Update on eighth edition American Joint Committee on Cancer classification for cutaneous melanoma and overview of potential pitfalls in histological examination of staging parameters

Cutaneous melanoma causes most of the skin cancer deaths in the USA. Melanoma is the fifth most common cancer among men and the sixth most common cancer among women. The incidence of melanoma has risen sharply over the past three decades. In this review, which is informed by our extensive experience at a large cancer centre, we outline the key differences between the tumour, node and metastases staging criteria for cutaneous melanoma in the seventh and eighth editions of the AJCC Cancer Staging Manual. We also offer advice on how to assess the histophenotypic parameters that are relevant for staging, with a special focus on avoiding potential pitfalls, and how to report all the prognostically and therapeutically relevant histophenotypic parameters. Correct assessment and reporting of these clinically relevant histophenotypic parameters is of outmost importance for practising pathologists because these parameters help treating clinicians select the most appropriate personalised treatment for patients in this era of promising targeted and immunotherapies.