Optometry case study: Peripheral retinal pigmentation

1374

by An Tran, Specsavers Mill Park, VIC

History

Px: 20-year-old male of African descent. First eye test
Reason for visit: Noticed a dull pain in the RE after computer usage. Felt unaided vision for both distance and near were clear
GH: No issues disclosed upon presentation, however, after further questioning post-examination, reported that he experienced frequent bowel issues
POH: None. No spectacles in the past
FOH: Nil glaucoma / AMD. One maternal aunt had retinitis pigmentosa

Examination

Pupils: PERRLA
Ocular motility: Full and smooth
Unaided VA:
RE: 6/6-2
LE: 6/120
Refraction:
RE: +0.25/-0.75×175 6/6
LE: -2.75DS correcting VA to 6/7.5
Anterior segment: Unremarkable, no abnormalities R & L
Posterior segment: Healthy macula and optic nerves R & L. Both eyes had extensive mid-peripheral to far peripheral pigmentary changes. Multiple 20+ flat, roundish, well-defined pigmented lesions located in all quadrants. Size of largest pigmented lesions ~1/4DD
Visual field on Humphrey Matrix 24-2: No significant or specific defects in R&L. Reliable indices

Diagnosis

Refractive diagnosis:

  • Refractive: RE – hyperopic astigmatism. LE – refractive amblyopia

Ocular health differential diagnosis:

  • Multiple congenital hypertrophy of the retinal pigment epithelium (CHRPE), associated with familial adenomatous polypopsis (FAP)
  • Retinitis pigmentosa
  • Ocular melanosis

Management

Referred patient to a retinal specialist for further testing. Encouraged patient to advise family members to have an eye examination. Also advised patient that due to the extent of the lesions, and depending on ophthalmologic findings, he may require a colonoscopy or genetic testing in the future.

Ophthalmologist report: Several retinal specialists were consulted and the patient was considered to have an unusual and more extensive presentation of regular CHRPE.

Due to the extent of the lesions, he was advised to attend the Royal Melbourne Hospital’s Colorectal Genetics Department to undergo genetic testing for the APC (adenomatous polyposis coli) gene and a colonoscopy. His family members were also encouraged to have eye tests and a comprehensive check of their retina.

Discussion

CHRPE is a common presentation seen in optometry primary care clinics. This case highlights the need to differentiate between different CHPRE presentations – particularly those with wider systemic health implications.

CHRPE is typically benign, appearing as a flat, well-defined and pigmented lesion on the retina. There are three subtypes:

  • Solitary CHRPE
  • Grouped CHRPE, termed ‘bear-track CHRPE’
  • Multiple CHRPE, pathognomonic for FAP.

Solitary CHRPE is clinically insignificant, with no accompanying ocular symptoms or associated systemic health issues. Malignant transformations of CHRPE into adenocarcinoma are extremely rare1. However, patients with CHRPE should be regularly monitored for changes, preferably with photographic documentation. Solitary CHRPE is not associated with increased incidence of FAP or gastrointestinal malignancy2.

Like solitary CHRPE, grouped bear-track CHRPE has no associated ocular symptoms or well-established links with other ocular abnormalities. It presents unilaterally, which serves as the key factor in differentiating it from multiple CHRPE, a bilateral presentation which is pathognomonic for FAP.

The term ‘CHRPE’ applied to bilateral pigmented lesions found in FAP is one of optometry’s most infamous misnomers. Histologically, these lesions are different from solitary and bear-track CHRPE, and are thought to represent benign hamartomatous malformations of the RPE. These RPE hamartomas are found in 70-80% of patients presenting with FAP. All patients presenting with bilateral pigmented lesions should be investigated to eliminate the possibility of associated systemic health issues.

People with FAP have an increased risk of developing bowel cancer, and FAP is a result of a mutation in the APC gene. The syndrome is characterised by the development of numerous polyps in the intestine. These are often present by the time patients are in their late teens.

 

REFERENCES

  1. Trichopoulos N1, Augsburger JJ, Schneider S Adenocarcinoma arising from congenital hypertrophy of the retinal pigment epithelium. Graefes Arch Clin Exp Ophthalmol. 2006 Jan;244(1):125-8. Epub 2005 Jun 28.
  2. Shields JA, Shields CL, Shah P, et al. Lack of association between typical congenital hypertrophy of the retinal pigment epithelium and Gardner’s syndrome. 1992;99:1705–1713
  3. Katsonos KH, Syrrou M, Tsianos TV The value of opthalmic examinations in familial adenomatouspolyposis syndrome screening Annals of Gastroenterology 2003, 16(4):287-299
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