Purpose: To report the ophthalmological and serological characteristics of the newly identified paraneoplastic visual loss syndrome in patients with recent history of basal cell carcinoma (BCC) and positive for autoantibodies (AAbs), recognizing retinal, retinal pigment epithelium (RPE) and/or optic nerve (ON) antigens.

Methods: Twenty-eight cases of BARN were identified (14F/14M, 48-87 yo). Serologies included immunoblotting for anti-retinal, anti-RPE AAbs, and anti-ON AAbs and retinal immunohistochemistry (IHC). A BCC tissue sample was available for IHC. We report summary data for all subjects and report on 8 subjects examined in detail with visual fields (VFs), full-field flash electroretinograms (ffERG), pattern visual evoked potentials (PVEPs) and various imaging methods.

Results: Multiple anti-retinal, anti-RPE (incuding anti-RPE65, which is found also in the human epidermis), and anti-ON AAbs were detected. Most cases had bilateral but variable and asymmetricvisual acuity and VF loss, and abnormal ffERGs. In the 8 subjects examined in detail, ffERG abnormalities varied from mild cone dysfunction to severe rod and cone compromise. RPE loss wasseen clinically and by fundus autofluorescence, ranging from punctate patterns to large atrophic RPE patches. All cases with PVEP abnormalities and delays (5/8), which were independent of acuity, had anti-ON AAbs, labeled retinal ganglion cell (RGC) and/or retinal nerve fiber layer (RNFL) on IHC, and typically exhibited RNFL changes on optical coherence tomography (OCT). The ellipsoid zone (EZ) was spared foveally in all cases, but there was often overt retinal degeneration peripherally and EZ loss in the perimacular region. In the case for which BCC tissue was available for IHC, there was marked staining of the cancer cells by the patient’s AAbs.

Conclusions: The BARN association had not been previously reported. Our study show a strong association with the observed AAbs, and especially the anti-RPE65 AAbs, strongly suggesting that BARN is a novel paraneoplastic entity triggered by an autoimmune reaction initiated by BCC antigens. Both retinal and optic nerve compromise, mostly intraretinally at the RGC/RNFL level, existed in numerous cases and the latter was often the main acuity loss determinant. History of BCC should be sought out in patients with suspected paraneoplastic vision loss.