Histologic and immunohistochemical changes in the stented common bile duct.

Many patients with pancreatic carcinoma have stent placement for biliary obstruction before resection. Stent-associated atypia, found in common bile duct (CBD) margins at the time of resection, may be confused with malignancy. We evaluated histologic and immunohistochemical changes in CBD margins from resection specimens for pancreatic carcinoma. Histologic findings in CBDs, including ulcer and inflammation; epithelial metaplasia, atypia, and gland complexity; and increased wall thickness, nerve entrapment, and smooth muscle content, were compared in 30 stented and 31 nonstented CBD margins from pancreaticoduodenectomies for carcinoma and 13 normal CBDs from autopsy material. The proliferation index was calculated for stented and nonstented CBDs after Ki-67 immunohistochemical staining. Immunostaining for Ki-67, p53, and c-erbB-2 was performed in stented CBDs and corresponding carcinomas. All the histologic changes occurred more frequently in stented and nonstented CBD margins from carcinoma patients than in normal CBDs. Stented CBDs had significantly increased epithelial changes and Ki-67 proliferation rate as compared with nonstented CBDs. The stented CBDs had significantly less p53 and c-erbB-2 expression as compared with corresponding pancreatic carcinomas. Caution should be applied when interpreting atypia in CBD margins from patients with a history of CBD stenting. Changes found in stented CBDs are characteristic, and in most cases can be distinguished from malignancy. In difficult cases, immunohistochemistry may be useful.