Lentigo means freckle. A malignant lentigo means a malignant freckle, which occurs on the faces of the very elderly. A lentigo, without the word malignant attached to it, is just a freckle. I think the dermatologist was happy it's off, because he thought you'd stop worrying about it; unfortunately, he seems to have achieved the opposite. Please call him to clarify so you won't worry any more.