What is Bowen's disease?

What is Bowen's Disease?

Bowen's disease is an intraepidermal (in situ) squamous cell carcinoma, meaning it is a form of skin cancer confined to the epidermis that has not yet invaded deeper tissues. 1

Definition and Terminology

• Bowen's disease is synonymous with squamous cell carcinoma in situ (SCC in situ) for non-genital skin lesions, originally described in 1912. 1
• Current practice favors the term "squamous cell carcinoma in situ" over the eponym "Bowen's disease" in line with reduced use of eponyms. 1
• The disease is characterized by full-thickness epidermal dysplasia on histological examination. 1

Clinical Presentation

Bowen's disease typically presents as a well-demarcated, erythematous hyperkeratotic plaque with an irregular border and surface crusting or scaling. 1

Key Clinical Features:

• Gradually enlarging red plaque that may be mistaken for eczema or psoriasis 1
• Well-defined borders with irregular edges 1
• Surface may show scaling, crusting, or hyperkeratosis 1
• Usually solitary, but 10-20% of patients have multiple lesions 1

Demographics and Epidemiology

• Peak incidence occurs in the seventh decade of life 1
• Predominantly affects women (70-85% of cases) in U.K. populations 1
• Annual incidence estimated at 15 per 100,000 in the U.K., though this may vary based on sun exposure patterns 1
• Most common sites are sun-exposed areas, particularly head and neck (29-54%), though lower limbs are more commonly affected in women 1
• In U.K. populations specifically, 60-85% of lesions occur on the lower legs 1

Etiological Factors

Primary Risk Factors:

• Ultraviolet radiation exposure (solar, iatrogenic phototherapy, sunbeds) is the most common cause 1
• Arsenic exposure (lesions may arise in sun-protected areas) 1
• Ionizing radiation including previous radiotherapy 1
• Immunosuppression, particularly therapeutic immunosuppression (23% of skin cancers in renal transplant recipients are Bowen's disease) 1
• Human papillomavirus (HPV), especially HPV 16, is strongly associated with genital and perianal lesions, and detected in 29-58% of extragenital lesions 1

Clinical Variants

Less common presentations include:

• Pigmented Bowen's disease 1
• Subungual/periungual lesions 1
• Palmar lesions 1
• Genital lesions (erythroplasia of Queyrat in males, vulval intraepithelial neoplasia) 1
• Perianal lesions 1
• Verrucous Bowen's disease 1

Diagnosis

• Clinical diagnosis can be made based on appearance, potentially aided by dermoscopy showing glomerular vessels and scaling 1, 2
• Punch biopsy is required for confirmation when there is diagnostic doubt or before certain treatments 1
• Punch biopsy is preferable to curette biopsy as it allows visualization of full-thickness epidermis and dermis to exclude invasive disease 1
• Histopathology remains the gold standard for definitive diagnosis 3

Risk of Progression

• The risk of progression to invasive squamous cell carcinoma is 3-5% for extragenital lesions 4, 5
• Approximately 10% of genital lesions progress to invasive disease 4
• One-third of invasive tumors that develop may metastasize 5
• Erythroplasia of Queyrat (penile Bowen's disease) carries the highest risk, with approximately 60% of penile SCCs occurring on a background of this precursor lesion 6

Important Clinical Distinctions

Bowen's disease specifically refers to non-genital cutaneous lesions, while genital variants have distinct terminology and management:

• Erythroplasia of Queyrat (penile lesions) 1, 6
• Vulval intraepithelial neoplasia (VIN) 1
• Bowenoid papulosis (either sex) 1

These genital variants have strong HPV associations and often require different therapeutic approaches than extragenital Bowen's disease. 1