Massive Retinal Gliosis Mistaken as a Malignant Intraocular Tumor in Phthisis Bulbi.

Massive retinal gliosis (MRG) is a rare condition of non-neoplastic glial proliferation, which forms massive lesions that fill the eye. MRG is commonly associated with phthisis bulbi (a non-functional eye), congenital anomalies, or malformations. Herein, we report a case of massive retinal gliosis associated with a traumatic phthisis bulbi, which was initially mistaken as a malignant intraocular tumor and confirmed only after an eye enucleation. A 70-year-old woman presented with a protruding ocular mass in her left eye which had slowly grown for a year. She had phthisis bulbi in her left eye due to trauma during her childhood. An orbital CT revealed an intraocular mass lesion with calcifications, raising the possibility of retinoblastoma or other malignant intraocular tumors. Enucleation of the left eye globe was performed. Histopathologic examination revealed exuberant proliferation of the glial cells, metaplastic bone formation, hyalinized vessels, and hyperplasia of the retinal pigment epithelium, confirming the diagnosis of MRG. Although rare, the possibility of MRG should be considered as a differential diagnosis when encountering an intraocular mass lesion, as it can be misdiagnosed as a malignant tumor.