Nucleolar organiser regions of mesothelial and carcinomatous cells in effusions.

The AgNor reaction was performed on effusions and peritoneal washings, and the silver dots were counted on normal or reactive mesothelial cells vs. carcinomatous cells, ascertained by previous HE staining. The mean values were 1.64 for the former (n = 20) and 4.90 for the latter (n = 10). The intersection between the two group distributions was 2.78, leaving a chance of only 0.65% for a false-positive result. The method may thus be helpful in the interpretation of doubtful cytological cases.