Can you identify this erythematous lesion?

This solitary, nonresolving erythematous lesion has been present on the mid thigh of a 73-year-old woman for several months. She reports that the lesion is asymptomatic, has not changed in size, and has never bled.

What do you suspect?

A. Irritated seborrheic keratosis.
B. Basal cell carcinoma.
C. Squamous cell carcinoma.
D. Bowen’s disease, or squamous cell carcinoma in situ.
E. Amelanotic melanoma.

(Answer on next page.)

Answer: Bowen’s disease, or squamous cell carcinoma in situ

All of the diagnoses in the differential are reasonable based on the history and appearance of the lesion. A biopsy of the site revealed Bowen’s disease, or squamous cell carcinoma in situ, D.

Often arising on sun-exposed areas or in persons who have been exposed to arsenic, Bowen’s plaques can be removed by simple curettage and electrodesiccation. In this case, such treatment was curative. Follow-up is important because recurrences are fairly common. Failure to remove the lesion may result in invasive carcinoma.