Dermatofibromas are common among adults, more so in women. Their cause is probably genetic. Lesions are usually 0.5 to 1 cm in diameter, firm, and may dimple inward with gentle pinching. Most lesions are asymptomatic, but some itch or ulcerate after minor trauma.
Diagnosis of dermatofibromas can often be made clinically. Lesions are sometimes biopsied to exclude melanocytic proliferation (eg, nevus, solar lentigo, melanoma) or other tumors.