Immunohistochemical examinations in malignant melanoma: Fundamentals and special aspects

Immunohistochemical examinations have been used for many years in dermatopathology and pathology and have become an integral part of tumor diagnostics. The aim is to identify and classify tumor cells that express distinct antigens. Malignant melanoma can be characterized by a large number of well-described and standardized antibodies, so that immunohistochemical staining is used in the diagnosis of melanoma, the differential diagnosis of other tumors, the determination of tumor thickness, the diagnosis of tumor metastases, and also in the diagnosis of sentinel lymph nodes. Comprehensive knowledge of the expression profiles and specific staining patterns of the antibodies used is of great diagnostic relevance, with the aim of preventing misdiagnosis. The perfect antibody with high sensitivity and maximum specificity does not exist. Hence, immunohistochemistry does not replace the conventional assessment and interpretation of tumor samples. Only in symbiosis with clinical and conventional histological findings do immunohistochemical stains have a diagnostic value.