MULTIMODAL IMAGING OF CRB1 RETINITIS PIGMENTOSA WITH A PERIPHERAL RETINAL TUMOR.

Purpose: To report the multimodal imaging findings of a patient with gene- crumbs 1 -associated retinitis pigmentosa (RP) characterized by preservation of para-arteriolar retinal pigment epithelium and a peripheral retinal tumor.

Methods: A 27-year-old woman was referred to our center because of progressive decreased vision in both eyes with a diagnosis of gene- crumbs 1 -associated RP. Fundus examination was remarkable for attenuated retinal vessels and bone spicule migration that was bilateral and symmetric. In addition, an elevated yellow-white mass with dilated retinal vessels was noted in the superotemporal midperiphery of the retina in the left eye without any associated exudation.

Results: Diffuse retinal pigment epithelium mottling was present but spared the area along the retinal arterioles. Swept-source optical coherence tomography showed diffuse outer retinal atrophy. Optical coherence tomography angiography of the peripheral lesion illustrated extensive vascularity and a possible retinal feeder vessel communicating with the tumor at its inferior margin. The phenotype of the lesion showed overlap with a vasoproliferative tumor or an astrocytic hamartoma. Over a period of 5 years of follow-up, the peripheral tumor was unchanged. No significant progression of the peripheral retinal degeneration was evidenced by autofluorescent imaging over this time period although the central acuity continued to decrease.

Conclusion: Gene- crumbs 1 -associated RP may be characterized by preservation of the para-arteriolar retinal pigment epithelium and slow progression and may also feature a benign peripheral retinal tumor.