Oral Melanoma



Oral Melanoma


Lester D. R. Thompson, MD










Primary melanoma of the hard palate presents as a diffuse, patchy area of heavy pigmentation with irregular borders image. Satellite lesions are noted away from the main area of pigmentation image.






High magnification shows mucosal lentiginous melanoma of the hard palate with numerous atypical melanocytes present in the basal epithelium image and invasion into the superficial submucosa image.


TERMINOLOGY


Definitions



  • Malignant neural crest-derived neoplasm with melanocytic differentiation



    • Atypical melanocytes at epithelial-connective tissue interface with upward migration or connective tissue invasion


ETIOLOGY/PATHOGENESIS


Etiology



  • Unknown (no ultraviolet exposure)


CLINICAL ISSUES


Epidemiology



  • Incidence



    • Extremely rare, accounting for < 1% of all melanomas



      • 0.02/100,000 population/year in USA


    • Represent about 50% of all head and neck mucosal melanomas


    • Represent < 0.5% of all oral malignancies


    • Unlike cutaneous melanoma, oral melanoma incidence has been stable


  • Age



    • Mean in 6th-7th decades


    • Rare in pediatric age group


  • Gender



    • Male > female (2.5-3:1)


  • Ethnicity



    • More common in Japan and western Africa


Site



  • Hard palate and maxillary alveolus are most common sites of involvement (˜ 80%)


  • Remaining 20% include



    • Mandibular gingivae


    • Buccal mucosa


    • Floor of mouth and tongue


Presentation



  • Most arise de novo although 1/3 are preceded by pigmented lesion for a few months or years



    • “Melanosis” reported before development of melanoma


  • Asymmetric, painless, pigmented lesion



    • Irregular borders or outlines


    • Black, purple, red, gray



      • 15% of oral melanomas are amelanotic


    • Macular, with nodular areas


  • Many patients present at advanced stage with pain, ulceration, loose teeth


  • Cervical lymph nodes mets reported in up to 75% of cases at presentation


  • Distant metastases present in about 50% at presentation


Treatment

Jul 8, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Oral Melanoma
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