Single lesions must first and foremost be suspected as being tumoral, benign, or malignant. An evolving lesion, which is heterogeneous, irregular, asymmetrical, or ­ulcerated, must be considered as malignant, particularly if it is pigmented. A dermal or deeper-seated nodule, ­especially when hard, must raise the possibility of a ­metastasis. Certain tumoral lesions have a characteristic clinical appearance (cylindroma, seborrheic keratosis, nodular basal cell carcinoma, etc.). Certain tumors are painful: eccrine spiradenoma, tricho- and angioleiomyoma, angiolipoma, neuroma, neurilemmoma (or schwannoma), glomus tumor, certain pilomatricomas, painful piezogenic papules, and painful nodule of the ear are the most typical. Numerous other palpable lesions can be ­painful (e.g., abscesses, erythema nodosum, granuloma annulare of the extremities). Biopsy provides the final ruling for any skin tumor which has not been clinically identified.