Gliomas

- name the subtypes

- WHO grades

Astrocytoma

- WHO Grades 2-4

    ~ Grade 1 = pilocystic astrocytoma (peds)

Oligodendroglioma

- WHO grade 2-3

    ~ Grade 2 = well differentiated

    ~ Grade 3 = anaplastic

Ependymoma

- WHO grade 1-3

    ~ Grade 1 = myxopapillary variant

    ~ Grade 2 = well differentiated

    ~ Grade 3 = anaplastic 

4 histological features of gliomas used for WHO grading

- name them

Pleomorphism

Mitotic features

Microvascular proliferation

Necrosis

Astrocytoma (WHO Grade 1)

- juvenile pilocystic astrocytomas only

Astrocytoma (WHO Grade 2 - low grade)

- pleomorphism

Anaplastic astrocytoma (WHO Grade 3)

- pleomorphism + mitosis

Glioblastoma (WHO Grade 4)

- pleomorphism + mitosis + vascular proliferation and/or necrosis

Glioblastoma (Astrocytoma WHO Grade 4)

- age at presentation

- radiographic appearance

- gross appearance

- histological appearance

Age at presentation = 50-70 years

Radiographic findings:

- ring-enhancing lesion

- peritumoral edema

Gross appearance:

- irregular borders and infiltrative appearance

- variegated - foci of hemorrhage and necrosis

Histological appearance:

- highly infiltrative

- mitotic

- pleomorphic

- vascular proliferation and necrosis

Primary vs Secondary Glioblastoma multiforme (GBM)

- age of presentation

- grading at diagnosis

- molecular genetics

- epidemiology

Primary GBM

- older age = ~62 years old

- grading at diagnosis = high grade (4) GBM

- molecular genetics = EGFR amplification and PTEN mutations

- epidemiology = 85% of GBM patients

Secondary GBM

- age at presentation = younger (~45)

- grading at diagnosis = 2-3

- molecular genetics = TP53

- epidemiology = 15-20% of patients

Oligodendroglioma

-WHO grading

-clinical presentation

-radiological findings

-histological findings

-genetic findings

WHO grading:

- Grade 2 = well differentiated; eventually progresses to malignancy

- Grade 3 = anaplastic oligodendroglioma

Clinical presentation:

- long clinical hx of seizures

Radiological findings:

- calcification on CT

Histological findings:

- round nuclei with perinuclear halo = fried eggs

- "chicken wire" vascular pattern and calcification

Genetic findings:

- Deletion of 1p and 19q = better prognosis and response to chemotherapy

Ependymoma

- where is it typically found (children and adults)

- clinical presentation

- histological findings

Typical locations:

- intraventricular mass

- 4th ventricle (common in children)

- spinal cord (adults)

Clinical presentation:

- likely to obstruct CSF flow → noncommunicating hydrocephalus

Histological findings:

- perivascular "pseudorosettes" - cell processes are GFAP+

- "ependymal" true rosettes

Tumors with neuronal differentiation

- name them

Ganglioglioma

Central neurocytoma

Primitive neuroectodermal tumor (PNET) such as medulloblastoma

Ganglioglioma

- classic presentation

- histological findings

Presentation and typical location:

- classical hx of temporal lobe seizures

Histological findings:

- combo of mature and neoplastic neurons

- ganglion cells

- neoplastic glial components

- calcification

Meningioma

- epidemiology

- clinical presentation

- cellular origin

Epidemiology:

- females > males (3:2)

- ~15% of intracranial tumors

- responsible for < 7% of brain tumor deaths

Clinical features:

- symptomology due to compression not infiltration

- slow growing tumor

- usually surgically resectable

- WHO grades 1-3 (don't need to know)

Cellular origin:

- derived from arachnoidal cells of the meninges but have dural attachment

Primary CNS lymphoma

- clinical presentation

- pathology

- treatment

Clinical presentation:

- AIDS, immunocompromised individual, older individuals

Pathology:

- solitary or multiple hemorrhagic, necrotic foci

- Non-Hodgkin, large B-cell type lymphomas

- angiocentric growth

Treatment:

- treat increased ICP with steroids causes dramatic reduction in tumor size making it impossible to biopsy

--> over time becomes less responsive to steroid Rx 

- antibodies useful as well

Metastatic brain lesions

- most common

- location

- radiological findings

Most common:

- lung (30%)

- breast (20%)

- renal cell (10%)

- colon (5%)

Location:

- gray-white junction where microvasculature is well developed

- Middle cerebral artery territory

Radiological findings:

- necrotic centers → ring lesions

- extensive peritumoral edema

Schwannoma

- Typical location = 80% in cerebellopontine angle as part of CN8

- More common in females

- Bilateral Schwannoma found in neurofibromatosis 2

- S100+

- Peripheral nerve sheath tumor

- Diffuse or fusiform enlargement of a peripheral nerve

- Usually benign though 8% of NF1 patients undergo malignant transformation to malignant peripheral nerve sheath tumor (MPNST)

- spindle cells: Schwann and fibroblasts with myxoid background

- S100+

Spinal cord tumors

Intradural/Intramedullary:

- ependymomas most frequent; astrocytoma less common

Extradural, Intradural - extramedullary

- Schwannomas and meningiomas most common in adults

- compress cord and nerve roots, interfere with circulation in cord, radicular pain and myelopathy

Metastatic tumors high in frequency

- usually extradural

- compress cord and roots

- radicular pain and myelopathy