Intralesional (incision) biopsy for melanoma diagnosis: the rules and the exception.

Intralesional (incision) biopsy for melanoma diagnosis can be warranted for large lesions or for those lesions whose in-toto excision leads to cosmetic and/or functional impairment. However, this diagnostic approach carries a risk of underdiagnosis, if a clinicopathologic diagnostic approach is not implemented. As a rule, in large pigmented lesions from special body areas (scalp and acral skin), clinicodermoscopic differential diagnosis of melanoma includes non-melanocytic skin lesions, traumatic skin changes, and nevi. The unique indication to incision biopsy for the differential diagnosis between nevus and melanoma is a relatively small nodular proliferation developing within a medium-large congenital nevus.