ABSTRACT
BACKGROUND: Mucin producing cystic neoplasms, such as mucinous cystic tumor (MCT) and intraductal papillary mucinous tumor (IPMT) of the pancreas, are uncommon but become increasing in their incidences. The pathologic classification and biologic potential of these neoplasmsremain the subject of controversy. METHODS: The Gastrointestinal Pathology Study Group of the Korean Society of Pathologists analyzed the clinicopathologic characteristics of 85 casesof MCT and 72 cases of IPMT and examined the expression patterns of p53, CEA and MUC1. RESULTS: IPMT was located largely in the head, and showed connection with the main pancreatic duct (MPD, 68.1%), no ovarian-like stroma (0/72), and presence of intervening intratumoralnormal or atrophic parenchyma. On the other hand, MCT was located largely in thetail (73%), and showed common ovarian-like stroma (66/80), rare connection with the MPD(7/85) and no intervening pancreatic parenchyma. CEA and p53 immunoexpressions weresignificantly increased from adenoma through borderline to carcinoma, but MUC 1 was expressedonly in the invasive carcinoma among cases of MCT and IPMT. CONCLUSIONS: The tumorlocation, ovarian-like stroma, connection with the MPD and intratumoral intervening nonneoplastictissue were helpful in the differential diagnosis between IPMT and MCT. CEA and p53expressions can be indicators of malignancy, while MUC 1 expression can indicate invasion.