A 62-year-old female patient presented to our clinic complaining of a 2 month history of shimmering photopsias and floaters. An ocular examination, fluorescein angiography, and electrophysiological testing were obtained that suggested either an inflammatory retinal vasculitis or a paraneoplastic syndrome. Melanoma-associated retinopathy was highly suspected despite the absence of previous history for cutaneous melanoma since an electronegative scotopic ERG was recorded on standard flash electroretinography. Additional investigations revealed the presence of a primary breast tumor with secondary lung and pancreatic metastasis that led to the diagnosis of cancer-associated retinopathy. The patient received chemotherapy and 4 months after the initial presentation her visual complaints but also her retinal function showed marked improvement. Cancer-associated retinopathy needs to be considered in patients presenting with retinal vasculitis and electrophysiological testing can tailor the approach in these cases.