Can you identify this painful papule?

Dermclinic
A Photo Quiz to Hone Dermatologic Skills

Case 3:
A 53-year-old man reports that the painful growth on his upper chest wall had been rubbed by a seat belt 1 week earlier. The lesion had been asymptomatic for months before becoming irritated.

Which of the conditions in the differential is the likely diagnosis?

A. An irritated seborrheic keratosis.
B. An inflamed actinic keratosis.
C. A lichenoid keratosis.
D. A squamous cell carcinoma.
E. A keratoacanthoma.

(Answer on next page.)

Dermclinic—Answer

Case 3: Irritated seborrheic keratosis

A shave biopsy confirmed the clinical impression of an irritated seborrheic keratosis, A. The lesion’s dome shape likely excluded actinic keratosis, but squamous cell carcinoma and keratoacanthoma remained in the differential. Lichenoid keratoses are usually flatter and less inflamed.

A punch biopsy is also appropriate; excisional biopsy is a more extensive procedure than is needed for diagnosis. Cryosurgery may be done for a seborrheic keratosis, but squamous cell carcinomas and keratoacanthomas do not resolve with this therapy and a biopsy is needed at follow-up. If an antibiotic is prescribed, schedule a 1- to 2-week follow-up for biopsy or cryosurgery if needed. The shave biopsy was curative in this patient.   ■