Demonstration of nucleolar organizer regions in intrahepatic bile duct carcinoma by the silver-staining technique.

A silver colloid technique to identify argyrophilic nucleolar organizer region associated protein (AgNOR) was applied to 43 cases of intrahepatic bile duct carcinoma (cholangiocarcinoma, CC), 2 with bile duct adenoma (BDA), 5 with focal duct epithelial hyperplasia (FEH) associated with hepatolithiasis, 15 with posthepatitic ductular proliferation (PHDP) associated with massive or submassive hepatic necrosis and 20 of normal liver. In the present study, only discrete, easily counted black dots within nuclei and silver-stained nucleolus were counted under a magnification of x 400 without oil-immersion objectives. The mean AgNOR count of CC was significantly higher than those of BDA, FEH, PHDP and normal controls (P less than 0.05, P less than 0.001, P less than 0.01, and P less than 0.001, respectively). Among CCs the mean AgNOR numbers of papillary adenocarcinoma (pap), moderately (tub2) and poorly differentiated (por) adenocarcinoma, and adenosquamous carcinoma (as) were significantly higher than that of normal controls (P less than 0.01, P less than 0.001, P less than 0.001 and P less than 0.001, respectively), and those of tub2, por and as were also significantly higher than those of BDA, FEH and PHDP, whereas that of well differentiated tubular adenocarcinoma (tub1) was not different from those of BDA, FEH, PHDP and normal controls, and that of pap was not different from those of BDA, FEH and PHDP. The mean numbers of AgNORs of BDA and FEH were not different from that of normal controls, whereas that of PHDP was significantly higher than that of normal controls (P less than 0.01). Interestingly, the mean AgNOR counts of tubular adenocarcinoma were increased with histologic tumor grades.(ABSTRACT TRUNCATED AT 250 WORDS)