Precancerous skin lesions

Precancerous skin lesions refer to various dermatological growths that are at an increased risk of developing into skin cancer. Typical precancerous skin lesions include lentigo maligna, which may develop into malignant melanoma, and actinic keratosis, which may develop into squamous cell carcinoma. There is also a risk of leukoplakia – presenting in the oral cavity as white plaques – progressing to squamous cell carcinoma. Bowen disease and erythroplasia of Queyrat are less common types of precancerous skin lesions and are often associated with the human papillomavirus (HPV). To prevent malignant transformation, surgical excision is usually the treatment of choice.

Actinic keratosis and bowenoid papulosis are detailed separately.

• Definition: hyperkeratosis of the epithelium and mucous membranes ^[1][2][3]
• Etiology
  • Tobacco smoking
  • Alcohol consumption
• Lesion ^[4]
  • Most commonly affects the oral cavity
  • Persistent white plaques that usually cannot be scraped off
  • Homogeneous appearance: uniform texture, well-defined margins
  • Nonhomogeneous appearance (e.g., erythroleukoplakia) : Irregular texture, can be speckled, nodular, granular, and/or verrucous
• Diagnostics: All oral leukoplakia lesions must be biopsied to evaluate the grade of dysplasia and to exclude differential diagnoses. ^[5][6]
• Pathology
  • Hyperkeratosis, parakeratosis, acanthosis, and/or epithelial atrophy
  • Low-grade dysplasia is possible.
• Differential diagnosis: oral hairy leukoplakia in immunocompromised individuals
• Treatment
  • Smoking cessation
  • Cryotherapy, laser ablation
  • If lesions persist: surgical excision
• Follow-up: lifelong annual follow-up with biopsy of all recurrent or new leukoplakia ^[6][7]
• Complications: may develop into squamous cell carcinoma ^[8]

Although Bowen disease affects the skin and erythroplasia of Queyrat affects the mucous membrane, the precancerous lesions are histopathologically identical.

Bowen disease

• Definition: squamous cell carcinoma in situ (SCCIS) of the skin
• Etiology
  • Exposure to sun
  • Often associated with human papillomavirus (HPV) types 16 and 18
  • May be related to arsenic exposure
• Lesion
  • Commonly occurs on skin that is exposed to sun
  • Irregularly shaped and sharply defined borders
  • Erythematous and scaly
• Diagnostics: biopsy (confirmatory test)
• Treatment
  • Pharmacotherapy (e.g., 5-FU, imiquimod)
  • Photodynamic therapy
  • Surgical excision with a margin
• Prognosis
  • May progress to invasive cutaneous squamous cell carcinoma
  • Excellent prognosis if treated

Erythroplasia of Queyrat (Bowen disease of the glans penis)

• Definition: squamous cell carcinoma in situ (SCCIS) of the penile mucosa
• Etiology
  • Chronic irritation or infection
  • Lack of circumcision
  • HPV types 16 and 18
• Lesion
  • Most commonly preputium and glans penis affected
  • Single or multiple sharply demarcated, nonhealing lesions (e.g., plaques, red papules)
  • May ulcerate and bleed easily
• Treatment and prognosis: see Bowen disease