Presented by Georgia Kamboj, MD, PhD
Brief Case Description
A 67-year-old white man was referred for an enlarging choroidal lesion.
Figure 1: Wide-field color photo of the left eye one year prior to presentation. Note the amelanotic lesion inferiorly with pigment clumping over the surface. The dark spot just superior to the lesion is an artifact created by a floater.
Figure 2:Wide-field color photo of the left eye. Note the amelanotic lesion inferiorly. Compared to the lesion 1 year earlier as shown in Figure 1, it has enlarged. The dark spot at the posterior border is an artifact.
The patient presented with progressive blurring of the central vision in his left eye over a 1-month period. He denied flashes/floaters, metamorphopsia, and photophobia. A choroidal lesion in the left eye was noted and found to have increased in size compared with fundus photographs taken 1 year prior (Figure 1). His past ocular history was otherwise significant for an epiretinal membrane in the right eye that had last been evaluated by a retina specialist 3 years prior.
Past medical history was significant for stage 4 prostate cancer and cutaneous melanoma that was excised with clear margins and no known spread. Family history is noncontributory. Review of systems was otherwise negative.
The patient’s best corrected Snellen visual acuity measured 20/20 in the right eye (OD) and 20/63 in the left eye (OS). Intraocular pressure was normal in both eyes. Anterior segment exam of the right and left eyes revealed nuclear sclerotic cataracts. Posterior segment exam of the right eye was significant for an epiretinal membrane. The left fundus was notable for a large (14 mm x 14 mm), irregular shaped, amelanotic lesion with hyperpigmented areas, and extended inferiorly from the inferior edge of the macula (Figure 2). The lesion had increased in size compared with fundus photographs taken by the referring doctor 1 year earlier (Figure 1). Fundus autofluorescence showed the lesion to be mostly hypoautoflurescent, but with increased areas of autofluorescence near the margins (Figure 3). Optical coherence tomography (OCT) of the right eye showed an epiretinal membrane (Figure 4A). OCT of the left eye showed an irregularly thickened choroidal mass involving the inferior macula and extending to the fovea, with associated sub-retinal fluid (Figure 4B). B-scan of the left eye revealed an echogenic choroidal mass, 1.8 mm in height, with a shallow retinal detachment overlying the tumor surface (Figure 5).
Figure 3A: SD-OCT of the right eye. A mild epiretinal membrane is present.
Figure 3B: SD-OCT of the left eye through the lesion. Note the subretinal fluid overlying a thickened choroidal lesion.
Figure 4: Wide-field color fundus autofluorescence of the left eye. Note the large lesion inferiorly that is mostly hypoautofluorescent, with increased autofluorescence mostly along the enlarging margin.
Figure 5: B-scan ultrasound of the lesion. Shallow subretinal fluid is present over the surface. The lesion measures about 1.8mm thick.
The patient had a diagnosis of metastatic castration-resistant prostate cancer (mCRPC) with known metastases to the lymphatics and bone. He was taking abiraterone and oral prednisone for the last 3 years. PET CT performed 2 months prior to his ocular evaluation showed stable disease.
Diagnosis and Patient Course
The enlarging, amelanotic lesion is characteristic of choroidal metastasis. The hyperpigmented areas indicate chronicity. Prostate is the most likely primary in this patient with mCRPC. The patient is planned to undergo proton beam radiation given that there are no other new or progressing lesions on PET CT and there is known tumor resistance to hormone therapy.
Prostate cancer is known to have a long natural history with different treatment options as the disease progresses through different states (metastatic versus non-metastatic, castrate versus non-castrate).1 Disease progression despite castrate testosterone levels is associated with transition into a castration-resistant state.1 The mainstay of treatment in patients with mCRPC includes systemic treatment with anti-androgen (including Abiraterone) and chemotherapy agents.1 Treatment options for those who continue to have active metastases despite Abiraterone treatment include the addition of further systemic agents, or targeted radiotherapy if the lesion is amenable.
Choroidal metastases from prostate are relatively rare, accounting for only 2% of all uveal metastases.2 In those with uveal metastases, the primary tumor most commonly originates in the breast (37%), followed by lung (27%), kidney (4%), gastrointestinal tract (4%), cutaneous melanoma (2%), lung carcinoid (2%) and prostate (2%).2 The primary site is unknown in 29% of male patients presenting with uveal metastases.3 In 67% of cases, the primary tumor is diagnosed prior to the detection of uveal metastases.4 There is a mean interval of 5.2 years between diagnosis of the primary tumor and development of uveal metastases.4 The overall 5-year survival of patients presenting with uveal metastases is 24%, and this increases marginally to 31% when considering only those presenting with uveal metastases from the prostate.2
Metastases to the choroid most commonly present as yellow (86%), orange (8%) or brown (4%) lesions.2 Subretinal fluid is present in 72% of cases.2 Vision is impaired when subretinal fluid extends to involve the macula. Multimodal imaging is useful in confirming the diagnosis of choroidal metastasis. Characteristic findings on OCT include choriocapillaris compression (93%), a “lumpy bumpy” anterior contour (64%), and subretinal ﬂuid (79%).5 On ultrasonography, most tumors are dome-shaped or placoid echodense masses.6 On ﬂuorescein angiography, choroidal metastases demonstrate early hypoﬂuorescence with late staining and multifocal retinal pigment epithelial pinpoint leaks.6 Hypocyanescence with minimal late staining is classic on indocyanine green angiography, and this differs from choroidal melanoma which commonly demonstrates hypercyanescence.7 In cases where the diagnosis of uveal metastasis is unclear or the primary is unknown, fine-needle aspiration biopsy (FNAB) can be helpful.6
Management options include radiotherapy (external beam (EBRT), proton beam or plaque), systemic chemotherapy and photodynamic therapy (PDT).6 In patients with solitary choroidal metastases, plaque radiotherapy has been shown to achieve tumor control in 94% of cases.8 In addition, 57% of eyes treated with EBRT have been shown to regain some vision.9 PDT is able to accomplish tumor control in 78% of cases.5 Choroidal metastases in patients with mCRPC have been reported to respond well to local radiation in published case reports.10