Ulcerated dermatofibroma or dermatofibrosarcoma protuberans?:: Differential diagnosis

Dermatofibroma (DF) is a common benign cutaneous tumor usually appearing as a slowly growing firm papule or nodule. Superficial erosion and ulcerations are infrequently seen and make an accurate clinical diagnosis difficult. Ulcerated DF (UDF) is a rare variant of DF reported recently. Histopathologically, destruction of the epidermis and the superficial dermis is expected. A 54-year-old woman presented with a painless nodule on the right ankle with 2 years of duration. Dermatologic examination revealed a moist and vegetative tumorous lesion, 4 cm in diameter, on her right lateral malleolus. Squamous cell carcinoma, pyogenic granuloma, malign eccrine poroma, Kaposi's sarcoma, dermatofibrosarcoma protuberans was suspected clinically. The lesion was surgically excised. The histopathologic diagnosis was UDF. We present this case because this uncommon variant of DF may cause diagnostic confusion.