Neuroepithelial Tumors: Astrocytoma

by Carlo Raj, MD

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    00:01 Our topic here is neuroepithelial tumor.

    00:05 We’ll begin with where are we in terms of organization.

    00:08 Primary metastasis.

    00:10 This is primary CNS tumor.

    00:13 Under primary CNS tumor, we’re looking at neuroepithelial tumor.

    00:18 The classification of neuroepithelial tumor will be your astrocytic or astrocytomas.

    00:25 Let’s take a look.

    00:27 Definition: tumor derived from, as you can imagine, astrocytes.

    00:31 And you think of these as being glial cells and how often have you come across a description, a reading, or a narration or, let’s say, a CPC, a pathologic conference in which you’re sitting around and you hear the term glioma, right? Well, this is what we’re referring to.

    00:51 So the fact that you have an astrocytoma, please be aware that anatomically, these cells, glial cells, and at some point, these would then be referred to as being gliomas.

    01:04 The types: We’ll take a look at low-grade, referred to as being fibrillary type of astrocytoma.

    01:11 Anaplastic is never a good thing.

    01:14 Glioblastoma multiforme, we’ll be spending time with this one in greater detail.

    01:18 And the reason for that is it is one of the most common, unfortunate brain tumors that occurs in adults, but really, it could be seen across the spectrum.

    01:29 Then we have an astrocytoma that occurs almost exclusively in children or very commonly in children and this then referring to your pilocytic astrocytoma.

    01:41 And you’ll be focusing upon the -cytic and I’ll tell you why in a bit and then you can have your what’s known as your pleomorphic xanthoastrocytoma.

    01:56 Let’s take a look at astrocytoma further.

    01:58 And under here, 87% of adult primary brain tumors will be an astrocytoma.

    02:04 That’s how important these gliomas are.

    02:07 80% of adult primary brain tumor, you want to put yourself into the category of astrocytomas.

    02:15 Let it be your fibrillary, anaplastic, or glioblastoma multiforme.

    02:21 Usually arises in the cerebral hemisphere as you can imagine because we’re not dealing with our meninges.

    02:27 Usually presents with as you can imagine, once again, the brain parenchyma, so therefore perhaps focal neurologic deficit.

    02:34 Maybe there’s headache and maybe there’s new onset seizures.

    02:38 This is an important point.

    02:39 Pay attention to the clinical presentation.

    02:41 Understand why these would be seen because we’re referring to the brain parenchyma.

    02:46 Pathogenesis: Inactivation of p53.

    02:50 As soon as you have p53 that has been knocked out, there is really nothing that is modulating or regulating your cell cycle.

    02:57 And so therefore, the cell is allowed to remain within the cell cycle forever, and so therefore may then result in increased proliferation.

    03:06 Please note: Over-expression of platelet derived growth factor A or alpha.

    03:11 PDGF, memorize that please for astrocytoma specifically, a.k.a. gliomas, and here we have adult.

    03:19 You’ll notice here that the astrocytoma that’s missing in adult primary brain tumor is which one? Pilocytic.

    03:31 Let’s talk about the gross examination of your brain tumors.

    03:36 Fibrillary astrocytoma: Poorly defined, gray, infiltrative tumor that expands and distorts the normal brain.

    03:44 Fibrillary.

    03:46 The one that you want to pay attention to here as well is glioblastoma multiforme.

    03:50 Areas of firm and white or soft and yellow areas representing your areas of necrosis.

    03:57 And what’s dangerous about glioblastoma is even when you are trying to surgically correct it, there’s every possibility that these will then come back And in addition, these particular neoplastic cells will then seed -- seed, in terms of spread -- and by seeding, we mean it is then going to pop into adjacent structures, maybe perhaps even your cerebrospinal fluid.

    04:24 Microscopically, fibrillary, mild to moderate increase in number of glial cell nuclei.

    04:31 That should make perfect sense.

    04:33 This is an absolute malignancy.

    04:35 And this is an astrocytic origin.

    04:38 And so therefore, we expect the nuclear to cytoplasmic ratio to be quite high.

    04:43 Extreme activity in the nucleus.

    04:46 And we have nuclear pleomorphism, intervening what’s known as feltwork and make sure that you memorize glial fibrillary astrocytic processes.

    04:56 GFAP.

    04:58 Your positive astrocytic cell processes.

    05:01 GFAP.

    05:03 So you’ve got a couple of things here to memorize.

    05:05 Earlier, I told you about pathogenesis and it could be the suppression of your p53.

    05:10 Or number 2, your PDGF alpha.

    05:13 and then please make sure under astrocytoma, you keep in mind GFAP.

    05:18 Glial fibrillary astrocytic processes.

    05:22 With the anaplastic, what does that mean to you? Complete chaos that’s taking place within the nuclei.

    05:28 So increased cellularity and nuclear pleomorphism beyond belief, marked mitotic activity.

    05:34 Anaplastic, complete, complete poor prognosis.

    05:38 And then we have a glioblastoma multiforme.

    05:41 You have a greater nuclear pleomorphism.

    05:43 I would highly recommend that you know in greater detail the microscopic feature of glioblastoma.

    05:49 Increased mitotic figure with necrosis and vascular and we have perhaps endothelial cell proliferation, representing your angiogenesis.

    05:59 Glioblastoma multiforme.

    About the Lecture

    The lecture Neuroepithelial Tumors: Astrocytoma by Carlo Raj, MD is from the course Tumors of the CNS.

    Author of lecture Neuroepithelial Tumors: Astrocytoma

     Carlo Raj, MD

    Carlo Raj, MD

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