What does the 4th edition of the World Health Organization Classification of Head and Neck Tumors (2017) bring new about mucosal melanomas?

Abstract

The recently published 4th Edition of the World Health Organization Classification of Head and Neck Tumors addresses the most relevant and updated aspects of tumor biology, including clinical presentation, histopathology, immunohistochemistry, and prognosis of head and neck tumors. The objective of the present study is to compare these updates to the 3rd edition of that book with regard to mucosal melanomas and to highlight the potential factors that differ those tumors from cutaneous melanomas. We observed progress in the understanding of oral and sinonasal mucosal melanomas, which also present themselves, in the molecular scope, differently form cutaneous melanomas.

Primary melanoma of the oral cavity: A multi-institutional retrospective analysis in Brazil

“…The etiology of OMs remain unknown and seems to be different from CMs due to the lack of relation with risk factors, such as family history, association with atypical nevi, and exposure to ultraviolet radiation, conditions favoring the onset of melanoma of skin ( 3 , 8 , 9 ). Additionally, smoking has been suggested as a risk factor for OM because it is known that pigmented oral lesions are more prevalent among smokers.…”

“…Factors associated with a worse prognosis include tumor polymorphism, vascular invasion, advanced age, positive surgical margins, deep infiltration, and necrosis ( 6 , 8 ). Classical parameters to the prognosis of CM, such as Clark's level and Breslow's depth, have limited application to mucosal melanomas, maybe because most tumors are more profound than 4mm when diagnosed.…”

“…It is believed that OM originates from the malignant transformation of melanocytic cells present in the oral mucosa epithelium ( 5 , 6 ). There are no etiological factors associated with the development of OM; however, an association with BRAF, RAS, KIT, and BAP1 mutations have been described ( 7 , 8 ).…”

Melanoma oral metastático: tratamento com radioterapia e nivolumabe

“…Melanoma has an asymptomatic onset, difficult visualization, and few clinical signs 1,9,14 . The initial symptom of melanoma is usually a dark macule and edema that progresses to an ulcer on the hard palate 7,15 .…”

“…As the disease progresses, symptoms may include pain, tumor, ulcers and bleeding. Metastasis is also common, which partially explains the high mortality rates and the frequent late diagnosis 6,7,14,16 .…”