A Small Meningioma with Extensive Peritumoral Brain Edema: A Case Report.

Meningioma is the second most common brain tumor. The extent of peritumoral brain edema (PTBE) is one of the important prognostic factors in patients with meningioma. A 55-year-old female patient suffering from a progressive severe headache and mild left hemiparesis was referred to the Department of Neurosurgery, Rasool Akram Hospital (Tehran, Iran). The preoperative imaging revealed a 2×2 cm solid extra-axial mass with bright enhancement at the outer third of the right sphenoid wing. In addition, there was a disproportionately extensive peritumoral brain edema in the right cerebral hemisphere that even involved the right internal capsule. The patient was operated through the right pterional approach and the mass was totally resected. Twenty-one days after surgery, the brain CT scan surprisingly showed only mild frontal edema and the patient was asymptomatic 1 year after the surgical treatment. According to the literature, the size and extension of the PTBE are correlated with the prognosis of meningioma. A larger edema is associated with a larger tumor, higher grade, and a more invasive meningioma with a higher recurrence rate. Our patient had a very large hemispheric PTBE which was disproportionate to the small size of the meningioma and the tumor had not directly invaded the adjacent brain tissue. We believe that the visible compression of the tumor on major veins of the Sylvian fissure was the reason for the PTBE in our patient. The presence of a large PTBE concomitant with a meningioma does not necessarily indicate a poor prognosis. Hence, we recommend a preoperative venogram to be performed in such patients.