Essential Topics in Neuropathology

Okay, so here's the scenario.

You're a neurology resident, and you're studying for some big boards-type exam.  FrontalCortex.com has hundreds and hundreds of neuropathology images and stuff, but you want to focus on the high-yield neuropathology.  What are the topics you'd really, really want to review before the test?

Here are some topics that are definitely testable, because they're clinically important and have really recognizable pathology that every resident should know:

Tumors:

• glioblastoma
• oligodendroglioma 
• meningiomas

• Nemaline rod myopathy
• Central core myopathy
• Inflammatory Myopathies
  

Peds:

• neurofibromatosis
• lissencephaly
• polymicrogyria

Other Stuff:

• Lewy Bodies
• Neurofibrillary tangles
• Amyloid plaques
• Freidreich ataxia
  
• PKAN
• Carbon Monoxide poisoning
• MS plaques
• Cowdry A bodies
  

Please add your list.  This will help us prioritize the topics to develop first in the online course.

We'll also add links from this page to the relevant material. 

PKAN = Pantothenate kinase-associated neurodegeneration.

This is the ailment formerly known as Hallervorden-Spatz syndrome.  Since Hallervorden and Spatz were involved in Nazi atrocities, they don't get to keep the disease anymore.

Ingy -

Thanks for the excellent question.

Admittedly, oligodendroglioma and dysembryoplastic neuroepithelial tumor (DNT) look a lot alike, and you might not be able to tell the difference between them if all you saw was one slide.  For examination purposes, therefore, they're unlikely to ask you to differentiate the two based on appearance alone.

For real-life purposes, there are ways to differentiate the two, and some of these depend on the history. 

They are both classified as glial / glioneuronal tumors.  They both tend to present with seizures as the initial symptom.  Both tumors may or may not enhance on imaging studies. On specific immunohistochemical stains, both tend to be GFAP negative and S-100 protein positive.

DNT is rare.  The typical history is that of a patient presenting as a child, or before the age of 20. The mean age of onset is at 9 years.  It is associated with cortical dysplasia, and generally arises from the cortex.  It classically, but not always, arises from the temporal lobe.  It is typically multinodular.  On imaging, this nodularity is often apparent, and the tumor may cause molding of the overlying skull.  The finding of a "specific glioneuronal component" - mature-appearing neurons floating within a collection of oligodendrioglia-like cells - is supposed to be diagnostic.  DNT is a Grade I tumor that is curable with surgical resection.

Oligodendrogliomas are more common, with an annual incidence of 0.6 per 100,000 people.  It can present at any age, but is rare in children, is more common in adults, and has a peak in the 40's.  On imaging, calcifications are very common.  More than half arise in the frontal lobes.  It tends to arise in the white matter.  Perineuronal satellitosis can sometimes be in oligodendrogliomas, but is not seen in DNT.  Oligodendrogliomas are Grade II or III tumors, and the prognosis is less favorable than that of DNT.

Hope this helps.  If anyone has anything else to add to this, please do.

REFERENCES:

Prayson, R.A., and Goldblum, J.R. (Eds.) (2005). Neuropathology. Elsevier Churchill Livingstone, Philadelphia. (ISBN:0443066582)

Tatke, M., Sharma, A., and Malhotra, V. (1998). "Dysembryoplastic neuroepithelial tumour." Childs Nerv Syst, 14(7) 293-6. (PMID:9726578)

O'Brien, D.F., Farrell, M., Delanty, N., Traunecker, H., Perrin, R., Smyth, M.D., and Park, T.S. (2007). "The Children's Cancer and Leukaemia Group guidelines for the diagnosis and management of dysembryoplastic neuroepithelial tumours." Br J Neurosurg, 21(6) 539-49. (PMID:18071981)

Engelhard, H.H., Stelea, A., and Cochran, E.J. (2002). "Oligodendroglioma: pathology and molecular biology." Surg Neurol, 58(2) 111-7; discussion 117. (PMID:12453646)

Prayson, R.A., and Cohen, M.L. (2000).  Practical Differential Diagnosis in Surgical Neuropathology.  Humana Press, Totowa, N.J. (ISBN:0896038173)

One of the original authors of the DNT paper has gone so far to say that a CORTICALLY-BASED tumor in a young patient presenting with seizures is a DNT till proved otherwise.

In the specific glioneuronal element of DNT, the neurons appear to float free in lots of extracellular mucopolysaccharide matrix. In oligos, most of the clearness in INTRAcellular, and the cells tend to surround the neurons preferentially.

In adults, 1p deletion may help separate the two, as deletion is not seen in DNT. In kids, the problem is that oligos also only rarely show 1p deletion.

Intraoperatively, there may be confusion with ganglioglioma/piloid glioma in areas not showing glioneuronal element. As all are grade I, this is usually not a huge problem. Also, GG/PA usually show cyst/mural nodule, and DNT shows more prominent intracortical component.

Thanks for asking,

M

they sate this is a feature usually seen in lower grade neoplasms, such as pleomorphic xanthoastrocytom or ganglioglioma, true? How can you tell the difference on path?

2. Not a path questions, but EEG, i heard you had a good mnemonia for the cornea and telling which way the pt is facing and if they are looking up and down, true?

How can you tell the difference on path?

 ---difference between what?

 M

I can't rememeber what I was asking the difference of, hehehe,

thank you for the answers :)

Hoping gliageek can field this one, please:

I'm reading about laminar necrosis in anoxia/hypoxia, which is defined as damage to cortical layers III and V, specifically "extensive eosinophilic degeneration and death, with sparing of the other neocortical layers."

When the neuroradiologist reads the MRI of a patient with presumed (post-infectious) cerebritis as having "laminar necrosis," does this imply the same specific pathology, i.e. loss of these 2 cortical layers?  Is this pattern not just from anoxia?  Do neuroradiologists and neuropathologists mean the same thing when they say "laminar necrosis"?

Regards,

Suzanne 

Suzanne,

Laminar necrosis is the selective loss of the metabolically specialized, and therefore more oxygen/blood flow dependent, neurons which occupy layers III, V, and VI.

I've not heard of post-infectious cerebritis, so I can't help you with this. Sounds like too much time spent in a dark room ;]

Sorry about that,

M

What is the difference between a psudorosette and a homer-wright?

What is the difference between onion bulb and a psamoma body? bc it all looks like vegtables to me. 

Going back to the original descriptions, any rosette without a lumen is a pseudorosette. However, these days when we say "pseudorosette", we mean perivascular psuedorosette, most often seen in ependymomas. Homer Wright (peudo) rosettes contain a center composed of primitive neurites and indicate neuroblastic differentiation in PNETs.

Both onion bulbs and psammoma bodies are concentrically laminated, but the former is composed of Schwann cells in non-neoplastic endoneurium, and the latter is composed of tumor cells, most often (in our speciality) in meningiomas.