Argyrophilic nucleolar organizer regions in soft tissue tumors

Argyrophilic nucleolar organizer region (AgNOR) staining was employed on 51 apparently normal representative soft tissues, 53 benign soft tissues tumors and 52 malignant soft tissue tumors with an aim to study the sensitivity and specificity of method in differentiating between the benign and malignant soft tissue tumors. The mean AgNORs count in apparently normal fibrous tissue was 1.02, whereas it was 0.94 in adipose tissue, 1.14 in smooth muscle tissue, 1.115 in skeletal muscle tissue, 1.025 in blood vessels endothelial lining cells and 1.04 in nerve tissue. The mean AgNOR count was found to be higher in benign soft tissue tumors as compared to respective apparently normal soft tissue and was found to be statistically significant. The mean AgNOR count in soft tissue sarcomas was found to be higher as compared to both apparently normal soft tissue and benign soft tissue tumors. An increase AgNOR score in both benign and malignant soft tissue tumors as compared to apparently normal soft tissue indicates high proliferative activity. The neurofibrosarcoma showed low AgNOR count as compared to other soft tissues sarcomas. The fibrohistiocytic sarcoma, leiomyosarcoma and angiosarcoma showed a mean AgNOR score of 4 or more than four. The mean AgNOR score was found to increase with high grade of the tumor. The AgNOR staining is simple and useful method in estimating tumor cell proliferation thereby differentiating normal soft tissue from non-neoplastic proliferative growth, benign and malignant soft tissue tumors. It may help in differentiating fibromatosis from fibrosarcoma, dermatofibrosarcoma protuberans of low grade malignancy from high grade malignant fibrous histiocytoma and benign hemangiopericytoma from malignant hemangiopericytoma.