Pathology of malignant tumours of the skin

The skin gives rise to a diverse spectrum of malignant tumours derived from the varied constituents of the epidermis and dermis. It is possible to discuss only a few of these in this article; the more common lesions derived from the epidermal keratinoctyes (basal and squamous cell carcinomas) together with melanomas (derived mainly from epidermal melanocytes) are presented. Some rarer but biologically aggressive tumours such as Merkel cell carcinoma and angiosarcoma are also discussed. Our understanding of the molecular biology of cutaneous tumours continues to evolve rapidly particularly for melanomas and in the coming years genetic profiling of individual tumours with targeted therapy is likely to play an important role in management.