How do liver spots, solar lentigo, and lentigo senilis differ?

Liver spots, age spots, and the more proper dermatologic terms solar lentigo and lentigo senilis all refer to the same entity. More than one half of all patients over age 64 will have at least one solar lentigo, and most patients have more than one. Clinically, they are flat to slightly raised, tan to brown lesions on sun-exposed skin, most commonly on the dorsum of the hands, forearms, and face, where they are the result of excessive cumulative UV light exposure. Microscopically, solar lentigos demonstrate elongation of the rete ridges (lentiginous hyperplasia) and increased numbers of melanocytes that produce more than the normal amount of melanin. They may be removed with a light freeze of liquid nitrogen, various types of chemical peels, 2% mequinol/0.01% tretinoin, or special lasers. They may also be temporarily bleached with over-the-counter (1% to 2% concentration) or prescription (3% to 4% concentration) hydroquinone creams.

Farris PK: Combination therapy for solar lentigines, J Drugs Dermatol 3:S23–S26, 2004.