On the facial skin, the malar region is a common site for melanoma because this area of the face is subject to significant solar exposure. In fact, cutaneous melanoma is most common among white populations that live in sunbelt regions of the world. Facial cutaneous melanomas may appear macular or nodular, and the coloration can be quite varied, ranging from brown to black to blue, with zones of depigmentation. An important difference is that unlike common nevi that exhibit smooth outlines, melanomas show jagged irregular margins. These lesions are more common among elderly
patients and show a male predilection. The term “lentigo maligna melanoma” or “Hutchinson’s freckle” has been applied to these facial skin lesions that exhibit atypical melanocytic hyperplasia or melanoma in situ. The melanocytic tumor cells spread laterally and therefore superficially; this pattern has been referred to as a radial growth phase. These lesions have a good prognosis if they are detected and treated before the appearance of nodular lesions, which indicates invasion into the deeper connective tissue (ie, a vertical growth phase). The level of invasion is determined by the Breslow method, by which millimeter depths of invasion are measured (depth correlating with prognosis).
Mucosal melanomas are extremely rare. Their prevalence appears to be higher among Japanese people than among other populations. Melanomas arising in the oral mucosa tend to occur on the anterior labial gingiva and the anterior aspect of the hard palate. In the early stages, oral melanomas are macular brown and black plaques with an irregular outline. They may be focal or diffuse and mosaic, and the differential diagnosis should include nevi, melanotic macules, and amalgam tattoo. Any pigmented oral lesion with an irregular margin or with a history of growth should be suspect, and a biopsy of it should be performed without delay. Eventually, melanomas become more diffuse, nodular, and tumefactive, with foci of hyper- and hypopigmentation.
Microscopically, oral mucosal melanomas (like cutaneous melanomas) may exhibit a radial or a vertical pattern of growth. The radial or superficial spreading pattern is seen in macular lesions; clusters and theques of nevus cells showing nuclear atypia and hyperchromatism proliferate within the basal cell junctional region of the epithelium, and many of the neoplastic cells invade the overlying epithelium as well as the submucosa. Once vertical growth into the connective tissue progresses, the lesions can become clinically tumefactive. The vertical growth phase connotes a poor prognosis because of the likelihood of lymphatic and hematogenous metastasis, and grading systems are based on the quantitation of vertical penetration of the submucosa. The Breslow classification has not been applied to oral melanomas, principally because they are generally quite advanced and invasive when biopsy specimens are initially obtained.
Excision with wide margins is the treatment of choice; once nodularity has evolved, however, the lesion has probably already metastasized. Computed tomography and magnetic resonance imaging studies should be undertaken to explore regional metastases to the submandibular and cervical lymph nodes. A variety of chemo- and immunotherapeutic strategies can be used once metastases have been identified.
Mucosal melanomas are extremely rare. Their prevalence appears to be higher among Japanese people than among other populations. Melanomas arising in the oral mucosa tend to occur on the anterior labial gingiva and the anterior aspect of the hard palate. In the early stages, oral melanomas are macular brown and black plaques with an irregular outline. They may be focal or diffuse and mosaic, and the differential diagnosis should include nevi, melanotic macules, and amalgam tattoo. Any pigmented oral lesion with an irregular margin or with a history of growth should be suspect, and a biopsy of it should be performed without delay. Eventually, melanomas become more diffuse, nodular, and tumefactive, with foci of hyper- and hypopigmentation.
Microscopically, oral mucosal melanomas (like cutaneous melanomas) may exhibit a radial or a vertical pattern of growth. The radial or superficial spreading pattern is seen in macular lesions; clusters and theques of nevus cells showing nuclear atypia and hyperchromatism proliferate within the basal cell junctional region of the epithelium, and many of the neoplastic cells invade the overlying epithelium as well as the submucosa. Once vertical growth into the connective tissue progresses, the lesions can become clinically tumefactive. The vertical growth phase connotes a poor prognosis because of the likelihood of lymphatic and hematogenous metastasis, and grading systems are based on the quantitation of vertical penetration of the submucosa. The Breslow classification has not been applied to oral melanomas, principally because they are generally quite advanced and invasive when biopsy specimens are initially obtained.
Excision with wide margins is the treatment of choice; once nodularity has evolved, however, the lesion has probably already metastasized. Computed tomography and magnetic resonance imaging studies should be undertaken to explore regional metastases to the submandibular and cervical lymph nodes. A variety of chemo- and immunotherapeutic strategies can be used once metastases have been identified.