Oral Melanoma

§ overviewOverview

Malignant neoplasm of melanocytes arising from oral mucosa, most commonly on palate or gingiva.

§ icdICD Classification

C03.9 / C05.0

§ etiologyEtiology

• 01Unknown; no UV association unlike cutaneous melanoma
• 02Possible role of chronic irritation, melanosis

§ epidemiologyEpidemiology

Rare (<1% of oral malignancies). Higher incidence in Japanese and Africans. Peak 5th–7th decade. M = F.

§ pathogenesisPathogenesis

Malignant transformation of mucosal melanocytes → radial then vertical growth.

§ clinicalClinical Features

• 01Brown-black macule/nodule
• 02Irregular borders, variegated colour
• 03May be amelanotic (pink/red)
• 04Palate and maxillary gingiva most common
• 05Late: ulceration, satellite lesions, bone invasion

§ differentialDifferential Diagnosis

• 01Melanotic macule
• 02Oral nevus
• 03Amalgam tattoo
• 04Kaposi sarcoma
• 05Pigmented SCC

§ histopathHistopathology

• 01Atypical melanocytes at junction and invasive
• 02High mitotic index
• 03Pleomorphism
• 04IHC: S-100, HMB-45, Melan-A positive

§ ihcIHC / Special Stains

• 01S-100 (sensitive)
• 02HMB-45, Melan-A (specific)
• 03SOX10

§ stagingStaging

AJCC mucosal melanoma staging (T3/T4 by definition)

§ treatmentTreatment

• 01Wide surgical excision (margins 1–2 cm when possible)
• 02Neck dissection if nodal disease
• 03Adjuvant immunotherapy (pembrolizumab, nivolumab)
• 04Radiotherapy (adjuvant/palliative)

§ prognosisPrognosis

Poor; 5-year survival 15–25%. Late presentation and rich lymphatics contribute.

§ examKey Examination Points

• 01Palate/maxillary gingiva
• 02ABCDE criteria modified for mucosa
• 03IHC: S-100, HMB-45

§ revisionQuick Revision Summary

• 01Poor prognosis unlike cutaneous
• 02Palate most common site
• 03Wide excision + immunotherapy

§ vivaBDS Viva Questions

• 01What is the prognosis of oral melanoma?
• 02How does it differ from cutaneous melanoma?
• 03Describe the immunohistochemistry.

§ mcqsMCQs — Assessment (3)

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