DermaDiagnosis
There’s More Where That Came From
The single scaly lesion on this 21-year-old man's chest has now multiplied by 20. What is the explanation for this spreading rash?
ANSWER
The correct answer is perform a shave biopsy (choice “c”). It is a bedrock principle in dermatology that there is no substitute for a correct diagnosis, because correct diagnosis dictates proper treatment. When practical, biopsy is an excellent way to establish the true nature of a lesion and rule out other possibilities; it cuts through all conjecture.
DISCUSSION
The report showed intraepidermal squamous cell carcinoma, also known as Bowen disease. In this case, overexposure to the sun was the probable cause; however, Bowen disease can also develop from non–UV-related triggers, including human papillomavirus, arsenic (usually in contaminated ground water), and radiation treatment.
The differential includes psoriasis (which waxes and wanes), fungal infection (unlikely to last 10 years with so little growth), and superficial basal cell carcinoma.
Treatment success can be achieved by electrodessication and curettage or by the application of 5-fluorouracil or imiquimod cream for a month or two. Rarely, Bowen lesions can become invasive and metastasize if left untreated.
This patient’s prognosis, however, is excellent—at least, as far as this lesion is concerned. His history of sun exposure and numerous skin cancers means he still needs regular visits to dermatology.
