Nucleolar organizer region associated proteins in benign and malignant cutaneous melanocytic lesions.

This article reports that the histopathological assessment of malignancy may be difficult in certain melanocytic lesions. It has been shown that the number of demonstrable nucleolar organizer regions (NORs) may refiect the degree of histological malignancy. NORs are portions of ribosomal DNA present in the nucleoli. NORs and NOR-associated proteins may be stained by an agyrophilic technique and visualized as nuclear black granules. Benign melanocytic naevi had the fewest nucleolar organizer regions.