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Eye cancer

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Precancerous conditions of the eye

Precancerous conditions have the potential to develop into cancer. Atypical moles have the potential to develop into intraocular melanoma.

Atypical moles

An atypical mole on the skin, also known as a dysplastic nevus, has some of the same characteristics as a melanoma of the skin, but it is not cancerous. Moles occur when the pigment-producing cells called melanocytes grow together in a group. People can have abnormal brown spots like an atypical mole on or in the eye.

Risk factors

Atypical moles may occur without a known cause (occur sporadically). However, some conditions can increase the risk of developing eye or skin moles and are associated with an increased risk of melanoma of the eye:

  • ocular melanocytosis (also called oculodermal melanocytosis or nevus of Ota) – areas of increased pigmentation of the eye
  • familial atypical multiple mole melanoma (FAMMM) syndrome (sometimes called dysplastic nevus syndrome) – an inherited condition in which people have a large number of moles on their body
  • primary acquired melanosis (PAM) – increased pigmentation of the conjunctiva of the eye

Signs and symptoms

Atypical moles look different from normal moles. They tend to be unusual (atypical) in size and shape. Atypical moles are larger (at least 5 mm) than other moles and have an irregular shape with undefined borders.


If the signs and symptoms of atypical moles are present, or if the doctor suspects an atypical mole syndrome, tests will be done to make a diagnosis. Tests may include:

medical history and physical examination

eye examination


Regular observation of atypical moles or other atypical pigmentation of the eye is usually done.


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