Background Osteosarcoma (OS) is the most common primary bone carcinoma. Adulthood most frequent intraocular malignant tumor is choroidal metastasis; however, these are rarely related to sarcomas. There are only two OS-related choroidal metastasis cases reported in the literature, both prior to 1970. Case presentation A 20-year-old man with a history of tibial OS, right leg amputation, and lung and brain metastases, presented with decreased vision in his right eye (OD). Ophthalmic examination revealed a best-corrected visual acuity of hand movements and a large, posterior pole, nodular, subretinal mass, with associated fluid. B-scan revealed a heterogeneous lump, with medium/high reflectivity, and a height-to-base ratio (HBR) of 1-1.2, approximately. Computerized tomography (CT) scan showed a hyperdense and contrast-enhanced mass, while on magnetic resonance imaging (MRI) the lesion appeared T1-isointense and T2-hypointense. Conclusion Choroidal OS metastasis can appear as a pink nodule with high HBR and intralesional hyperreflective deposits. Sudden visual changes in individuals with OS-related systemic metastatic disease should be monitored closely by ophthalmology and oncology jointly.