Clinical, electrophysiologic and serologic evidence of cancer associated retinopathy preceding a diagnosis of breast cancer.

We report the case of a woman in her 50s who presented headaches, blurred vision, diplopia and loss of peripheral vision. She was treated for normal tension glaucoma based on optic nerve cupping prior to the development of diplopia. Records demonstrated visual field constriction over 4 months despite well-controlled intraocular pressures. Examination revealed decreased visual acuity and visual field constriction. The multifocal electroretinogram was abnormal. After a thorough review of her medical and family history, a concern for cancer-associated retinopathy developed. Blood samples were positive for antiretinal antibodies against 23 kDA and 46 kDA proteins. Cancer screening was recommended as the aetiology for retinopathy was unknown and revealed a left breast lump. Following lumpectomy with adjuvant chemoradiation, her visual acuity normalised and visual field defects completely resolved. This case serves to provide an example that distant systemic symptoms may be a manifestation of the underlying malignancy and the importance of clinical suspicion with prompt evaluation.