In a recent report to the nation on the status of cancer in America, it was documented that the incidence and death rates from all cancers combined have decreased significantly. Systemic cancers can metastasize to the eye, the most common of which being breast and lung cancer. The decreasing cancer rates could impact the frequency of ocular metastasis. Metastases to the eye can involve the choroid (88%), iris (9%), or ciliary body (2%), and rarely the retina (<1%). Intraocular metastases most commonly originate from primary cancers in the breast (47%), lung (21%), gastrointestinal tract (4%), kidney (2%), skin (melanoma) (2%), prostate gland (2%), and other sites (4%). Most metastases are often unilateral (76%) and fewer are bilateral (24%). Patient prognosis is poor, and those with metastatic skin melanoma or lung carcinoma typically show poorest survival.
Several conditions can simulate choroidal metastasis including amelanotic nevus, amelanotic melanoma, hemangioma, osteoma, posterior scleritis, retinitis and choroiditis, rhegmatogenous retinal detachment, Harada disease, uveal effusion syndrome, and central serous chorioretinopathy. A detailed history is often helpful in making the differentiation, but the ophthalmoscopic differences are also important.
94.1.1 Common Symptoms
Can be asymptomatic or might experience painless blurred vision, photopsia, floaters, visual field loss, or low-grade ocular pain. Often there is a history of previous systemic cancer, but in approximately 25% of cases, the patient is unaware of underlying cancer.
94.1.2 Exam Findings
Intraocular metastases show a strong tendency to involve choroid, less commonly affect the iris and ciliary body, and rarely involve the retina or optic disc. Metastases can occur in more than one ocular location; most choroidal metastases show multifocality and/or bilaterality (▶ Fig. 94.1, ▶ Fig. 94.2). In an analysis of 520 eyes with uveal metastases, the mean number of tumors per eye was 1.6. In that large analysis, the tumor demonstrated 1 site (71%), 2 sites (12%), and 3 or more sites (17%), up to a maximum number of 13 sites in one eye.
Choroidal metastasis characteristically appears as a homogeneous, creamy-yellow placoid lesion in the postequatorial region. Most metastases produce a serous detachment of the retina and alterations in the retinal pigment epithelium (RPE). When the detachment is extensive, dramatic shifting of the subretinal fluid can be demonstrated with movements of the patient’s head. The RPE changes can be marked, appearing as well-delineated clumps of lipofuscin on the surface of the tumor.
Retinal metastasis often appears with inflammatory-like features along the inner retina and with overlying vitreous seeding (▶ Fig. 94.3). Commonly, the diagnosis is not suspected as the tumor appears like inflammation or infection.
Fig. 94.1 Multifocality of choroidal metastasis. Fundus photography documenting (a) solitary, (b) bifocal, (c) trifocal, and (d) hidden choroidal metastasis.
Fig. 94.2 Bilateral multifocal choroidal metastasis from lung cancer. Montage fundus photography demonstrating multifocal lesions in the (a) right and (b) left eye.
Fig. 94.3 Intraocular metastatic sites. Photographic images of metastatic tumors to the (a) iris, (b) optic disc, and (c) retina in three different patients.
94.2 Key Diagnostic Tests and Findings
94.2.1 Optical Coherence Tomography
Optical coherence tomography (OCT) can easily detect related subretinal fluid, retinal edema, and RPE changes associated with choroidal metastases. Choroidal metastasis demonstrates a “lumpy bumpy” surface, in contrast to choroidal melanoma and hemangioma that appear smooth (▶ Fig. 94.4, ▶ Fig. 94.5). Enhanced depth imaging spectral-domain OCT (SD-OCT) and swept source OCT provide greater details of the choroidal features of these tumors.
Fig. 94.4 Multimodal imaging of breast cancer metastasis. (a) Fundus photograph demonstrates a creamy-yellow deep lesion. (b) Fundus autofluorescence with hyper-autofluorescence of lipofuscin within the retinal pigment epithelium. (c) B-scan ultrasonography demonstrates elevation. (d) Optical coherence tomography demonstrates lumpy bumpy surface with subretinal fluid and loss of choroidal vasculature.