Junction nevus is a well-known entity. As described by Lever1 and Allen,2 it is a relatively flat or slightly raised smooth pigmented mark that is usually devoid of hairs. The color is of various shades: light brown, brownish-black, and, rarely, slate blue or bluish-black. Eller3 states that it may be flint-colored or verrucous, exhibit abnormal hairy growth, and vary considerably in size; at times it is difficult to differentiate clinically from other types of nevi and neoplasms.
Junction nevus is a possible forerunner of nevo-carcinoma. As stated by Allen,2 about 12.5% of nevi in adults have a junctional component; only a small percentage of junction nevi change to malignant melanoma, but it is difficult to foretell which will become malignant. Most of them remain unchanged and inactive, may regress, or even may develop into some other forms, such as intradermal nevus, compound
BRAITMAN M. Junction Nevus with Spontaneous Clinical Disappearance. AMA Arch Derm. 1958;77(6):721. doi:10.1001/archderm.1958.01560060087017