Application of the AgNOR method to cell imprints of lymphoid tissue

The argyrophil (AgNOR) staining technique for nucleolar organizer regions was applied to both cell imprint preparations and 3 microns sections of 40 specimens of lymphoid tissue (10 normal tonsil, 10 reactive follicular hyperplasia, and 10 low-grade and 10 high-grade non-Hodgkin's lymphomas). The mean AgNOR count per nucleus was higher for imprint preparations than for 3 microns sections for each group of specimens (P less than 0.01). The difference was particularly evident for specimens with high AgNOR counts, that is, the high-grade non-Hodgkin's lymphomas (pooled mean AgNOR count/cell 16.3 for imprints as opposed to 6.0 for 3 microns sections, P less than 0.0001). Furthermore, individual AgNOR dots were much more readily discerned in cell imprints than in sections, and this appears to be the method of choice if pathologists wish to at least approach absolute rather than relative AgNOR counts.