Classification and Histopathology of Melanoma

While a melanoma may be suspected clinically, a definitive diagnosis usually requires pathologic assessment of a tissue biopsy. Pathologic diagnosis of melanoma requires evaluation of changes in the architectural and cytologic features and must be interpreted in the clinical context of the biopsy including the age of the patient and site of the lesion. The pathology report should document pathologic features important for guiding patient management, including those characteristics upon which the diagnosis was based and also prognostic factors. The traditional Clark-McGovern classification of melanoma has been validated to have molecular underpinning,and in the 2018 World Health Organization Classification of Skin Tumors, clinical, epidemiologic, pathologic, and molecular features have been integrated to define nine pathways of melanoma pathogenesis. Recent molecular studies have also opened new avenues for the treatment of patients with metastatic melanoma, and molecular pathology is likely to play an important role in the expanding field of personalized melanoma therapy.