Starts with fundus photo of a rather large choroidal melanoma
- Presented with floaters and photopsias
- Ultrasound shows dome shaped mass of low to medium reflectivity
Uses this to then talk about cases that are not so obvious, rare, and can kill your patient. Likely most ophthalmologists only see 1 or 2 cases in their whole career. There is no single diagnostic test.
Shields Classification fo "To Find Small Ocular Melanoma"
- T Thickness
- F Subretinal fluid
- S Symptoms
- O Orange pigment
- M Margins <3mm from disc
- Use this system WITH CAUTION as you can still miss some choroidal melanomas as if follow over time, you may see growth into tumor
Goes on to give a couple of case examples where the above mnemonic failed.
Differential diagnosis for the cases she presented includes:
- Choroidal haemangioma
- Large choroidal neovascularization
- Choroidal adenoma
And here is more information I retrieved for this posting in the form of a citation to a Carol Shields Article from 1980 that still seems to hold up today despite newer technologies that might have developed since then:Two large studies from the Armed Forces Institute of Pathology (AFIP) have listed the various lesions which may clinically resemble malignant melanomas of the posterior uvea (pseudomelanomas). The studies from the AFIP were based upon histologic examination of eyes which were enucleated. The present study reports on 400 consecutive patients who were referred but who proved, by clinical evaluation, rather than by enucleation, to have a pseudomelanoma. Although about 40 different conditions were found to simulate melanoma, the more commonly encountered ones included suspicious choroidal nevus (26.5%), disciform degeneration (12.5%), peripheral disciform degeneration (11%), congenital hypertrophy of the retinal pigment epithelium (9.5%), and choroidal hemangioma (8%). The authors believe that this series provides the clinician with a differential diagnosis for posterior uveal melanomas which accurately reflects the clinical problem confronting ophthalmologists today.