Melanoma of the oral cavity: pathogenesis, dermoscopy, clinical features, staging and management

Abstract

Primary mucosal melanoma of the oral cavity is an exceedingly rare neoplasm which is estimated to comprise 1-2% of all oral malignancies. In contrast to cutaneous melanomas, the risk factors and pathogenesis are poorly understood. The predominate localization of primary oral melanoma is hard palate and maxillary alveolus. Dermoscopy may be utilized as an adjunctive tool in the clinical differential diagnosis of oral mucosal melanoma whenever the lesion is accessible with a dermoscope. Surgery is the mainstay of treatment, but it may be challenging depending on the location of the tumor within the oral cavity and its size. Adjuvant therapy with dacarbazine, platinum analogs, nitrosoureas and interleukin-2 have been utilized with low response rates. Imatinib may be effective for patients with with c-Kit gene mutations. Sunitinib and dasatinib have been reported effective in selected cases. Vemurafenib and dabrafenib are targeted agents for patients with BRAF mutation-positive melanoma. Ipilimumab, an anti-cytotoxic T-lymphocyte antigen 4 antibody and pembrolizumab, a monoclonal antibody targeting programmed death 1 receptor may be a feasible treatment option in patients with metastatic mucosal melanoma. (J Dermatol Case Rep. 2014; 8(3) Melanoma is a malignant tumor that arises from melanocytes and is most commonly cutaneous in origin. Extracutaneous melanomas are known to be exceedingly rare and aggressive neoplasms that embrace ocular, mucosal and leptomeningeal melanomas. EpidemiologyMucosal melanomas are estimated to comprise 4-6.8 % of all primary melanomas. 1The incidence rate for mucosal melanoma (MM) is 2.3 per million. 1,2The incidence of MM increases with age. Older patients have tenfold higher incidence of MM compared to patients under the age of 60 years. 2Primary oral mucosal melanoma (POMM) is excessively uncommon in prepubertal children. 3Although there is a slight male preponderance (1.2:1), 1,4 some studies have been reported higher gender distribution of mucosal melanoma for women, 5,6 other indicate that there is no significant difference between sexes in the incidence of this tumor. 2,7The incidence rate of POMM is highest among Asian men. 3,6 Among the Japanese oral melanoma accounts for 7.5 % of all melanomas versus less than 1 % in Caucasians. 8,9Pathogenesis In contrast to cutaneous melanomas, the etiology and pathogenesis of POMM is poorly understood and no etiological and intraoral risk factors, other than preexisting pigmented nevi, have been identified. 10,11 POMM are believed to arise from pigmented nevi, pre-existing pigmented areas or de novo (30% cases) from apparently normal mucosa. 9,12 Although Kahn et al 13 described transformation of a benign oral pigmentation to primary oral melanoma, a definite precursor lesion has not been identified. 14,15 In the oral cavity, mechanical trauma including injury from ill-fitting prostheses, infection, tobacco use has been cited as possible causative factors, but its etiological role seems unlikely. 30Amelanotic oral melanoma is partic...

Gingival Leiomyosarcoma in a Young Woman: Case report and literature review

“…10 Other malignancies with spindle cell morphology include squamous cell carcinomas, gastrointestinal stromal tumours, fibrosarcomas, myofibroblastic sarcomas, melanomas, rhabdomyosarcomas and spindle cell myoepithelial carcinomas. [11][12][13][14][15][16][17] In particular, myofibroblastic sarcomas and rhabdomyosarcomas also affect younger individuals, proteins. The final diagnosis was of a well-differentiated grade I LMS.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Besides early diagnosis, the prognosis of oral LMS patients depends on the tumour grade, size, site and treatment. [20][21][22] Currently, there are no standard criteria for therapy, although the complete excision of the tumour with wide surgical margins is recommended.…”

Comparative study of head and neck mucosal melanoma in 66 patients vs 226 patients with cutaneous melanoma: A survival analysis

“…Treatment of choice for MM and CM is wide resection. However, it is not always possible to obtain adequate margins, especially in the head and neck . Regional involvement presents in between 10% and 30% of cases.…”

Oral Mucosa Malignant Melanoma: Clinical Features, Diagnosis, Treatment, and a Case Report

“…However, melanoma metastasis may also involve the epithelial junction, however the presence of junctional activity is not reliable to indicate the lesion as a primary one. Dermoscopy may be utilized as an adjunctive tool in clinical differential diagnosis of oral mucosal melanoma, which allows easy differentiation of amalgam tattoos, "in situ" and invasive melanoma [3]. A flow-chart for the diagnosis of pigmented lesions in the oral mucosa and perioral tissues was suggested by Meleti et al [12], which could excludes or includes melanoma by the following questions and examination step by step: medical history, melanotic or non-melanotic lesions, ABCD checklist, recent history, age and subsite.…”

“…They are usually larger than normal melanocytes and have varying degrees of nuclear pleomorphism and hyperchromatism. In oral lesions, invasion of lymphatic and blood vessels are seen more readily than skin lesions [3]. Several A 70-year-old male was referred to our department due to a painless but easily bleeding mass over right upper posterior gingiva.…”