INTRADUCTAL PAPILLARY-MUCINOUS NEOPLASM OF THE PANCREAS - A CLINICOPATHOLOGICAL ENTITY

Aims.-The main clinicomorphologic findings from two new cases of intra ductal papillary-mucinous neoplasm of the pancreas were analyzed and d iscussed. Methods.-Formalin-fixed pancreatic tissues from the more rep resentative areas were routinely stained. An electron microscopic exam ination was performed in case 2 on glutaraldehyde-fixed tissue fragmen ts. Results.-Both patients had a long history of symptoms that was sug gestive of chronic pancreatitis. At endoscopic retrograde pancreatogra phy a dilatation of the main duct was observed. Ultrasonography reveal ed cystic dilatations that were interpreted as pseudocysts. The patien ts underwent total pancreatectomy. The gross appearance showed no mass , but the pancreas was enlarged and diffusely hard. The cut surface sh owed micromacrocysts filled with soft friable tissue and mucus. Histol ogical examination revealed diffuse neoplastic papillary proliferation s within ectatic and cystically dilated ducts. The lesions exhibited v arying grades of atypia and foci of in situ carcinoma. No clear eviden ce of invasion or lymph node metastases were observed. The nontumorous pancreas showed diffuse and multiple hyperplastic papillary changes i n the ductal tree. Conclusion.-The main clinicopathologic findings of intraductal papillary-mucinous neoplasm of the pancreas have been repo rted. Our study favors the hypothesis that chronic pancreatitis and/or ductal epithelial papillary hyperplasia may play a role in the pathog enesis of this tumor. We have emphasized the cystic appearance and muc inous features of this neoplasm, and so we suggest the use of the term intraductal papillary-mucinous neoplasm.