[Study on the characteristics of optic nerve meningiomas in medical imageology,histopathology and immunohistochemistry].

OBJECTIVE: To determine the characteristics of optic nerve meningiomas in medical imageology (including CT and MRI), histopathology and immunohistochemical expression of Vimentin, CK, S-100, EMA in tumor cells. METHODS: This was a retrospective study on a serial of clinical cases. Forty-eight cases were collected from the past 21 years at the Department of Ophthalmology, West China Hospital, Sichuan University. All the cases underwent surgery and were confirmed as optic nerve meningiomas by histopathological test, including paraffin imbedded sectioning and HE staining. In addition, all the cases had medical records on CT and 17 cases had MIR scan. Immunohistochemical staining for VIMENTIN, CK, S-100, EMA was performed in the 21 cases. RESULTS: Characteristics of the CT scan include that, in 39 cases, among them 26 cases the tumors filled in the orbit especially at the orbital apex, which led to the disappearance of the black triangle. Three cases showed enlargement and calcification of optic nerve and therefore train track sign was seen. Three cases showed that the masses of optic nerve were close to the globe and another three cases showed that the masses were located in the peripheral orbit. Thirteen of 17 cases MRI disclosed the big orbital tumors and 5 cases could better show tumor extension to optic cross or intracranium. Histopathological tests demonstrated meningothelial or syncytial type in 39 cases, transitional or mixing type in 8 cases, fiber or fibroblast type in 3 cases and vascular type in 2 cases. Immunohistochemistry study verified the positive staining rate of VIMENTIN as 90.5%(21 cases), EMA 66.7%(15 cases), CK 42.8%(9 cases) and S-100 23.8%(5 cases), respectively. CONCLUSIONS: Characteristics of CT and MRI include enlargement and tumor-like expansion of optic nerve. Most of the tumors reach to orbital apex and show uneven density. Calcification may occur in the tumor. The main pathological type of the tumors is meningothelial. Positive immunohistochemiscal staining for VIMENTIN and EMA may be helpful in diagnosis.