A20. Precancerous lesions and intraepidermal carcinoma

  • Precancerous lesions
    • Lentigo maligna
    • Actinic keratosis
      • Cutaneous horns
    • Leucoplakia
  • Intraepidermal carcinoma/carcinoma in situ
    • Bowen disease
    • Erythroplasia of Queyrat
    • Paget disease

Lentigo maligna

  • Precancerous lesion of dysplastic melanocytes
  • Occurs in elderly
  • Risk factor: UV exposure
  • Darkly pigmented macule
    • On sun-exposed areas
      • Face, neck
    • Irregular borders
    • 1 mm – 2 cm
    • Irregular colour
  • Treatment
    • Surgical excision with safety margin

Actinic keratosis

  • Precancerous lesions of squamous cells
  • Occurs in elderly with light skin
  • Risk factor: UV exposure
  • Clinical features
    • Small lesion with rough surface
    • -> lesion grows and becomes erythematous and scaly
    • On sun-exposed areas
    • May develop into a cutaneous horn
  • Treatment
    • Few lesions
      • Cryotherapy
    • Many lesions
      • 5-FU
      • Imiquimod
    • Prevention with sunscreen

Leucoplakia

  • Hyperkeratosis and dysplasia of epithelium and mucous membranes
  • Risk factors
    • Smoking
    • Alcohol
  • Clinical features
    • White plaque that cannot be scraped off
    • Most commonly in oral cavity
  • Differential diagnosis
    • Oral candidiasis
    • Oral hairy leukoplakia
  • Treatment
    • Avoidance of risk factors
    • Cryotherapy

Bowen disease

  • Squamous cell carcinoma in situ of skin
  • Risk factors
    • UV exposure
    • HPV 16, 18
    • Arsenic
  • Clinical features
    • Erythematous and scaly lesion
    • Irregular shape, sharp borders
    • On sun-exposed areas
  • Treatment
    • 5-FU
    • Imiquimod

Erythroplasia of Queyrat

  • Erythroplasia of Queyrat = Bowen disease of glans penis
  • Squamous cell carcinoma in situ of penile mucosa
  • Risk factors
    • Chronic inflammation
    • HPV 16, 18
  • Clinical features
    • Sharply demarcated, non-healing plaques or papules
    • May ulcerate or bleed
  • Treatment
    • 5-FU
    • Imiquimod

Paget disease of the breast

  • Ductal carcinoma in situ of the nipple and areola
  • Clinical features
    • Erythematous, scaly, vesicular rash
    • Pruritus
    • Burning
  • Treatment
    • Surgical removal