Diagnostic value of silver nitrate staining for nucleolar organizer regions in selected head and neck tumors

Background: The present study is aimed to assess the usefulness of silver nitrate staining of nucleolar organizer regions (NORs) as a quantitative criterion for the diagnosis of selected head and neck tumors.
Materials and Methods: The silver nitrate staining technique was used on 195 paraffin blocks collected from 85 patients. The samples consisted of 21 squamous cell carcinoma (SCC) of larynx, 28 SCC of oral mucosa and 36 samples of most common salivary gland tumors. Mann-Whitney U-Test was used for data analysis.
Results: A significant difference was seen in the number of AgNOR dots between oral and laryngeal SCC with surrounding dysplastic and normal tissues ( P < 0.001) and also between mucoepidermoid carcinoma and adenoid cystic carcinoma with pleomorphic adenoma and normal salivary gland tissue ( P < 0.001).
Conclusion: The silver nitrate staining for NORs is a useful method for aiding the diagnosis of malignant and dysplastic mucosal lesions and also malignant and benign salivary gland tumors.

Keywords
Laryngeal squamous cell carcinoma, malignancy, nucleolar organizer regions, oral squamous cell carcinoma, salivary gland tumors, silver nitrate staining