Massive Retinal Gliosis - A Rare Benign Condition Masquerading as a Malignant Intraocular Tumor: A Case Report.

Massive retinal gliosis (MRG) is a rare, benign intraocular condition resulting from reactive glial cells undergoing exaggerated repair phenomenon. A 52-year-old male presented with 6-year history of enlarging mass in the right eye, associated with progressive vision loss and worsening proptosis. He reported history of trauma to that eye secondary to a vehicular crash one year prior. Magnetic resonance imaging (MRI) of the orbits revealed an intraocular lesion with calcifications raising the possibility of a malignant tumor. Enucleation of the right globe was performed and histopathologic examination revealed the entire vitreous cavity and retina replaced by glial cells arranged in interlacing bundles and whorls with foci of calcifications, highly suspicious of MRG. This was further confirmed by a positive, diffuse, and robust cytoplasmic expression of glial fibrillary protein (GFAP). The disease is known to have favorable outcomes as no complications, such as reemergence of the mass, active bleeding, and secondary infection, were observed from the patient during subsequent visits. Distinction of MRG from other intraocular neoplasms is clinically challenging, hence biopsy is necessary. MRG should be considered as a differential diagnosis when encountering intraocular tumors, especially if there is a history of eye trauma. This is the first reported case of MRG in the Philippines.