Likelihood of finding melanoma when removing a melanocytic lesion with peripheral clods.

Naevi typically involute after the fourth decade of life and are rare in the elderly. However, the rate at which naevi disappear with age varies greatly with some individuals still having large numbers of naevi in late middle age. A small subset of compound naevi in adolescence exhibits a peripheral rim of small brown clods. These naevi enlarge symmetrically with time, accompanied by a progressive development of reticular pattern until the disappearance of the peripheral clods that indicates their growth stabilization. On the other hand, a melanocytic lesion that shows a growth after the age of 30 should raise the doubt of being a melanoma and should thereafter be considered as candidate for excision. In a clinical setting, common behaviour is to excise a melanocytic lesion that shows growing parameters (like a peripheral rim of clods) after 35 years old.