Mucinous Cystic Neoplasms of the Gallbladder: A Clinicopathological and Immunohistochemical Study
Juan C Hernandez Prera, Jie Ouyang, Stephen Ward, Xuchen Zhang, Hongfa Zhu, Swan N Thung, M Isabel Fiel. The Mount Sinai Medical Center, New York, NY
Background: Mucinous cystic neoplasms (MCN) of the hepatobiliary tree are rare tumors, but even rarer are MCN arising from the gallbladder (GB). Most are lined by a single layer of either gastric or pancreatobiliary epithelium with ovarian-type stroma. This study aims to characterize the clinical, histological and immunohistochemical (IHC) profile of GB MCN and compare them with intrahepatic (IH) MCN.
Design: The pathology database from 1995-2011 was searched; clinical data was gathered from medical records. Histological assessment was performed; IHC using antibodies to CK7, CK19, MUC2, MUC5AC and MUC6 was performed. Immunoreactivity was scored: 0 negative; 1 focal; 2 <50% cells + staining; 3 >50% strong + staining. Clinicopathological features and mucin profile were compared with 12 previously studied IH MCN.
Results: Six GB MCN of 16,638 GB specimens were found (0.03%). Four of 6 were female, mean age 72 years (range 55-90). All were incidentally found during unrelated surgical procedures (3 resection for malignant hepatic tumors, 2 colectomy, 1 harvesting for cadaveric donation). Five of 6 (83%) were located in the fundus; 1 in the GB neck; 4/6 (67%) were of the multilocular type, and 2 with combined multilocular and papillary architecture. Size ranged from 0.9-5cm (ave 1.8cm). Pure pancreatobiliary lining epithelium was found in 4/6 and mixed gastric and pancreatobiliary in 2/6; ovarian type stroma was seen in all cases. No epithelial dysplasia or carcinoma was found. The pancreatobiliary-type epithelium had 3+ staining for CK7, CK19 and MUC6; MUC2 was 1+ in 3 (50%). All cases were reactive to MUC5AC but with variable staining (1+ in 4, 3+ in 2). The gastric foveolar epithelium in the two mixed cases was 3+ for MUC5AC and MUC6, and 1+ for MUC2. Table 1 compares GB and IH MCN at our institution.
|GB MCN||IH MCN|
|Epithelium||67% pancreatobiliary 33% mixed||33% pancreatobiliary 59% mixed 8% gastric|