What is a lentigo?
A lentigo (plural lentigines) is a small, pigmented flat or slightly raised spot with a clearly defined edge that is surrounded by normal-appearing skin. Lentigo or lentigines may evolve slowly over years, or they may appear suddenly. They may occur anywhere on the body and vary in colour from tan-brown to black. Viewed under the microscope a lentigo shows an increased number of normal melanocytes (skin cells that produce the pigment melanin that produces skin colour). Melanocytes appear to replace keratinocytes in the basal layer of the epidermis.
Although lentigines are benign (non-cancerous) by nature they must be carefully examined to differentiate them from early pigmented skin cancers such as melanoma.
What are the clinical features of lentigines?
Lentigines have been classified into many different types depending on what they look like, where they appear on the body, causative factors, and whether they are associated to other diseases or conditions.
|Lentigo simplex||Most common form of lentigo that appears at birth or in early childhood. Not necessarily associated to sun exposure or any medical conditions. Small dark papule, sometimes with dry surface.|
|Solar lentigo (see Brown spots and freckles)||Commonly known as age spots or liver spots. Benign sun-induced lesion that occurs in sun-exposed areas, e.g. face, arms, hands. Not associated with any medical conditions.|
|Ink-spot lentigo||Usually a single black spot among a number of solar lentigines. Occur most commonly in patients of Celtic ancestry.|
|PUVA lentigo||Persistent, pale to dark brown flat spot appearing 6 months or longer after the start of PUVA therapy. Similar in appearance to solar lentigines but lesions often have more irregular borders.|
|Radiation lentigo||Similar to sun-induced lesions but often associated with signs of other long-term skin radiation damage such as epidermal atrophy, SC fibrosis, keratosis and telangiectasias. Does not appear to occur after local radiation therapy but from exposure to a large single dose of ionising radiation (e.g. exposure from the Chernobyl nuclear accident)|
|Tanning-bed lentigo||Usually occurring in women with a history of tanning-bed use. Lesions may appear soon after exposure or they may appear after prolonged regular use of tanning beds.|
|Oral and labial melanotic macules||Appear as a single, small (<4mm) lesion on the red part of the lower lip (labial) and inside the mouth on the gums, inside of the cheeks, roof of the mouth and tongue. Sometimes seen in syndrome-associated lentigines. Also called labial melanosis.|
|Vulvar and penile lentigo||Similar to labial melanotic macules. Occur on the penis and female genitalia. Lesions have irregular borders and vary in colour from tan to dark brown. Lesions may also occur in episiotomy scars after childbirth.|
|Lentigines profusa||Also known as generalised lentigines and is characterised by numerous lentigines without signs of associated conditions or triggering factors. The many small lesions may join together to form coloured patches. Often involves the extremities, trunk, palms and genitalia.|
|Agminated lentiginosis||Numerous lentigines confined to a body segment, with a sharp demarcation at the midline. Usually appears in early childhood and is associated with many other diseases.|
|Inherited patterned lentiginosis||Occurring in black coloured people, this is characterised by hyperpigmented spots mainly on the face and lips. Inheritance pattern appears to be autosomal dominant.|
|Syndrome-associated lentigines||Xeroderma pigmentosum, LEOPARD, Peutz-Jeghers, Laugier-Hunziker, myxoma syndromes (LAMB, NAME, Carney). Click on individual disease syndrome for further information.|
How is the diagnosis made?
Lentigines are usually diagnosed clinically by their typical appearance.
If there is any doubt about the diagnosis, they may be excised for histopathology (biopsy). Increased pigmentation is found at the base of the epidermis with varying patterns according to the type of lentigo.
What treatments are available for lentigines?
Lentigines require no specific treatment. A broad-spectrum sunscreen may help to prevent further appearance and darkening of solar lentigines. Several creams may lighten lentigines if applied for a number of months. These include hydroquinone or antioxidants such as:
- Book: Textbook of Dermatology. Ed Rook A, Wilkinson DS, Ebling FJB, Champion RH, Burton JL. Fourth edition. Blackwell Scientific Publications.
On DermNet NZ:
- Lentigo – Medscape Reference
Books about skin diseases:
See the DermNet NZ bookstore