CD117 Is a Specific Marker of Intraductal Papillary Mucinous Neoplasms (IPMN) of the Pancreas, Oncocytic Subtype.

Paola Mattiolo,Gaetano Paolino,Giovanni Marchegiani,Seung-Mo Hong,Claudia Parolini,Borislav C Rusev,Aldo Scarpa,Claudio Luchini,Paola Capelli,Paola Piccoli,Stefano Andrianello,Rita T Lawlor,Roberto Salvia

doi:10.3390/ijms21165794

Abstract

The intraductal oncocytic papillary neoplasm (IOPN) of the pancreas has been recognized by WHO classification as a unique intraductal papillary mucinous neoplasm (IPMN) category. IOPN is composed of oxyphil cells, usually expressing MUC5AC, MUC6, and Hep Par-1, and harboring PRKACA/B fusion genes as their genetic hallmark. Although IOPNs are associated with an infiltrative adenocarcinoma in up to 30% of cases, the survival rate after surgical resection approaches 100%. This highlights the importance of the correct IOPN diagnosis, above all in cases with an associated invasive component. In this study, the immunohistochemical expression of CD117 was investigated in 111 IPMNs, including 17 oncocytic, 45 gastric, 20 pancreatico-biliary, and 29 intestinal IPMNs. We also tested the expression of MUC5AC, MUC6, and Hep Par-1 in the IOPN cohort. CD117 positivity was significantly more frequent in IOPNs compared to the other IPMN subtypes (p < 0.0001). Furthermore, within IOPN, a lower or absent CD117, MUC5AC, MUC6, and Hep Par-1 expression tended to be associated with the presence of an infiltrative component. Our findings shed light into the biology of these complex lesions, which are confirmed to be a distinctive IPMN subtype; notably, CD117 emerged as a potential, additional tool in the differential diagnosis of IPMNs.

Highlights

The oncocytic subtype of intraductal papillary mucinous neoplasm, named intraductal oncocytic papillary neoplasm (IOPN), of the pancreas has been recognized by the currentWHO classification as a unique category of pancreatic IPMN [1]
We tested the immunohistochemical expression of CD117 in 17 pancreatic IOPNs and in 94 cases of different pancreatic IPMN subtypes, including 45 gastric, 20 pancreatico-biliary, and 29 intestinal type IPMNs
Our data clearly indicated that CD117 was expressed more frequently and with more diffuse/stronger staining patterns in IOPNs compared to the other IPMN subtypes [1,2,3]

Summary

Introduction

WHO classification as a unique category of pancreatic IPMN [1] It is a cystic epithelial neoplasm composed of exophytic nodular projections lined by oncocytic glandular epithelium, growing inside a dilated pancreatic ductal tree [1,2,3,4,5,6]. IOPNs represent about 5% of all intraductal neoplasms of the pancreas and are characterized by peculiar epidemiology and pathological features. They are more frequently discovered in males in their seventh decade of life and usually involve the main pancreatic duct [7,8,9]. IOPNs typically show high-grade dysplasia, and an associated carcinoma is found in up to 30% of cases [1,3,4]

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