AtlasPigmentedOral Melanoma

Pigmented Lesions

Oral Melanoma

aka Mucosal Melanoma · Primary Oral Melanoma

Rare, aggressive malignancy of melanocytes in oral mucosa with poor prognosis.

Site
Palate / maxillary gingiva
IHC
S-100, HMB-45, Melan-A
Prognosis
Poor (15-25% 5yr)

Red Flags

  • ·New or changing pigmented lesion
  • ·Irregular borders
  • ·Rapid growth
  • ·Ulceration

§ 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)

Question 1

Most common site for oral melanoma:

Question 2

IHC marker for melanoma:

Question 3

5-year survival for oral melanoma:

References

  1. Neville BW. Oral & Maxillofacial Pathology, 4e
  2. Hicks MJ. Oral Oncology 2002

Draft — pending faculty review. Educational use only; verify against current guidelines and primary sources before clinical application.