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Choroidal naevus

 

This is a benign ‘mole’ arising from melanocytes. It forms a grey, brown or yellow lump, either in the choroid, beneath the retina, or on the iris.

 

Choroidal naevus

Choroidal naevi are very common, being present in about one in ten individuals.

Choroidal naevi differ from malignant melanomas in that they usually:

  • have a thickness less than 2 mm;
  • do not cause symptoms;
  • do not leak significant amounts of fluid; and
  • do not have large amounts of ‘orange pigment’ on their surface.

 

Typical choroidal naevi are

  • flat
  • small
  • pigmented
  • featureless

 

typical_choroidal_naevus

Typical choroidal naevus

 

 Fig23-7

Typical choroidal naevus of the right eye, at the macula. The tumour is small, grey, flat and featureless.

 

Amelanotic choroidal naevus

Some choroidal naevi are amelanotic. These tend to be thin and not associated with retinal detachment.

 

amelanotic-choroidal-naevus

Amelanotic choroidal naevus

 

Atypical choroidal naevus

An atypical choroidal naevus can show any of the following features:

  • Dome shape
  • Drusen on surface
  • Overlying subretinal fluid
  • Depigmented 'halo'
  • Adjacent RPE disturbance forming a 'tail'
  • Overlying neovascular membrane

 

atypical_naevus

Atypical choroidal naevus with overlying drusen

 

choroidal-naevus-with-halo-and-tail

Atypical choroidal naevus with halo and tail