Mole Recurrent Previously Excised Nevi
Weeks to months after incomplete removal of a nevus, brown macular pigmentation may appear in the scar. Some nevus cells remain with shave excision and partial repigmentation is possible. Randomly distributed pigmentation along with scar can be quite suspicious for melanoma. Residual pigmentation may be removed with electrocautery or cryosurgery. An unusual histologic picture resembling melanoma (pseudomelanoma) may follow partial removal of a nevus. If the repigmented area is excised, the pathologist should always be notified that the submitted tissue was acquired from a previously treated area. Histologically, the melanocytes appear atypical but are confined to the epidermis, and there is no lateral spread of individual melanocytes. The history of previous biopsy and a review of the original specimen are critical to the correct diagnosis.