[1628] Gallbladder Intramural Papillary Mucinous Neoplasm: A New Entity Similar to IPMN of the Pancreas

K Nagata, GY Lauwers, S Murata, M Shimizu. Saitama Medical University, Saitama International Medical Center, Hidaka, Saitama, Japan; Massachusetts General Hospital, Boston, MA

Background: Intraductal papillary mucinous neoplasms (IPMNs) are classified as one of the pancreatic neoplasms, and recently similar neoplasms have been recognized in the bile duct. These neoplasms show characteristic mucin production, papillary projective growth, and some cyst formation. They have a good prognosis. Pancreatic intraepithelial neoplasia (PanIN) and biliary intraepithelial neoplasia (BilIN) are proposed as a precursor lesion of IPMNs and cholangiocarcinoma, respectively. In the gallbladder, sporadic case reports of these IPMN-like mucin-producing papillary neoplastic lesions are reported, however; no report that examined a series of a preceding lesion, a borderline lesion, or in situ carcinoma has been published. We name these lesions "gallbladder intramural papillary mucinous neoplasm (GB-IPMN)", and examined the mucin expression profiles of the series of hyperplasia/neoplasia, borderline lesion, and carcinoma in situ.
Design: We collected nine suitable cases for this study (three intraepithelial neoplasias, three borderline lesions, and three in situ carcinomas) from the Department of Pathology, Saitama Medical University, Saitama International Medical Center, and Massachusetts General Hospital from 2000 to 2008. The histological classification was made based on the criteria of pancreatic IPMN. One case of intraepithelial neoplasia associated with common tubular adenocarcinoma was also examined. All specimens were fixed in 10% formalin, embedded in paraffin wax, and cut into 4-micrometer-thick serial sections for usual hematoxylin and eosin staining and immunohistochemical staining. Immunohistochemically, MUC1, MUC2, MUC5AC, MUC6, CD10, p53 and MIB-1 were performed.
Results: Characteristically, the series of all intraepithelial neoplasia, borderline lesions, and carcinoma in situ were positive for MUC5AC and MUC6, and were negative for CD10. CD10 was performed by down regulation for the early phase of these neoplastic changes and showed a change which was similar to the PanIN results (Nagata et.al. J Hepatobiliary Pancreat Surg. 2007;14:243-54).
Conclusions: GB-IPMN and its precursor lesions have the same immunohistochemical mucin profiles as PanIN and IPMN of the pancreas. Further study is needed to clarify the significance of these lesions. In addition, a common type of gallbladder cancer derived from GB-IPMN should also be investigated.
Category: Liver & Pancreas

Tuesday, March 23, 2010 1:00 PM

Poster Session IV # 197, Tuesday Afternoon

 

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