The Gastrointestinal Pathology Study

Background: Mucin producing cystic neoplasms, such as mucinous cystic tumor (MCT) and intraductal papillary mucinous tumor (IPMT) of the pancreas, are uncommon but become increas-ing in their incidences. The pathologic classification and biologic potential of these neoplasms remain the subject of controversy. Methods: The Gastrointestinal Pathology Study Group of the Korean Society of Pathologists analyzed the clinicopathologic characteristics of 85 cases of 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 pan-creatic duct (MPD, 68.1%), no ovarian-like stroma (0/72), and presence of intervening intra-tumoral normal or atrophic parenchyma. On the other hand, MCT was located largely in the tail (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 were significantly increased from adenoma through borderline to carcinoma, but MUC 1 was expressed only in the invasive carcinoma among cases of MCT and IPMT. Conclusions: The tumor location, ovarian-like stroma, connection with the MPD and intratumoral intervening nonneo-plastic tissue were helpful in the differential diagnosis between IPMT and MCT. CEA and p53 expressions can be indicators of malignancy, while MUC 1 expression can indicate invasion