Assessment of nucleolar organizer regions (NORs) in proliferative conditions of the liver

To overcome the diagnostic dilemma in proliferative conditions of the liver which sometimes pose a problem to the working pathologist especially when the material is inadequate, a special staining technique (AgNOR) has been a pplied. By using this technique, nucleolar organizer regions were counted w hich determine the proliferative status of the cells. This prospective stud y included 65 cases of randomly selected liver core and fine needle aspirat ion biopsies. AgNOR staining was performed on formalin-fixed, paraffin-embe dded tissue sections NOR dots were counted in 100 randomly selected hepatoc ytes at x100 oil immersion objective, and the mean count per cell was calcu lated for each case. Statistical analysis was done by using the Mann Whitne y U test. AgNOR count results were later compared with the histologic diagn osis. The study revealed a gradual increase in mean AgNOR counts from norma l liver through cirrhosis to hepatocellular carcinoma. The difference in NO R counts was significant in these three groups. The hepatocellular carcinom as were graded according to the Edmondson-Steiner histological grading syst em. The Grade I hepatocellular carcinomas show AgNOR counts ranging between 5-6/cell, a score which is much higher than in the normal liver, where it ranges between 1.2-2.0/cell. This technique can be used to assess the lesio ns where the distinction between normal liver and Grade I hepatocellular ca rcinoma is difficult with the use of routine methods. AgNOR counts in norma l liver and chronic hepatitis cases were insignificant, but there was an ap preciable difference between cases of chronic hepatitis, cirrhosis and hepa tocellular carcinoma. In view of the results of this study, the AgNOR stain ing method is found to be a useful diagnostic tool to differentiate between normal liver, cirrhosis and hepatocellular carcinoma and also to precisely discriminate between cases of normal liver and Grade I hepatocellular carc inoma.