When an atypical mole has been identified, a skin biopsy takes place in order to best diagnose it. Local anesthetic is used to numb the area, then the mole is biopsied. The biopsy material is then sent to a laboratory to be evaluated by a pathologist. A skin biopsy can be a punch, shave, or complete excision. The complete excision is the preferred method, but a punch biopsy can suffice if the patient has cosmetic concerns (i.e. the patient does not want a scar) and the lesion is small. A scoop or deep shave biopsy is often advocated, but should be avoided due to risk of a recurrent nevus, which can complicate future diagnosis of a melanoma, and the possibility that resulting scar tissue can obscure tumor depth if a melanoma is found to be present and re-excised.