Tumours of the Nervous System Flashcards
In the general population the incidence of metastatic cerebral tumour is ________
much higher than that of a primary cerebral neoplasm
What is the common appearance of metastatic brain tumours?
multiple well-delineated spherical nodules that are randomly distributed throughout the brain
List some categories of brain tumours?
- Gliomas
- Meningeal tumours
- Tumours of Nerve Sheath
- Tumours of Neuronal cell types
- Germ cell tumours
- Pituitary gland tumours/ sella lesions
- Haemopoeitic/ lymphomas
List a few characteristics of all gliomas?
They are usually found in the hemispheres, they spread by direct invasion and they rarely metastasise
2 main types of glioma?
Astrocytic or oligodendroglial tumours
What are meningiomas thought to arise from and where are they most commonly found?
Thought to arise from arachnoid granulations so are most commonly found adjacent to venous sinuses
Meningiomas are ____ growing and essentially _______
slow
benign
Two types of tumours of the nerve sheath?
Schwannomas
Neurofibromas
Where are schwannomas derived from?
From the schwann cells surrounding axons
Most common type of schwannoma and location?
Vestibular schwannoma of the CNVIII in the cerebellopontine angle
What symptoms may a vestibular schwannoma cause?
Progressive sensorineural hearing loss, tinnitus and imbalance on ONE SIDE
Schwannomas are ______ but can be difficult to remove because _______
benign
grows around adjacent structures and has an irregular surface
What are neurofibromas derived from?
These are derived from endoneurium which is a layer of delicate connective tissue around the myelin sheath of each nerve fibre in the PNS
Neurofibromas may be solitary or ________ and can affect peripheral nerves over a _______ They can undergo _____ transformation
multiple
wide area or a single group of nerves
malignant
Fully differentiated neurones can neither multiply or ____1_____ Tumours of this type are therefore derived from ____2_____ and seen in _____3______
1) give rise to neoplasms
2) primitive nerve precursors (blast cells)
3) infancy and childhood before completion of differentiation
Medulloblastoma is a primitive nerve cell tumour arising from the _____
cerebellum
Retinoblastoma is a primitive nerve cell tumour arising from the _______
retina
Neuroblastoma and ganglioneuroma is a primitive nerve cell tumour arising from _______
- These are tumours that arise from sympathetic ganglia
* In ganglioneuromas the tumour is derived from blast cells but as the tumour grows the neurons actually mature
How do germ cell tumours usually arise?
Occasionally arise in midline structures and derived from embryologically displaced germ cells
(people can have these misplaced germ cells in their brain their whole life and would only find out if a tumour arose from them)