RETINA QUIZ

Retinal Lesion in a Spy's Eye

by Mark T. Dunbar, O.D


Pigmented lesion along the superior arcade with active leakage.

A 68-year-old white female began noticing blurry vision and waviness inferiorly in her right eye over the past month. She is a semi-retired British intelligence agent and related that the condition became especially problematic while dodging pedestrians during a high-speed chase on the busy streets of Paris. After narrowly escaping with her life, she made an emergency visit to her optometrist as an emergency.

Her best-corrected visual acuities were 20/30 O.D. and 20/20 O.S. Confrontation fields were full to careful finger counting, motility testing was normal and there was no afferent pupillary defect. On Amsler grid testing, she demonstrated a large area of metamorphopsia along the inferior half of the grid that did not extend to fixation. Anterior segment exam was normal.

Early and late hyperfluorescence with active leakage

Dilated fundus exam showed healthy optic nerves with good rim coloration and perfusion O.U. Present in the right eye along the superior arcade was a slightly elevated lesion with an overlying neurosensory detachment that extended inferiorly and stopped just above the macula.

Follow-up at 18 months shows clearing of the fluid.
The ophthalmologist working in the practice was consulted and agreed that a fluorescein angiogram and standardized ultrasound were indicated. A fundus photo appears above and images from the fluorescein angiograms appear below. The ultrasound showed a highly reflective lesion that was approximately 1 mm in thickness. The second fundus photo  is from a follow-up exam approximately 18 months later.

 

 

    Quiz
     1. What is the yellow white material densely scattered throughout lesion?
    a. Drusen.
    b. Exudate.
    c. Dense patches of cotton wool spots.
    d. Medulated nerve fibers.

    2. What is the etiology for the yellow-white material?
    a. Macroarterial aneurysm.
    b. Ischemia.
    c. Choroidal neovascular membrane.
    d. Malignancy.
    e. Congenital.

    3. What is the underlying problem with this patient?
    a. Choroidal nevus.
    b. Choroidal melanoma.
    c. Macroarterial aneurysm.
    d. Eccentric disciform process.

    4. The results of the ultrasound:
    a. Confirm that the lesion is vascular in nature.
    b. Make you highly suspicious of a malignancy.
    c. Provide relief that the lesion is benign.
    d. Confirm your thinking that the patient is just getting too old.

    5. What is the most appropriate treatment?.
    a. Careful observation.
    b. Vascular work-up.
    c. Iodine 125 Plaque radiotherapy.
    d. Laser photocoagulation.

Discussion
The dense yellow-white material spewing out of this lesion is exudate from a choroidal neovascular membrane. The fluorescein angiogram shows a poorly defined neovascular membrane with early leakage and hyperfluorescence that builds in intensity as the angiogram progresses. Late in the angiogram there is active leakage and marked hyperfluorescence.

The important question: Why does she have a choroidal neovascular membrane in this particular location? One possibility would be an eccentric disciform process, which is a rare presentation of macular degeneration that occurs outside the macular area.

However, on careful examination a slightly elevated, pigmented lesion below the exudate, at the level of the RPE, can be seen. An elevated pigmented lesion in the fundus should always arouse suspicion of a malignancy, such as a choroidal melanoma. The most useful diagnostic test is ultrasound, which in this patient showed a 2.25mm x 3.0mm, highly reflective lesion that was 1mm in thickness. These findings are not consistent with a choroidal melanoma, which would show low to medium reflectivity, but are more typical for a choroidal nevus.

Choroidal nevi are developmental tumors that are usually incidental findings discovered during a routine eye examination. Ninety-five percent of choroidal nevi will be flat, slate gray in appearance, and less than 3 disc diameters in size. Occasionally choroidal nevi can have more of a "suspicious" appearance, making it difficult to distinguish between a choroidal melanoma, especially if the nevi are not flat.

There are some clues that may help you in making this distinction when examining a patient with a suspicious pigmented lesion. Lesions less than 3mm in thickness are more likely to be a choroidal nevi. Overlying drusen is a sign of a chronic condition, which indicates the lesion has been present for a significant period of time, and probably represents a choroidal nevus. Other findings indicating the lesion is benign in nature and has been present for some time include RPE atrophy overlying the lesion, intra-retinal pigment migration, fibrosis and choroidal neovascular membranes.

In one retrospective study1 of 23 patients with choroidal neovascularization associated with choroidal nevi, only one patient had documented evidence of growth, and that was detected after 17 years of no growth. An actively growing choroidal melanoma does not have time to develop these chronic changes over the lesion. Orange pigment within the lesion, on the other hand, represents "lipofuscin" and is considered to be more of a malignant change. This should make you suspicious that the lesion is, in fact, a choroidal melanoma. Serous fluid in the absence of a choroidal neovascular membrane can be seen in either choroidal nevi and choroidal melanomas, however, seen in conjunction with lipofuscin, would indicate the lesion is actively growing.

Ultimately the best way to determine if the lesion is melanoma or nevus is to take a photograph and document growth of the lesion over time. Choroidal nevi will rarely show any significant growth.

Treatment is indicated for the neovascular membrane if visual acuity becomes affected. In our patient, visual acuity ultimately dropped to 20/70 before she had laser photocoagulation. Following the procedure, visual acuity improved back to 20/25. The second fundus photograph of this patient is after laser treatment. There is clear evidence of the choroidal nevus and clearing of the exudate. The patient resumed her busy career in semi-retirement, working for British intelligence.

1. Callanan DG, Lewis ML, et al. Choroidal neovascularization associated with choroidal nevi. Arch Ophthalmol 1993;111:789-794.

Answers: 1.b; 2.c; 3. a; 4. c; 5.d.
 

 

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