Abstract
Background : Intraductal papillary-mucinous tumor (IPMT) of the pancreas has a broad spectrum of histology ranging from hyperplasia to adenocarcinoma. Therefore, it is important to differentiate between the malignant and benign lesions to determine the therapeutic strategy for IPMT. Patients and Methods : Thirty-nine patients with IPMT (27 men and 12 women, mean age : 63.3 years) underwent surgery between January 1985 and March 2002. The size of the cystic lesion, the maximum diameter of the main pancreatic duct (MPD), and the height of the papillary tumor inside the cyst were investigated by endoscopic ultrasonography (EUS) and/or intraductal ultrasonography (IDUS) before operation. These preoperative clinical findings were compared with the pathological findings of the resected specimen. Results : The size of the cystic lesion, the diameter of MPD, and the height of the papillary tumor in cases with malignant IPMT (invasive and non-invasive carcinoma) were larger than those in cases with benign IPMT (adenoma and hyperplasia). Analysis of the images of the lesions revealed that the following three factors are important for diagnosing IPMT : (i) the size of the cystic lesion is > 30mm ; (ii) the diameter of MPD is > 8mm ; (iii) the height of the papillary tumor inside the cyst is >3mm. It was not significant to differentiate between benign and malignant IPMT based on factor (i), but statistically significant (p <0.001) based on factors (ii) and (iii). Conclusions : EUS and IDUS are useful in the differential diagnosis of IPMT, especially in the differentiation between malignant and benign IPMT.
