Please give me an example of the borders of a normal mole & that of cancerous one?

1 vs. 5 mm: When a benign nevus has fetures suggesting that transformation may eventually occur, a margin of 1-2 mm will suffice to guarantee complete removal. When there is a melanoma to be resected, depending on size, that is greater than 4mm thick and wide diameter, a margin of at least 5mm to 1 cm. may be necessary to guarantee complete removal of peripheral malignant cells to prevent local recur.