Onkológia 3/2009

Diagnosis of melanoma

The worldwide documented increase of malignant melanoma´s incidence by over 4% per year stimulates an improvement of its diagnosis. The diagnosis includes traditionally known clinical approaches, recently supplemented by implementation of modern visualizing methods. In spite of the broad morphological heterogeneity of both primary and secondary melanoma, the histopathological evaluation still represents the gold standard of its biopsy diagnostics. Immunohistochemistry has been the primary specific tool to distinguish melanoma from tumours of non-melanocytic origin and to detect metastatic involvement of the lymph nodes. Although many „new“ markers of melanocytic origin are now available, S100 protein detection remains the most sensitive marker of melanocytic lesions. However, with the exception of usually higher proliferation activity in malignant lesions, the contribution of immunohistochemistry to the differencial diagnosis of benign versus malignant melanocytic tumors is limited. The fluorescence in-situ hybridization seems to become a new diagnostic method to discriminate between benign and malignant melanocytic lesions. It can be performed on formalin-fixed, paraffin-embedded tissue specimens and allows directly to correlate genomic alterations with morphological features.

Keywords: malignant melanoma, biopsy diagnosis, immunohistochemistry, FISH