July 12, 2023

EDUCATIONAL PEARL

Head and Neck Melanoma: Malignant cancer of melanocytes

Presenting Symptoms: 

• ABCDE
  A: Asymmetry
  B: Irregular borders
  C: Color changes (red, blue, white spots in brown/black patches)
  D: Diameter > 6 mm
  E: Evolving 

• “Ugly Duckling” sign: Nevus evidently different than other surrounding nevi 

• Most common head and neck sites: occipital scalp and skin of cheek

• Risk factors: 

  • UV-B exposure

  • Severe sunburns in childhood

  • Pale skin (blue-green eyes)

  • Immunosuppression

  • Familial dysplastic nevus syndrome 

  • Previous melanoma

• Histopathology: Melanocyte cells that are neural crest in origin (S-100 positive)

  • Types of melanomas include: 

    • Superficial spreading: Most common; 70% from preexisting junctional nevi; horizontal phase transitions to vertical phase (ulceration);

    • Nodular: Most aggressive; may present on non sun-exposed skin; worst prognosis

    • Lentigo Maligna Melanoma: Arises from lentigo maligna (melanoma in-situ from proliferation of melanocytes in basalis layer) in sun-exposed skin; common in the elderly; common on head and neck; confined to epidermis

    • Acral Lentiginous: Found on soles of feet or hands, more common in darker skin tones

    • Mucosal melanoma: Found in mucosa instead of skin; poor prognosis; <10% of head and neck melanomas

    • Amelanotic: Poor prognosis 

    • Desmoplastic

  • Depth Classification: Breslow Thickness

    • Depth of invasion in mm

    • < 1 mm = thin melanoma

    • > 1 mm usually requires sentinel lymph node biopsy

• Diagnosis: Excisional biopsy with > 2 mm margins (never shave biopsy)

Management: 

• Prevent excess sun exposure

• Excision 

  • <1 mm depth: 1 cm margins

  • 1-2 mm depth: >1 cm margins

  • > 2 mm depth: 2 cm margins

  • Face: Resect to level of muscles of expression

  • Parotid: Resect to masseteric fascia

  • Scalp: Resect to calvarial periosteum

  • Auricle: Partial or total auriculectomy 

  • EAC: Possible temporal bone resection

• Sentinel Node Biopsy

  • Replaced elective neck dissection

  • Neck dissection reserved for positive nodes

  • Predictive of overall and disease-free survival

• Chemo/Immuno/Molecular therapy

• Radiation: typically reserved for non-surgical and palliative patients