Optometry case study: Naevus or melanoma?

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by Shivan Sivakumaran, Specsavers Hornby, NZ

History

Px: 54-year-old male
Reason for visit: Presented reporting worsening near vision, with no other reported issues
Meds: Gout and depression medication
POH: Last eye test was 3 years ago (Figure 1). Had an episode(s) of epicleritis that was treated by a specialist
FOH: No relevant family ocular history known

Figure 1. Retinal photo of RE in 2013 (last examination)

Clinical assessment
Refraction: Small hyperopic, astigmatic refraction and presbyopia
Best corrected acuities: R: 6/5  L: 6/5
IOPs: Normal

Ocular health assessment
Largely normal apart from a pigmented choroidal lesion seen in the posterior pole (Figure 2). Suspicious disc appearance, infero-temporal thinning, possible superior nasal shelving.

Figure 2. Retinal photo of RE from most recent examination (2016)
Figure 3. Animation showing the change in the lesion’s appearance between 2013 and 2016

Diagnosis

Differential diagnosis

  • RE choroidal naevus
  • RE choroidal melanoma
  • RE choroidal metastasis (i.e. malignancies where the primary tumour is elsewhere)
  • RE CHRPE (congenital hypertrophy of the RPE)
  • RE choroidal hemangioma
  • RE choroidal osteoma

Management

  • First time multifocal recommended and VF 24-2 test performed for suspicious optic nerves
  • Referred to hospital to enquire about suspicious naevus change
  • Explained to patient that they had an “eye freckle” that had changed in appearance
  • In terms of record keeping, both written and retinal photographs were documented
  • Hospital diagnosed lesion as non-suspicious (i.e. choroidal naevus)
  • However, due to altered appearance, the hospital will review in 6 months’ time

Discussion

Extra testing to assist with differentiating features of pigmented lesions include:

  • A dilated fundus examination to better examine the lesion
  • Close observation over a time period
  • OCT to determine if lesion is raised or any other suspicious findings
  • Visual field testing and Amsler grid testing.

Further ophthalmological tests could include:

  • Biopsy (spindle vs epithelioid)
  • Ultrasound B-scan.

A useful pneumonic for differentiating / assessing risk of naevus vs melanoma is described below:

  • To – Thickness
  • Find – Fluid

a

  • Small – Symptoms
  • Ocular – Orange pigment
  • Melanoma – Margin touching disc

Editor’s note: Differentiating between benign and malignant pigmented lesions can be quite difficult. In this case, with regards to the pigmented lesion, where there was a change in appearance over time in an adult, it is regarded as suspicious. Appropriate investigations should be completed to rule out malignancy. The rate of a choroidal naevus changing to a malignant melanoma has been estimated at 1 in 8,8451. Although this is a relatively small risk, the potential for sight- and life-threatening effects mean regular monitoring of naevi is essential.

References
1. Singh AD et al. Ophthalmology. 2005;112(10):1784-1789

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