Optic nerve glioma: A great mimicker
A 27-year-old male presented with progressive, painless loss of vision in right eye, associated with vomiting and headache for one and a half months, without accompanying loss of consciousness or fever. He had a history of seizures 4 years back, for which he was on antiepileptic drugs. On clinical examination, there was no perception of light in the right eye while left eye vision was normal. Computed tomography (CT) scan revealed a contrast enhancing mass arising from planum sphenoidale with mass effect []. The adjacent pituitary fossa and cavernous sinus were normal.\nPerioperative findings showed a grayish pink, nonsuckable tumor firmly adherent to the right optic nerve and expanding it. The tumor was also attached to basal dura and falx. Debulking surgery was performed. A clinical impression of an intradural, optic nerve sheath meningioma was made.\nHistopathological examination of the excised tumor revealed a moderately cellular glial tumor intermixed with extensive reactive proliferation of arachnoid cells. The tumor cells were present in a fibrillary background and exhibited minimal nuclear pleomorphism. No mitosis, necrosis or micro-vascular proliferation was noted. Adjacent to the tumor, there was marked fibroblastic and arachnoid cell proliferation with chondroid as well as chordoid differentiation along with myxoid change and dense collagenisation. The sharply outlined tumor was reticulin poor while the adjacent reactive areas were rich in reticulin fibers. On immunohistochemistry using Dako antibody kit, the tumor cells expressed glial fibrillary acid protein (GFAP). [] Epithelial membrane antigen (EMA) highlighted the reactive arachnoid cells. The chondroid areas were positive for S-100. A final diagnosis of optic glioma displaying exuberant arachnoid proliferation with cartilaginous metaplasia was made.\nPostoperatively, there was no improvement in the vision. Recurrence of tumor was noted after a period of four months and debulking surgery was repeated. Histopathological examination confirmed the presence of glioma (grade I) having similar morphology as the previous tumor displaying extensive fibro-mesenchymal proliferation of the meninges. The patient is on regular follow-up, however, there is still no improvement in the vision.