Condition	Distinguishing characteristics
Seborrheic keratosis	“Stuck-on” appearance, symmetric, often multiple
Traumatized or irritated nevus	Returns to normal appearance within 7 to 14 days
Pigmented basal cell carcinoma	Waxy appearance, telangiectasias
Lentigo	Prevalent in sun-exposed skin, evenly pigmented, symmetric
Blue nevus	Darkly pigmented from dermal melanocytes, no history of change
Angiokeratoma	Vascular tumors, difficult to distinguish from melanoma
Traumatic hematoma	May mimic melanoma but resolves in 7 to 14 days
Venous lake	Blue, compressible, found on ears and lips
Hemangioma	Compressible, stable
Dermatofibroma	Firm growths of fibrous histiocytes, “button-hole” when pinched
Pigmented actinic keratosis	Sandpapery feel; sun-exposed areas