Retrospective chart review of the use of imaging and biopsy in the diagnosis of optic nerve sheath meningiomas and intra-conal orbital lymphomas at a single institution.

Optic nerve sheath meningiomas (ONSM) and intra-conal orbital lymphomas are common entities on the differential of a retrobulbar optic nerve involving space-occupying lesion. In this study, we compare the pre-surgical diagnosis, based on clinical presentation and neuroimaging, to the surgical pathology results of intra-conal orbital lymphomas and ONSM. This is an IRB approved retrospective chart review of orbital lymphomas and optic nerve sheath meningiomas biopsied by a single surgeon over a 4-year period at a single institution. Pre-surgical diagnosis and surgical pathology were compared. Fifteen cases of orbital lymphoma were identified. Fourteen were excluded based on extra-conal location. The single histologically confirmed intra-conal orbital lymphoma had a pre-surgical diagnosis of ONSM. Four cases of optic nerve sheath meningioma were identified. Three of the 4 cases of histologically confirmed ONSM had a pre-surgical diagnosis of ONSM. One of the 4 had a pre-surgical diagnosis of lymphoma. Diagnosis based on surgical pathology differed from the pre-surgical diagnosis in 2 out of 5 cases showing that clinical diagnosis does not always correlate with histologic diagnosis. Although both diseases are typically managed with radiation therapy, the treatment dosage and systemic disease implications are very different. These findings emphasis the importance of biopsy in the diagnosis of orbital lesions surrounding the optic nerve.