Reactive Retinal Astrocytic Tumor (Focal Nodular Gliosis): A Case Report.

PURPOSE: To report the clinical and histopathological findings of a reactive retinal astrocytic tumor (RRAT) that progressed to massive retinal gliosis. OBSERVATIONS: The patient presented with an elevated, white-yellow retinal mass and extensive retinal exudation in the left eye. Progressive enlargement of the mass and proliferative vitreoretinopathy eventually led to phthisis bulbi and enucleation. Histologically, the mass showed a predominant astrocytic component with intense glial fibrillary acidic protein staining, hyperplasia, fibrous metaplasia, and osseous metaplasia of the retinal pigment epithelium. The Ki-67 proliferative index was <5%, and few scattered vascular channels were observed. CONCLUSIONS AND IMPORTANCE: These findings show that this tumor is the result of a reactive glial process rather than of neoplastic vascular proliferation. Massive retinal gliosis probably represents the advanced stage of RRAT.