Background: Malignant lymphomas originating primarily in the cavernous sinus have not been histologically verified by any authors. The first reported case to our knowledge of primary cavernous sinus malignant lymphoma, initially diagnosed as benign meningioma and treated by gamma knife radiosurgery, is presented.
Case description: The patient was a 77-year-old man whose initial symptoms were left facial hypesthesia and diplopia on left gaze. During the 21-month follow-up period after gamma knife radiosurgery, no evidence of tumor regrowth was seen in the irradiated area, but an unirradiated mass expanded with invasion of the brain stem. Subsequent surgery provided histologic verification of the diagnosis. Despite successful local tumor control, the patient died due to sepsis 31 months after the onset of symptoms. Autopsy failed to disclose any remaining lymphoma cells either in the primary lesion or anywhere throughout the entire body.
Conclusion: Primary cavernous sinus malignant lymphoma is an extremely rare brain tumor, but it must be considered in the differential diagnosis of an enhanced mass in the cavernous sinus. Stereotactic radiosurgery using the gamma knife technique for intracranial brain tumors, especially in the cavernous sinus, is associated with risk, as was seen in our patient. Our experience points out the pitfalls of gamma knife radiosurgery; it should be performed only after histologic confirmation has been obtained.