The nevus spilus is a patch of melanization that is dotted by smaller macules of darker color. Nevus cells have been found on histopathologic examination. It is likely that the nevus spilus, in both its early and later stages, has been mistaken for the café au lait spot. The significance of the nevus spilus, its potentiality for malignant change, and some problems of melanotic macule nomenclature are presented.
Cohen HJ, Minkin W, Frank SB. Nevus Spilus. Arch Dermatol. 1970;102(4):433–437. doi:10.1001/archderm.1970.04000100081016