Introduction:
The skin is the largest organ, and it acts as a barrier against thermal or physical agents. The three main layers of the skin include the epidermis (outer), dermis (middle), and hypodermis (inner). It constantly sheds the older cells and forms new cells. Any disturbance in the process of skin cell formation leads to abnormal and uncontrolled growth of skin cells, causing skin cancer. The abnormal skin cell growth remains benign (non-cancerous) or spreads to other areas (malignant).
The most common skin cancer are:
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Squamous cell carcinoma.
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Basal cell carcinoma.
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Melanoma.
What Is Bowen Disease?
JT Bowen was the first to report Bowen disease in 1912. The disease affects the epidermis of the skin. It is a rare, non-invasive, and pre-cancerous skin condition, also referred to as squamous cell carcinoma in situ. But there is less than a 10 % chance to turn into squamous cell carcinoma. Individuals above 60 years of age are more likely to develop such skin conditions.
What Causes Bowen Disease?
The causative agent of Bowen disease is not yet described. However, the following factors are found to increase the risk of it.
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Increased sun exposure.
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Older age.
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Drugs or treatment that suppresses the immune system.
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Human papillomavirus (HPV) type 16 is also linked with the development of Bowen disease.
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Long-term exposure to carcinogenic agents like arsenic.
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Radiation therapy.
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Chronic injury.
What Are the Clinical Manifestations?
The skin lesions develop more commonly on the sun-exposed areas of the skin, such as the lower legs, forehead, neck, and palms. It remains localized, but in rare cases (10 % to 20 %), it spreads to other skin areas.
The characteristic features are as follows:
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Reddish-brown scaly patches on the skin.
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It is slow-growing.
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Sometimes, it is itchy and bleeds.
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The lesion also becomes crusted and fissured.
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If infected, it oozes out.
How to Know About Cancerous Transformation?
As mentioned above, Bowen disease has less than a 10 % chance of developing into skin cancer. The risk of developing extragenital lesions is 3 % to 5 %, and the chance of genital lesions is 10 %. The signs that indicate malignant transformation are as follows:
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A fleshy bump (nodule) may develop on the skin patches.
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It is painful and bleeds easily.
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Ulcerated or hardened nodule.
How Is Bowen Disease Diagnosed?
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Skin Examination- The doctor thoroughly examines the skin lesion and looks for the presence of characteristic features of Bowen disease.
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Skin Biopsy - The skin lesion of Bowen disease is often confused with eczema or psoriasis. Thus, a skin biopsy provides a confirmatory diagnosis and differentiates it from other skin cancer. It involves the surgical removal of small tissue from the lesion to study under a microscope.
What Are the Related Disorders?
The skin disorders that resemble Bowen disease and need to be differentiated during diagnosis are listed down:
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Psoriasis - A chronic skin disorder that causes red, itchy, and scaly patches on the skin. The scalp, face, knees, elbows, and legs. Suppressed immune system and other triggering factors like infection, stress, injury, etc., initiate psoriasis. A biopsy is helpful in an appropriate diagnosis.
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Eczema - It is a skin inflammation causing dryness, itchiness, and rash. Children are commonly affected. Red patches and raised bumps on the skin are also observed. It is usually treated with topical and oral corticosteroids.
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Erythroplasia of Queyrat - It is Bowen disease occurring on the glans penis. The various clinical features include reddish plaques on the glans penis, which become ulcerated, crusted, and painful. The individual also suffers from bleeding and pain during urination.
How to Get Rid of Bowen Disease?
There are numerous treatment options available for Bowen disease. Factors like the age of the patient, size, and the number of lesions also determine the type of treatment and its outcome.
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Cryotherapy - The method involves freezing the skin lesion using liquid nitrogen. It is usually effective if the skin lesion is small and localized. Cryotherapy, also known as cryosurgery, is found to decrease recurrence. However, wound healing takes time, and various after-effects like pain and fluid-filled blisters may occur.
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Curettage and Electrocautery - Curettage is a procedure where the skin specialist scraps the skin lesion using a spoon-shaped instrument called a curette. Later the bleeding is controlled using heat generated by electricity, which is referred to as electrocautery. The healing occurs quickly and the pain and discomfort caused are less compared to cryotherapy.
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Chemotherapy - It necessitates the use of chemotherapeutic drugs to kill abnormal cells. Topical forms of Fluorouracil (5-FU) are more commonly indicated. The use of 5 % Fluorouracil twice daily for one to two weeks is found to clear away the skin lesions. The success rate increases if it is done in conjunction with immunotherapy, cryotherapy, or laser treatment. It is advised to protect the treated skin from sun exposure, as it causes inflammation.
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Immunotherapy - Certain drugs are used to aid the body’s immune system in fighting against cancer cells. Imiquimod, 5 % cream, is applied over the skin lesion. Initially, it may cause a burning sensation, and sometimes crusting and redness last two weeks post-treatment.
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Photodynamic Therapy (PDT) - The procedure uses a light source and light-sensitive drug to treat large affected areas of the skin. The skin specialist applies the light-sensitive cream to the lesion, and after 3 to 4 hours, the red, blue, or green light is passed over it for 10 to 15 minutes. Studies show that red light used in PDT is more effective than other lights.
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Laser Therapy - An intense beam of light destroys the abnormal cells. Carbon dioxide lasers are preferred in the treatment of lesions in fingers or genitals.
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Radiation Therapy - X-rays are utilized in treating abnormal cells. But, it is not preferred to treat lesions on lower legs, as it takes a longer time to heal.
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Surgical Treatment - Mohs micrographic surgery involves the removal of skin lesions layer by layer and is viewed under a microscope. The tissues are excised until it shows the absence of cancer cells. It's usually preferred for skin lesions around the anus and sometimes over the fingers and penis.
Conclusion:
Bowen disease is a slow-growing skin condition requiring periodic monitoring to check for malignant transformation. The dermatologist examines the skin lesion and decides the appropriate treatment based on the individual's age and the lesion's thickness and number. The prognosis is usually good after the treatment, but there are chances of recurrence. Therefore a follow-up is also essential for controlling its progression.
