CLINICAL APPLICATION QUESTIONS
A 44-year-old man requests evaluation of an irritated brown lesion on his left shoul- der. Evaluation reveals a typical 5-mm “stuck on” seborrheic keratosis. He also has mul- tiple lentigines of various sizes in a solar distribution over his upper back, shoulders, and upper chest. An asymmetric multicolored 4 × 8 mm lesion is present on his left anterior shoulder. It has a notched margin and stands out from the other lesions.
1. Should the multicolored lesion be biopsied?
2. What are the primary lesions that you would expect to find in solar lentigines?
3. What are the secondary lesions that you would expect to find in solar lentigines?
4. What should you tell the patient about the solar lentigines?
5. Is there any relationship between lentigines and melanoma?
6. How are solar lentigines treated?
APPLICATION GUIDELINES Specific History
A lentigo is a focal area of numerically increased, but benign, nonproliferating melanocytes at the dermoepidermal junction. There are two common types: small nonso- lar lentigines and larger sun-induced lentigines. Most nonsolar lentigines arise during the first decade, but they may increase in number into adulthood or occasionally arise later in life. Solar lentigines begin in the second decade of life, except with intense solar exposure, when they may appear even earlier.
Evolution of Disease Process and Skin Lesions
Once present, nonsolar lentigines are quite stable. They do not change in color or number with solar exposure. Spontaneous disappearance has been recorded. This type of lentigo is usually dark brown and tends to be more discrete, symmetrical, and less densely grouped than ephelides. They show fewer tendencies toward confluence. Even confluent lentigines rarely exceed 0.5 cm in size.
A solar lentigo is microscopically identical to its nonsolar counterpart. This type is usually 0.5 to 1 cm or more in size and appears after acute or chronic sun exposure. The margins are irregular, but like nonsolar lentigines, the normal skin lines can be readily fol- lowed across the lesion’s surface. Both are absolutely macular.
From: Current Clinical Practice: Dermatology Skills for Primary Care: An Illustrated Guide D.J. Trozak, D.J. Tennenhouse, and J.J. Russell © Humana Press, Totowa, NJ