Mucin-producing carcinomas are generally regarded as low-grade malignancies as compared with ductal cell carcinomas of the pancreas. We report herein our experience with a segmental pancreatectomy for mucin-producing pancreatic tumors., Methodology: Three patients with mucin-producing tumors of the pancreatic body underwent a segmental pancreatectomy. After the pancreatic tumor had been located with intra-operative ultrasonography (US), the medial pancreas centered on the tumor was resected. The margin of the retained pancreas was submitted for histopathologic inspection intra-operatively to prevent retained disease. A conduit for draining the pancreatic juice consisted of a jejunal Roux-en-Y loop between the left and cephalic portions of the pancreas. Histologically, the 3 tumors were identified as a cystadenocarcinoma, an intraductal papillary adenocarcinoma, and a cystadenoma with a focus of borderline malignancy. The functional result was evaluated with oral glucose tolerance and pancreatic function diagnostic (PFD) testing. Pancreatic juice drainage was confirmed using magnetic resonance cholangiopancreatography (MRCP)., Results: Neither technical failure nor operative death occurred in any of the patients. The patients have been followed-up for between 33 months and 77 months after surgery and all are disease free. The oral glucose tolerance test and PFD test results were all within the normal range. MRCP showed good pancreatic juice drainage in the 2 patients examined., Conclusions: Segmental pancreatectomy may be an appropriate surgical procedure for mucin-producing pancreatic tumors, to prolong survival and to preserve endocrine and exocrine function.

We have previously reported that MUC2 apomucin was highly expressed in noninvasive tumors of the pancreas (intraductal papillary tumor [IdPT]) and liver (bile duct cystadenocarcinoma [BdCC]), which show more favorable outcomes than invasive carcinomas. In contrast, MUC2 was rarely expressed in invasive carcinomas of the pancreas (invasive ductal carcinoma [IDC]) and the liver (invasive cholangiocarcinoma [ICC]). In the present study, we examined localization of MUC2 messenger RNA (MUC2 mRNA) by using a complementary DNA (cDNA) probe for the MUC2 tandem repeat for in situ hybridization (pHAM1). Localization of MUC2 apomucin was determined by using an antibody directed against MUC2 apomucin (anti-MRP) for immunohistochemistry study. Eleven IdPTs and 10 IDCs of the pancreas, and 8 BdCC and 8 ICCs of the liver were examined. Nine (82%) of 11 IdPTs showed positive expression of MUC2 mRNA in the neoplastic cells, whereas none (0%) of the IDCs showed expression of MUC2 mRNA. Six (75%) of the 8 BdCCs showed positive expression of MUC2 mRNA in the neoplastic cells, whereas none (0%) of the 8 ICCs showed expression of MUC2 mRNA. The localization of MUC2 mRNA and that of MUC2 apomucin usually coincided, although a few cases (1 IDC, 1 BdCC, and 1 ICC) showed focal expression of MUC2 apomucin despite the absence of detectable MUC2 mRNA. These results indicate that the expression of MUC2 apomucin in IdPTs and BdCCs correlates with expression of MUC2 mRNA. In both patient groups with pancreatic tumors and hepatic tumors, patients with positive MUC2 mRNA expression in the tumors showed significantly better survival than those with negative MUC2 mRNA expression in the tumors. The production of MUC2, an abundant extracellular mucin, by most IdPTs and BdCCs may be correlated with tumors that display lower levels of invasion and metastasis.

Nuclear DNA content in eight surgically resected mucin-producing pancreatic tumors (MPPT) consisting of two mucinous intraductal adenocarcinomas (MIDAC), two mucinous intraductal adenomas (MIDA), one mucinous cyst-adenocarcinoma (MCAC), and three mucinous cystadenomas (MCA) were measured by flow cytometry using paraffin-embedded tissue samples. The technique of Shutte was used for the preparation of paraffin-embedded tissue into single dissociated nuclei, while the method of Vindelov was used for staining the isolated nuclei with propidium iodine. Clinicopathologically, the four patients with MIDAC or MIDA were all male and had cystic lesions with a dilated pancreatic duct at the head of the pancreas, while the four patients with MCAC or MCA were all females and had cystic tumors at either the body or tail of the pancreas. All eight patients with MPPT had no metastasis to the regional lymph nodes and were all still alive without recurrence. In an analysis of nuclear DNA content, seven of eight patients had DNA diploid tumors while one patient with a MIDAC perforating the duodenum and choledochus had a DNA aneuploid tumor. Thus, these findings suggest that DNA diploid patterns in MPPT might be associated with a favorable prognosis in MPPT although some patients whose MPPT invaded the surrounding organs might have DNA aneuploid tumors.

