This is particularly true with such lesions as cavernous hemangioma, lymphangioma, and juvenile xanthogranuloma. The frequency of pigmented lesions of the eyelid varies according to the lesion type and patient characteristics. Environmental characteristics play a role, with the frequency of benign and malignant eyelid lesions increasing in areas closer to the equator. Pigment-producing cells derive embryologically from the neural crest. These cells are destined to reside in the basal cell layer of the epidermis.
Melanocytes are melanin-producing cells found in the basal cell layer of the epidermis.
Nevus cells are incompletely differentiated melanocytes that are found in clumps in the epidermis or the dermis. Nevus cells may or may not produce pigment and, therefore, can be classified as melanotic or amelanotic. Congenital nevi acquire pigmentation at puberty, at which time they slowly migrate from the epidermis to the dermis. Coincident with this decent, nevi become less active and, therefore, less capable of converting into a malignant lesion. The most active nevus is the junctional nevus.