Autofluorescence and histological findings in cancer‐associated retinopathy caused by small cell lung carcinoma

Abstract Purpose: To present clinical and histological features of lipofuscin autofluorescence of the retinal pigment epithelium‐RPE in a patient with cancer associated retinopathy‐CAR,a paraneoplastic syndrome caused by small cell lung carcinoma‐SCLC. Methods: 78 year‐old man with SCLC suffered bilateral blindness.Autofluorescence imaging was done using Topcon fundus camera and,post mortem,light microscopy with autofluorescence and electron microscopy of the retina were done.Retinal photography,fluorescein angiography,electrophysiology and auto‐antibody assay were also performed in vivo. Results: Autofluorescence imaging showed diffuse hyperfluorescence suggesting accumulation of lipofuscin in the RPE,and few hypofluorescent atrophic regions due to age‐related changes.Autofluorescence microscopy showed lipofuscin accumulation in the RPE and electron microscopy revealed predominance of lipofuscin granules over melanin pigment.Western blot analysis was positive for anti‐recoverin antibodies.The electroretinogram and visual evoked potentials were non‐detectable.Histology showed complete loss of photoreceptor layer and outer nuclear layer as well as decrease in number of nuclei in the inner nuclear layer with no inflammation.Fluorescein angiography revealed severe atherosclerosis with no occlusions and patchy atrophic changes with no leakage. Conclusions: In CAR,in vivo autofluorescence imaging showed diffuse hyperfluorescence suggesting increased phagocytic activity and lipofuscin accumulation due to autophagy of the destroyed photoreceptors in the RPE by autoantibody‐induced apoptosis,which was confirmed ex vivo by autofluorescence of lipofuscin in histological sections and by electron microscopy.