Cytodiagnostic Studies Of Malignant Tumors

Abstract

This study dealt with cytodiagnosis of malignant. tumors through light microscopic examination, counting of NORs using silver staining technique and . scanning electron microscopy. Nucleolar organizer regions (NORs) are loops ofDNA that are responsible for ribosomal RNA (rRNA) transcription. The number of NORs in each cell nucleus reflects its activity. NORs can be identified in paraffin embedded tissues or cytological preparations by the one step silver staining technique. In this study, 200 cases were examined; 85 cases of pleural effusion, 31 cases of peritoneal effusion and 84 cases of retroperitoneal masses which were obtained by U.S.-FNAB. The Ag-NORs dots were counted randomly in 30 cells in eah case by the use of oil immersion lens (X 1000). The numbers of Ag-NORs dots were tabulated and the mean Ag-NORs count for each case was calculated. The results were statistically tested.

The qualitative evaluation of Ag-NORs regarding size, shape, distribution and contour is as important as the quantitative evaluation. The pattern of Ag-NORs in malignant lesions was different from that pattern in reactive lesions, this is related to difference in cellular proliferation and presence of cells in different stages of cell cycle. The Ag-nucleoli were smaller in benign cells with homogenous staining and

some of them had dots that can be counted easily but in malignant cells, they were larger, bizzare in shape with areas of denser staining and the clumps within the aggregates could not be counted easily. Silver nucleolar organizer regions staining technique is easily performed, cheap, rapid and provides helpful results in some situations, but each centre must assess its own parameters according to its methodology. In this study, the Ag-NORs count in non-Hodgkin's lymphoma cases ranged from 4.5-12.2 Ag-NORs/cell (mean 8.1); Ag-NORs count in adenocarcinoma cases was 7.7-15.8 Ag-NORs/cell (mean 10.7); Ag-NORs count in squamous cell care.,