Patient records, imaging films, macroscopic and microscopic features, and clinical follow-up data of seven Japanese patients with a mucin-hypersecreting tumor of the pancreas were reviewed. The mucin-hypersecreting tumor was defined as an enlarged major or minor papilla with a dilated orifice and visible mucin oozing on endoscopy. The series consisted of six men and one woman ranging from 47 to 79 yr old. The excretion of mucin through a patulous orifice of the enlarged ampulla of Vater was seen in six patients and of the enlarged minor papilla in the other patient with pancreas divisum. The main pancreatic duct was dilated in all patients. Amorphous mucin was seen in the dilated duct of five patients, and papillary nodules were present in two patients. Computed tomography and/or ultrasonography showed dilatation of the main pancreatic duct with multilocular cysts in six patients and with a solid tumor in the other patient. The tumor was located diffusely in the main pancreatic duct in one patient, whereas it was confined to branches in the head (four patients), body (one patient), or tail (one patient) of the pancreas in the six other patients. Histopathologic diagnosis was a cyst lined by hyperplastic mucus-secreting epithelium in one patient, mucinous cystadenoma in two, and mucinous cystadenocarcinoma in two. Five patients underwent resection and have survived for 1-46 months after the operation. The authors would like to emphasize this endoscopic syndrome because about half of mucin-hypersecreting tumors are malignant with a favorable prognosis.

A new pancreatic tumor, called mucin-producing tumor, has received great attention in Japan. These tumors are found inside the pancreatic duct and produce large quantities of copious mucus. The authors examined 22 cases of these tumors histologically and histochemically. In 12 malignant cases, the tumors inside the ducts consisted of cancerous lesions over small areas along with papillary or atypical hyperplasia. Tumors in ten benign cases mainly consisted of papillary hyperplasia. Except for three patients with carcinoma in situ, cancerous tumors infiltrated the pancreatic parenchyma and, in some cases, were observed invading the bile duct or duodenum. A mucous histochemical study showed evidence of sialomucin in malignant cases; neutral mucin was dominant in benign cases. Characteristics of this disease were also compared with 13 cases of mucinous cystic neoplasm. From the results, it was concluded that these two diseases can be classified into the same conceptual category.

True cystic neoplasms of the pancreas generally have mucinous, glycogen-rich, or acinar-type-cyst-lining epithelium. A malignant polycystic pancreatic neoplasm in a 74-year-old black woman whose cyst-lining epithelium had none of the above-cited attributes and thus appears to represent an exception is described. The primary tumor was a large, encapsulated mass whose cysts contained watery fluid. Basically, two types of epithelium lined the cysts: a single layered, low-grade malignant-appearing type and a proliferative, overtly malignant-appearing pseudostratified and papillary type. Oncocytic metaplasia, canaliculi, and microvilli were ultrastructural features.

A cystadenoma or a cystadenocarcinoma arising from the renal pelvis is a rare neoplasma and, so far as is known, only two cases have been reported in the literature (Arcadi, 1956, and Ross, 1985). Discussed herein is a case of a 63-year-old woman who developed a mucinous nephrosis, due to a marked retention of mucin produced by a tumor. The ureter as well was found to be involved. The histogenesis of an adenocarcinoma, which includes a cystadenoma and a cystadenocarcinoma, most likely is due to a glandular metaplasia, associated with urolithiasis and pyelonephritis. In this specific case, the patient revealed a history, fifteen years earlier, of renal calculi and pyelonephritis.

Obstruction of the biliary tree by large amounts of mucinous material is reported in a patient with a mucin-producing cystic adenocarcinoma of the pancreas invading the common bile duct. Although preoperative endoscopic retrograde cholangiography suggested bile duct invasion, mucinous obstruction, as in the previous cases in which it has been reported, was not suspected. Mucinous obstruction, although unusual, should be considered in patients with cystic carcinomas of the pancreas in the presence of jaundice or episodes of cholangitis.

The radiologic findings are described in six patients with "mucin-hypersecreting" intrahepatic biliary neoplasms (biliary cystadenocarcinoma or papillary cholangiocarcinoma). Massive amounts of mucin were confirmed in the dilated bile ducts at surgery or autopsy. Computed tomography (CT) and ultrasound (US) demonstrated severe dilatation of the intrahepatic bile ducts distal to the tumor in all patients and of extrahepatic ducts in five. On cholangiograms, large, amorphous filling defects caused by retention of mucin were found in the dilated ducts in three patients. The tumor was multilocular and cystic in five patients; in the other patient it was too small to be detected at CT or US. The presence of liver tumor (mostly multilocular and cystic), marked biliary dilatation distal to the tumor, and filling defects in the dilated bile ducts are important findings that indicate a mucin-hypersecreting intrahepatic biliary neoplasm.