Traumatic keratoacanthoma arising in a 15-year-old boy following a motor vehicle accident.

Keratoacanthomas appear most commonly in sun-damaged skin in middle-aged and elderly people. We present a 15-year-old boy who developed a rapidly growing nodule within a hypertrophic scar that was the result of trauma suffered in a roll-over motor vehicle accident 8 months prior to presentation. Histologic analysis of a biopsy specimen of the nodule confirmed the presence of squamous cell carcinoma, keratoacanthoma type. The development of keratoacanthoma has been associated with sun exposure, chemical carcinogens, radiation therapy, genetic factors, and various forms of antecedent trauma, including surgery or grafting, thermal burns, laser resurfacing, and vaccination. This report describes the youngest patient with traumatically-induced keratoacanthoma, and is the first instance of this entity arising in a friction burn.