0513 - Tumours of the CNS Flashcards
What is a single unique feature of CNS neoplasms?
They don’t metastasize outside CNS even when malignant - so need a separate definition of benign and malignant. Instead it kills by compression of vital functions (loss of function) or raised intracranial pressure.
Where are Neurons, Oligodendrocytes, and Ependymal cells (and their respective tumours) found?
Neurons - Grey Matter
Only oligos - White Matter
Ependymal cells - Near ventricles
What proportion of CNS tumours are primary vs metastasis?
25% Primary
75% Metastases
What are some presenting complaints of brain tumours?
Headache Personality changes/psychosis Seizures High intracranial pressure Premature puberty Raised prolactin (brainstem compression) Sudden Death (haemorrhage, coning)
How is malignancy determined with brain tumours? (KEY EXAM CONCEPT)
Not based on metastases, based on micro appearance. WHO Grading.
A - Atypia (nasty nuclei)
M - Mitoses (even 1 is bad)
E - Endothelial Proliferation (occurs near the tumour)
N - Necrosis (= bad)
Outline the WHO grading system of astrocytomas
Grade 1 - Circumscribed, mild increase in cellularity, can be resected. Won’t grow back, grade stable.
Grade 2 - Moderate increase in cellularity, but margins poorly defined or diffuse. May grow back, grade unstable.
Grade 3 - Increased cellularity, moderate pleomorphism and mitosis. Worse than 2.
Grade 4 - Very marked pleomorphism, microvascular proliferation and/or palisading necrosis. The worst.
Briefly outline Astrocytoma
80% of all adult primaries and found in cerebral hemispheres. >40 generally.
Present with seizures, headaches, and focal deficits related to site.
Named according to grade.
What are the different names of astrocytoma according to grading?
1 - Pilocytic astrocytoma
2 - Diffuse astrocytoma
3 - Anaplastic astrocytoma
4 - Glioblastoma multiforme
What are the different types of Astrocytoma?
Diffuse/fibrillary astrocytoma (most common) Pilocytic Astrocytoma (children and young adults) - best one to have Glioblastoma Multiforme (most aggressive, older adults)
Outline Pilocytic Astrocytoma
Most common in cerebellum. Affects young children.
Grade 1, slow growing, good prognosis with surgery only.
Piloid gliosis (reactive astrocytes (scar) around tumour) and eosinophilic granular bodies.
What are the most important prognostic factors for Astrocytoma?
Age - inversely proportional to survival time
Tumour grade - but it can get worse
Any necrosis or incomplete resection is very bad.
Prognosis - 1-2 years.
Outline Oligodendroglioma
5-15% of gliomas
Most common >40
Slow growing, progress over several years.
How can you tell histologically that it’s an oligodendroglioma
Delicate ‘chicken wire’ vessels around in stroma.
Cells look like fried eggs - round nuclei and surrounding halo.
What is the most important factor in Oligodendroglioma prognosis?
1p and 19q deletion is diagnostic of the category.
If you don’t have it, probably not an oligo, but it will be refractory to treatment.
Outline Ependymoma
3-19% of gliomas. Occurs in adults and children
Arise from lining of ventricular system and spinal cord.
Present with symptoms relating to CSF obstruction. CSF dissemination is common.
Histology - makes canals (rosettes), with nuclei away from the lumen)
