Comparison Between Mucinous Cystic Neoplasm and Intraductal Papillary Mucinous Neoplasm of the Branch Duct Type of the Pancreas With Respect to Expression of CD10 and Cytokeratin 20

Objective: Mucinous cystic neoplasm (MCN) and intraductal papillary mucinous neoplasm of the branch duct type (IPMN-BD) differ in biological and clinical behaviors, but MCN is often misdiagnosed as IPMN-BD. The purpose of this study was to find useful markers for the differential diagnosis of MCN and IPMN-BD. Methods: Immunohistochemically, the expression of the 2 types of mucin (MUC) 1 (MUC1/DF3 and MUC1/CORE), MUC2, MUC5AC, MUC6, human gastric mucin (HGM), caudal-related homeobox transcription factor 2 (CDX2), CD10, cytokeratin (CK) 7, and CK20 was examined in 7 cases of MCN and 16 cases of IPMN-BD. Results: Expression frequencies in MCN and IPMN-BD were 100% versus 44% for MUC1/DF3, 86% versus 31% for MUC1/CORE, 57% versus 19% for MUC2, 86% versus 100% for MUC5AC, 57% versus 88% for MUC6, 86% versus 100% for HGM, 57% versus 0% for CDX2, 71% versus 0% for CD10, 100% versus 69% for CK7, and 86% versus 6% for CK20. Conclusions: Mucin 1/DF3, MUC1/CORE, CDX2, CD10, and CK20 were expressed significantly more frequently in MCN than in IPMN-BD. In particular, CD10 and CK20 showed marked differences in immunohistochemical sensitivity and specificity between MCN and IPMN-BD. It is therefore proposed that CD10 and CK20 may be used for the differential diagnosis of MCN and IPMN-BD.