Mucin-producing tumor of the pancreas - Intraluminal ultrasonography

BACKGROUND/AIMS: Many patients with mucin-producing pancreatic tumor, characterized by dilatation of the pancreatic duct, are diagnosed by conventional ultrasonography in a mass ultrasonographic survey in Japan. It is a necessary and reliable method for making a precise diagnosis and for deciding on the treatment approach. Endoscopic ultrasonography (EUS) is appreciated as a useful method for precise diagnosis of pancreatic tumors. Intraductal ultrasonography (IDUS) is expected to be a new modality for the more detailed diagnosis of pancreatic tumors. METHODOLOGY: Endoscopic ultrasonography and intraductal ultrasonography were performed in 23 patients with mucin-producing pancreatic tumor. The differences in ultrasonographic findings between benign and malignant tumors were studied. RESULTS: Ultrasonographic findings of mucin-producing pancreatic tumor revealed by EUS and IDUS were: cystic lesion, mural nodule in the cystic lesion, wall thickness of the cyst, mucus echoes, and solid tumor with a mixed echo pattern. Seven out of 11 patients with mural nodule were diagnosed as carcinomas and another 4 patients had adenoma. Seven of 8 patients with mucus echoes were diagnosed as carcinoma. Three of 4 patients with solid tumor were diagnosed as invasive carcinoma. The ultrasonographic findings suggesting malignancy were: mural nodule, irregular wall thickness, mucus echoes, and solid tumor with a mixed pattern. Solid tumor indicated invasive carcinoma exclusively. CONCLUSIONS: Intraluminal ultrasonography, EUS and IDUS are very useful in making a differential diagnosis between benign and malignant tumors in mucin-producing pancreatic tumors.