Recent advances and important issues in melanoma pathology: an update for oncologists

The critical role of pathology in the multidisciplinary care of melanoma patients is becoming apparent in the rapidly changing modern era of personalised and precisely targeted medicine. Recent insights into the molecular pathogenesis of melanoma have allowed traditional pathological assessment to be supplemented and enhanced by molecular pathology testing to improve classification, prognostication and selection of patients for targeted therapies. The pathology report remains pivotal as it establishes the definitive diagnosis of melanoma in most instances, while the assessment and documentation of key pathological parameters allow the most accurate determination of prognosis to be made and are utilised to guide the next stages of patient management. Molecular tests (including fluorescent in situ hybridisation) are now routinely utilised to enhance the accuracy of classification and prognostication of selected melanocytic tumours in many institutions. Recent studies have also highlighted important melanoma prognosticators such as mitotic rate, the presence and extent of ulceration, tumour-infiltrating lymphocyte grade and sentinel lymph node biopsy. Pathologists also play a key role in the triage and selection of appropriate tumour tissue and tumour cells to test for various molecular markers which are used to select patients who may benefit from targeted therapies. It is important that clinicians understand important aspects of molecular testing in melanoma, such as when and how to arrange testing, which specimen to test, and the advantages and disadvantages of the various testing methodologies. These issues are addressed in this review. Pathology is a key component of the multidisciplinary care of melanoma patients. While melanoma may be suspected clinically, the initial definitive diagnosis is usually established by pathological examination of a tissue biopsy. In clinically localised primary cutaneous melanoma, pathological assessment of various tumour parameters enables accurate estimation of prognosis and determines the most appropriate next step(s) in clinical management. Pathological evaluation of any potential or likely metastasis is also critical. Recent discoveries of the molecular pathogenesis of melanoma are now being harnessed clinically to improve patient management. Molecular pathology is now utilised to enhance melanoma diagnosis, classification, prognostication and to predict responsiveness to selective targeted therapies in melanoma, and will undoubtedly play an ever-increasing role in the management of melanoma patients. In this article we review selected important issues in melanocytic