Prognosing melanomas: the argyrophilic nucleolar organizer region approach.

Staining of argyrophilic nucleolar organizer regions (AgNORs) is a histological technique that has been assayed on a vast array of cutaneous tumors in order to help distinguish benign from malignant lesions. In a number of papers, malignant melanomas have been found to have a higher number of black nucleolar and extranucleolar dots (i.e. AgNORs) than benign nevi, including Spitz nevus. The technique may be used for prognostic purposes, as a recent paper suggests. Melanomas with more than 3.62 AgNORs/cell have a higher probability to develop metastasis than melanomas with fewer AgNORs. The problems such an apparently simple, fast and reproducible technique may pose are discussed in detail.