A 64-year-old man, diagnosed with a retinal detachment of his left eye, was sent to our hospital to evaluate vitreoretinal surgery. Left eye best-corrected visual acuity was hand motion. Fundus examination showed a voluminous slightly pigmented choroidal neoformation with secondary retinal detachment. Ultrasonography revealed a large hyperechogenic choroidal mass with retinal detachment, initial choroidal excavation, and low-to-medium internal reflectivity. The clinical-instrumental aspects of the lesion suggested a primary malignancy. The patient underwent chest radiography, which showed a large mass located in the right lung. Contrast-enhanced computed tomography of chest and abdomen showed a voluminous lung lesion, another gross lesion of the liver, and other abdominal localizations. The patient underwent biopsies of the pulmonary and hepatic lesions and both samples showed an epithelial malignancy with neuroendocrine differentiation, compatible with metastatic small cell lung cancer. The patient's clinical condition declined within one month from presentation. In the interim, a contrast-enhanced brain computed tomography documented the presence of cerebellar metastases. The patient was admitted to the oncology department and started chemotherapy and supportive care, but unfortunately he died during the course of the treatment, 5 months after his initial presentation. This case is peculiar both for the unusual presentation of small cell lung cancer and for the morphological appearance of the choroidal lesion that suggested a primary tumor.