Bowen’s Disease

Bowen’s disease is squamous cell carcinoma in situ of the skin. It is a very superficial form of skin cancer. This means that cancerous cells do not invade the skin below the epidermis (top level of the skin).

Risk factors:
Exposure to sunlight, especially when skin is fair, is a strong risk factor. Viral infection has been implicated, particularly human papillomavirus (usually HPV 16, but more rarely HPV 2). Other chemical carcinogens and trauma have been suggested, but often no specific risk factor is found. Exposure to arsenic is less important than it once was. Arsenic used to be found in Fowler’s solution used to treat psoriasis, Gay’s solution used to treat asthma, contaminated well water and some pesticides.

When associated with sunlight, the risk is much higher for whites. Some sources state that there is no difference in incidence between the sexes while others state that Bowen’s disease is 3 times more common in women than in men. It most commonly occurs in people between the ages of 60 and 70.

Examination:
Bowen’s disease presents as a slowly growing, red, flat or raised lesion. It is sharply demarcated and scaly with a pink or red surface. There may be a small erosion on the surface, or it may be crusted. The lesions vary in size from a few millimeters to a few centimeters. They are rarely pigmented. Lesions usually have no symptoms, but can bleed. They are often found on sites exposed to sun and are most common on the head and neck, followed by the limbs. Bowen’s disease may occur elsewhere, for example as a disorder of the vulva. When it arises on the glans penis, it is referred to as erythroplasia of Queyrat. Diagnosis is often delayed as Bowen’s disease does not bother patients and may appear similar to benign skin growths.

Management:
Biopsy is required for histological diagnosis.

Surgical excision
is usually suitable for small growths which are not on the face or digits. Although the lesion looks well circumscribed, it may extend beyond the apparent borders. Therefore, at least 5mm of clear skin needs to be excised around the visible growth.

Mohs micrographic surgery is excellent for larger lesion and those on the face or digits, where it is important to be as sparing as possible with the extent of excision.

Cautery, curettage and cryotherapy may be satisfactory, but they give no histopathological diagnosis and may fail to reach all the affected tissue.

Superficial x-ray treatment may be best for those inappropriate for surgery, especially with multiple lesions. Topical 5% fluouracil cream and imiquimod cream may be used.

Photodynamic therapy (PDT)
may be valuable.
Prognosis is excellent, especially with treatment. Untreated, 3 to 5% progress to invasive squamous cell carcinoma, and metastases are rare.

Valerie Nozad, D.O.
Department of Dermatology
Philadelphia College of Osteopathic Medicine/Frankford Hospital
Philadelphia, Pennsylvannia.