Intravascular large B-cell lymphoma is a rare and aggressive lymphoma with a dismal prognosis. Synchronous intravascular large B-cell lymphoma within meningioma has not previously been documented. We report a case of a 73-year-old woman of Asian descent who presented with fever of unknown origin with generalized weakness. CT scan and MRI of the head revealed a dural-based mass lesion consistent with meningioma in the left frontal cerebral convexity. Surgery was performed to remove the tumor and histopathology showed a meningioma within which was a synchronous intravascular large B-cell lymphoma. The hematology and oncology services were consulted and palliative treatment was initiated due to the patient's poor Eastern Cooperative Oncology Group performance status. The patient died within 30 days post-surgery. To the best of our knowledge, this case represents the first report of synchronous intravascular large B-cell lymphoma within a meningioma.