Illustration showing the tentacle-like projections of many malignant skin tumors and how surgical margins are assessed. Dirty margins indicate the tumor is incompletely removed. Narrow, complete margins may give a false sense of security. Wide, complete margins indicate adequate surgical excision and represent the gold standard. Confusion may arise when reports say margins are complete, but they may not be adequate (ie, wide enough to prevent recurrence due to residual cancer cells left in the tumor bed).