A lentigo is a small pigmented spot on the skin with a clearly-defined edge, surrounded by normal-appearing skin. It is a harmless (benign) hyperplasia of melanocytes which is linear in its spread. This means the hyperplasia
Hyperplasia means increase in number of cells/proliferation of cells. It may result in the gross enlargement of an organ and the term is sometimes mixed with benign neoplasia/ benign tumor....

 of melanocytes is restricted to the cell layer directly above the basement membrane
Basement membrane
The basement membrane is a thin sheet of fibers that underlies the epithelium, which lines the cavities and surfaces of organs including skin, or the endothelium, which lines the interior surface of blood vessels.- Composition :...

 of the epidermis where melanocytes normally reside. This is in contrast to the "nests" of multi-layer melanocytes found in moles
Melanocytic nevus
A melanocytic nevus is a type of lesion that contains nevus cells .Some sources equate the term mole with "melanocytic nevus". Other sources reserve the term "mole" for other purposes....

 (melanocytic nevi). Because of this characteristic feature, the adjective "lentiginous" is used to describe other skin lesions that similarly proliferate linearly within the basal cell layer.

Lentigines are distinguished from freckles (ephelis) based on the proliferation of melanocytes. Freckles have a relatively normal number of melanocytes but an increased amount of melanin
Melanin is a pigment that is ubiquitous in nature, being found in most organisms . In animals melanin pigments are derivatives of the amino acid tyrosine. The most common form of biological melanin is eumelanin, a brown-black polymer of dihydroxyindole carboxylic acids, and their reduced forms...

. A lentigo has an increased number of melanocytes. Freckles will intensify and fade with sunlight exposure, whereas lentigines will stay stable in their color regardless of sunlight exposure.

Conditions characterized by lentigines include:
  • Lentigo simplex
    Lentigo simplex
    Lentigo simplex is the most common form of lentigo. A single lesion or multiple lesions may be present at birth or more commonly first develop in early childhood. Lentigo simplex is not induced by sun exposure, and it is not associated with any medical diseases or conditions...

  • Solar lentigo (Liver spots)
  • PUVA lentigines
  • Ink spot lentigo
    Ink spot lentigo
    Ink spot lentigo is a cutaneous condition characterized by skin lesions commonly occurring on the shoulders....

  • LEOPARD syndrome
    Leopard syndrome
    LEOPARD syndrome - is part of a group called Ras/MAPK pathway syndromes - is a rare autosomal dominant, multisystem disease caused by a...

  • Mucosal lentigines
    Mucosal lentigines
    Mucosal lentigines is a cutaneous condition characterized by light brown macules on mucosal surfaces....

  • Multiple lentigines syndrome
  • Moynahan syndrome
    Moynahan syndrome
    Moynahan syndrome is a cutaneous condition characterized by multiple lentigines, congenital mitral stenosis, dwarfism, genital hypoplasia, and mental deficiency.It was characterized in 1962.It is one of three conditions named for Edmund John Moynahan....

  • Generalized lentiginosis
    Generalized lentiginosis
    Generalized lentiginosis is a cutaneous condition that will occasionally present without other associated abnormalities. It may be caused by carney complex, LEOPARD syndrome or Peutz–Jeghers syndrome....

  • Centrofacial lentiginosis
    Centrofacial lentiginosis
    Centrofacial lentiginosis is a cutaneous condition characterized by lentigines on the nose and adjacent cheeks....

  • Carney complex
    Carney complex
    Carney complex, also known as LAMB syndrome and NAME syndrome is an autosomal dominant condition comprising myxomas of the heart and skin, hyperpigmentation of the skin , and endocrine overactivity It is distinct from Carney's triad...

  • Inherited patterned lentiginosis in black persons
    Inherited patterned lentiginosis in black persons
    Inherited patterned lentiginosis in black persons is a cutaneous condition inherited in an autosomal dominant fashion, presenting in infancy or early childhood....

  • Partial unilateral lentiginosis
    Partial unilateral lentiginosis
    Partial unilateral lentiginosis is a cutaneous condition characterized by lentigines located on only one half of the body....

  • Peutz-Jeghers syndrome
    Peutz-Jeghers syndrome
    Peutz–Jeghers syndrome, also known as hereditary intestinal polyposis syndrome, is an autosomal dominant genetic disease characterized by the development of benign hamartomatous polyps in the gastrointestinal tract and hyperpigmented macules on the lips and oral mucosa...

  • Acral lentiginous melanoma
    Acral lentiginous melanoma
    Acral lentiginous melanoma is a kind of lentiginous skin cancer skin melanoma.Acral lentiginous melanoma is observed on the palms, soles, under the nails and in the oral mucosa. It occurs on non hair-bearing surfaces of the body which may or may not be exposed to sunlight. It is also found on...

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