What is a lentigo (pigment spot)?
A lentigo (plural: lentigines) is a very common, benign pigmented skin lesion that occurs in people of middle to older age. People with a fair skin type and a lot of past sun exposure in particular are at increased risk. A large proportion of people aged 65 and over have one or more lentigines. The spots are seen mainly on the face and the backs of the hands. Other names for a lentigo are pigment spot, sun spot, solar lentigo or liver spot.
How does a pigment spot develop?
There is a clear link between the development of pigment spots and the amount of sunlight the skin has been exposed to over life. The pigment-producing cells, the melanocytes, produce too much pigment.
What does it look like?
Lentigo. A lentigo is typically an evenly brown-pigmented, sharply bordered oval or irregularly bordered flat pigment spot, from a few millimetres to a few centimetres across.
Lentigo maligna. By far the most lentigines are completely benign. In some, however, malignant pigment cells can develop; such a lentigo is then called a lentigo maligna. In fact lentigo maligna is the last stage before melanoma, the most malignant form of skin cancer. A lentigo maligna is distinguished from an ordinary lentigo by variable and irregular pigmentation. For lentigines that change or cause complaints, a doctor should be consulted.
How is the diagnosis made?
Usually the diagnosis can be made with the naked eye. In case of doubt, it is examined with a dermatoscope (a hand-held skin microscope), or a biopsy is even taken so the tissue can be examined further by the pathologist.
How is a pigment spot treated?
Because a lentigo is benign, it does not need to be treated. When removal is desired for cosmetic reasons, there are two options: freezing with liquid nitrogen, or laser therapy. With freezing, the superficial pigment-containing skin cells are frozen and replaced by new cells without excess pigment; a relative drawback is that freezing slightly too long can cause a scar. Removal with the ruby laser is regarded by many as the treatment of choice, with a very small chance of scarring; a drawback is the relatively high cost. With both treatments the lentigo regularly returns over time.
When to see a doctor
See a doctor if a pigment spot becomes unevenly or irregularly coloured, changes, or causes complaints, so a lentigo maligna can be ruled out.