Which of the following images requires a biopsy?

Dermatofibrosarcoma protuberans (DFSP), dermatofibromas, keloids and hypertrophic scars are four separate conditions requiring assessment, but only one requires a biopsy.

Clinically, DFSP lesions may be mistaken for keloids (photo 2), however keloids are benign growths with no metastatic potential and are the consequence to aberrant scar formation. Keloids extend beyond the site of injury, unlike hypertrophic scars (photo 3), which are confined to the site of injury. Dermatofibromas (photo 4) are benign dermal proliferation of fibroblasts.