Answer to Dermacase continued from page 665
4. Bowen disease
Bowen disease (BD), also known as squamous cell carcinoma in situ, can occur at any age but is rare in people younger than 30 and more common in those older than 60 years.1 It has a predilection for sun-exposed areas of the body,2 as was the case with this patient, and it is 10 times more common in white people who live in sunny areas (142 per 100 000 people) than in those who live in more northern locations (14 per 100 000 people).3 The disease can be a result of sun exposure, arsenic exposure, ionizing radiation, immunosuppression, and some human papillomavirus infections.1,2
Bowen disease presents as a slow-growing, discrete, erythematous plaque with an overlying scale. If it is found in an intertriginous area it can be oozing, erythematous, scaling, or pigmented.1
Diagnosis
The differential diagnosis for BD is long. If erythematous, the disease can mimic superficial basal cell carcinoma, dermatitis, lichen planus, psoriasis, benign lichenoid keratosis, irritated seborrheic keratosis, actinic keratosis, squamous cell carcinoma, or amelanotic melanoma. If there is hyperkeratosis, physicians should consider verruca vulgaris, discoid lupus erythematosus, hypertrophic lichen planus, or squamous cell carcinoma. If pigmented, it could be melanoma or bowenoid papulosis. Intertriginous lesions resembling BD include inverse psoriasis, seborrheic dermatitis, candidal infections, Paget disease, or benign familial chronic pemphigus. Subungual and periungual disease appears similar to nail dystrophy, onychomycosis, squamous cell carcinoma, and amelanotic melanoma.1
Diagnosis is made by either punch or excision biopsy.2
Treatment
There are many treatment options for BD. Cryotherapy, curettage and cautery, excision, radiotherapy, 5-fluorouracil, lasers, photodynamic therapy, and imiquimod have all been used. No one treatment has been found to be superior for all cases. As such, each case must be considered on its own and the treatment options discussed with the patient.4 Two-year followup is recommended. The risk of progression to invasive carcinoma is estimated to be 3% to 5%.5
Avoiding excessive exposure to sunlight is the best preventive measure; many programs to that end are currently in place around the world.6,7
Footnotes
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Competing interests
None declared
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