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. Cancer 68:159-168,1991.

To evaluate diagnostic accuracy of endoscopic ultrasonography (EUS) on the extent of carcinoma of the papilla of Vater, 28 patients were preoperatively evaluated using our EUS grading system. EUS was accurate in diagnosing carcinoma infiltration into the duodenal proper muscle layer (100o/o) and into the pancreas (75%). When compared with postoperative histologic findings, the overall accuracy of EUS in assessing local infiltration C arcinoma of the papilla of Vater has frequently been reported to have relatively good prog· nosis, 1 whereas advanced cases are known to have poor prognosis. 2 To achieve a better prognosis, the most appropriate surgical procedure should be selected through careful consideration of the stage of carcinoma. Preoperative diagnosis by conventional modalities, however, cannot satisfactorily determine the extent of carcinoma in the papilla for two reasons: Tumor size is usually small, and site of generation of the carcinoma is anatomically very complicated. Conventional imaging modalities are limited in that they cannot obtain clear images of the tumor nor determine its relation to the structure of the duodenal wall and adjacent pancreas. Received September 11, 1989, from the •second Department of In· temal Medicine, Nagoya University School of Medicine, Nagoya, Japan; and the tDepartment of Internal Medicine, School of Medicine, Fujita·Gakuen Health University. The Second Hospital. Nagoya, Japan. Revised manuscript accepted for publication April 11, 1990.Address correspondence and reprint requests to Dr. Mitake: The Second Department of Internal Medicine, Nagoya University School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466, Japan . . was 89.3%. Misdiagnoses occurred in three cases due to microinfiltration of the carcinoma. Lymph node metastasis around the pancreatic head was accurately diagnosed in nine cases; however, mesenteric lymph node metastasis could not be detected in four cases because the tumor was far from the scanning site. KEY woRos: endoscopic sonography; carcinoma of the papilla of Vater, diagnosis of extent. (/ Ultrasound Med 9:645, 1990) Endoscopic ultrasonography (EUS) can solve these problems because high-resolution images can be obtained with a high-frequency probe placed dose to the target organ. The usefulness of EUS has already been reported in diagnosing cancer of the digestive tract and the pancreas. •4 It has also been demonstrated that clear images of the papilla of Vater, structure of the duodenal wall, peripapillary pancreatic duct, and common bile duct can be obtained by EUS. This allows for better diagnosis as to the extent of tumor invasion into the duodenum and the pancreas, as well as visualization of the lymph nodes around the head of the pancreas.5.6The purpose of this study is to evaluate the effectiveness of EUS in diagnosing the extent of carcinoma of the papilla of Vater by comparing preoperative diagnoses by EUS with histologic findings obtained from postoperative tissue specimens. SUBJECTS AND METHODSBetween january 1985 and December 19...

Intraductal ultrasound (IDUS) probes mounted with 30 MHz or 20 MHz transducers were evaluated in the diagnosis of 239 patients with pancreatic disease (including 48 cancers, 90 mucin-producing tumors, seven islet-cell tumors, two metastatic pancreatic tumors, seven serous cystadenomas, one pancreatic teratoma, three solid cystic tumors, 49 cases of chronic pancreatitis, 25 cases of focal pancreatitis, and seven cases of pancreatolithiasis). The probe was inserted via the papilla into the main pancreatic duct. In terms of resolution, IDUS at 20 MHz was able to image cystic lesions of less than 30 mm in diameter and solid lesions of less than 20 mm in diameter. With regard to vessels, IDUS was able to image the entire cross-section of the portal vein and other large veins. IDUS was useful in detecting carcinoma in situ and small tumors, in assessing the intraductal spread of the tumor and its pancreatic parenchymal invasion in mucin-producing tumors of the main duct, and in assessing the indications for surgery by revealing mural nodules in mucin-producing tumors of the ductal branches. IDUS was also useful in evaluating the feasibility of partial resection of the tumor in mucin-producing tumors of the ductal branches and pancreatic islet-cell tumors, in accurately locating multiple lesions in pancreatic islet-cell cancer, and in differentiating benign from malignant cases of localized stenosis of the main pancreatic duct related to pancreatic stenting. With IDUS, the site of pancreatic stones could be identified in order to assess the need for endoscopic treatments such as stenting of the pancreatic duct and the bile duct, and the use of pulsed-dye laser treatment under pancreatoscopy for pancreatic stones. Acute pancreatitis as a complication occurred in one of the 239 patients who underwent IDUS (0.4%). An awareness of the limitations and usefulness of IDUS in evaluating pancreatic diseases can contribute to the treatment of these conditions.