Lentigines (Lentigo)

Definition/Appearance

  • A lentigo is a small, pigmented, flat/slightly raised spot with a clearly defined edge, surrounded by normal skin
  • They can appear slowly over years or more suddenly
  • They can appear anywhere on the body and can vary in colour from light/tan brown to black.
  • There are several types
    • Lentigo simplex (most common)
      • Usually appear at birth/early childhood; not associated with sun exposure (cf ephelides/true freckles); typically 5-15mm and dark
    • Solar lentigo (‘age-spots’ or ‘liver-spots)
      • Sun-induced lesion (appears on face, arms, hands); usually pale tan/pink  (can be darker) and <5mm although they may coalesce to form larger lesions; tends to appear in middle age (30-50) and most commonly seen in older individuals
    • Ink-spot lentigo
      • Resembles spot of ink (wiry/beaded irregular outline); occurs in sun-exposed areas, commonly surrounded by solar lentigines and most common in people of Celtic-origin.  Often hard to distinguish from melanoma
    • PUVA lentigo
      • Persistent, pale to dark brown macule appearing 6 months or more after the start of PUVA treatment.  Similar to solar lentigines but usually irregularly bordered.
    • Other types include radiation lentigo (associated with large radiation doses e.g. seen after chernobyl disaster); tanning bed lentigo (associated with tanning bed use); oral/labial (found on lips/mouth); genital lentigo; generalised lentigines (lentigines profusa- widespread multiple lesions of idiopathic origin); agminated lentiginosis (associated with other childhood diseases; distributed in a sharply demarcated region e.g. dermatomes)
  • May be associated with other systemic conditions e.g. LEOPARD; Peutz-Jeghers syndrome; Laugier-Hunziger syndrome; Myxoma syndromes e.g. LAMB; NAME and Carney’s syndrome

NB Lentigo maligna is a precancerous condition not discussed here

Investigations, Management

  • If concerned about diagnosis e.g. melanoma, skin biopsy is appropriate
  • If the patient is concerned about appearance, nitrogen therapy may lighten the lesion
  • Reassurance is mainstay- no treatment required

Histology

  • Increased proliferation of normal melanocytes, such that they replace the keratinocytes at the basal layer
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