Meningioma: Introduction

00:00 So how do we think about meningiomas? Well, they're the most common primary brain tumor worldwide.

00:06 They make up 30% of all primary brain tumors.

00:09 So we should know about them.

00:11 The majority are histologically benign.

00:13 World Health Organization, WHO grade 1 tumors.

00:18 And why do they occur? We don't know.

00:21 They arise from the cells, the arachnoid cells that lie within the meninges that cover the brain.

00:28 And we'll talk about some of the risk factors for meningiomas.

00:32 These tumors are typically benign, slow growing tumors.

00:36 The median age at diagnosis is around 66 years, and the risk progressively increases as we age.

00:43 So the older the patient is, the more likely we are to see a meningioma.

00:48 Turns out that women are twice as likely as men to development meningioma.

00:52 So we think about these in women.

00:53 There's a two to one, female to male predominance.

00:57 And there are some important but rare risk factors.

01:00 Prior ionizing radiation to the brains of patients who have received radiation as a child, and certain genetic syndromes like neurofibromatosis type 2, which we'll talk about in a subsequent lecture.

01:14 I'd like this table to help us think about meningiomas, and how they fit into other benign brain tumors that occur in the brain.

01:22 We see here in the columns, the percentage of all nervous system tumors that are meningiomas. It's about 40%.

01:29 The percentage of all benign brain tumors that are meningiomas, they make up 50% of the benign brain tumors that we see where they occur, which is the meninges, which is not surprising, and the neurologic manifestations headache, focal neurologic deficits, seizures, and occasionally altered mental status.

01:46 Let's see how that compares to pituitary tumors.

01:49 The second most common benign tumor of the brain, which accounts for 16% of nervous system tumors, about a quarter of benign brain tumors and occurs in the pituitary, and typically presents with headache like meningiomas, but often bitemporal hemianopia, type of vision loss that we'll discuss in a subsequent lecture.

02:09 And then the third most common tumor is the schwannoma, 8% of all brain tumors, 12% of benign tumors, and it occurs in that cerebellopontine angle.

02:17 Remember at the CP angle, we say, AMEN because we see acoustic neuromas, meningiomas, epidermoid cysts, and neuromas of the facial nerve.