This document discusses different types of brain cysts and tumors. It begins by explaining that brain cysts are not truly brain tumors as they do not arise from brain tissue, and lists the main types as arachnoid, colloid, dermoid, and epidermoid cysts. It then provides details on the locations and characteristics of each cyst type. The document further discusses benign brain tumors including meningiomas, pituitary tumors, and various low and high grade gliomas. It includes CT and MRI images illustrating examples of each tumor type discussed.
Presentation1.pptx, brain film reading, lecture 11.
1. Dr/ ABD ALLAH NAZEER. MD.
Brain film reading, Lecture 11.
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10. Brain cysts located in the brain are not truly “brain tumors” because
they do not arise from the brain tissue itself. Although they tend to be
(benign noncancerous), they are sometimes found in parts of the brain
that control vital functions.
There are four main types of cysts found in the brain:
Arachnoid Cyst (also called Leptomeningeal Cyst): An enlarged, fluid-filled
area of the subarachnoid space that occurs in both adults and children.
Colloid Cyst: Although scientists are not sure of the definitive cause of
colloid cysts, most agree that these cysts begin during embryonic
development of the central nervous system. Malignant forms are
unknown.
Dermoid Cyst: These cysts most likely form during the early weeks of fetal
development even though symptoms may not be noticed until years later.
They are usually benign.
Epidermoid Cyst (also called Epidermoid Tumor): Often referred to as
epidermoid tumors. Likely form during the early weeks of fetal
development even though the symptoms may not be noticed until
decades later.
11. Location
Cysts can appear in a variety of locations within the brain.
Arachnoid Cysts appear in the subarachnoid space (between the
arachnoid and pia mater layers of the meninges).
Colloid Cysts are typically attached to the roof of the third ventricle
and the choroid plexus.
Dermoid Cysts, though rarely found in the brain, are usually located
at the lower back portion of the brain (the posterior fossa) in older
adults and in the lower end of the spine in older children and young
adults.
Epidermoid Cysts tend to be located in the area where the top part
of the brain meets the brain stem.
Arachnoid Cysts are enlarged, fluid-filled areas between layers of
the covering of the brain.
Colloid Cysts tend to contain a thick, gel-like substance called
colloid.
Dermoid and Epidermoid Cysts are tumor-like spheres.
23. Meningiomas are the most common extra-axial tumours of the
central nervous system. They are a non-glial neoplasm that originates
from the arachnoid cap cells of the meninges. Meningiomas have
characteristic imaging findings although there are many variants. They
are typically benign with a low recurrence rate but rarely can be
malignant.
85-90% supratentorial
45% parasagittal, convexities
15-20% sphenoid ridge
10% olfactory groove/planum sphenoidale
5-10% juxta-sellar
5-10% infratentorial
<5% miscellaneous intracranial
intraventricular meningioma (choroid plexus)
optic nerve meningioma
pineal gland
spinal: especially thoracic (see spinal meningioma)
<1% "extra dural”
24. CT is often the first modality employed to investigate neurological signs or
symptoms, and often is the modality which detects an incidental lesion:
60% slightly hyperdense to normal brain
20-30% have some calcification
72% brightly and homogeneously contrast enhance , less frequent in
malignant or cystic variants
hyperostosis
typical for meningiomas that abut the base of skull S
MR signal characteristics include:
T1: isointense: ~60-90%
somewhat hypointense: 10-40% compared to grey matter
T1 C+ (Gd): usually intense and homogenous enhancement
T2: isointense: ~50%
hyperintense: 35-40%
usually correlates with soft textures and hypervascular tumours
very hyperintense lesions may represent the microcystic variant
hypointense: 10-15% compared to grey matter
DWI: atypical and malignant subtypes may show greater than expected
restricted diffusion although recent work suggests that this is not useful in
prospectively predicting histological grade
31. Axial T1-weighted spin-echo MR image of the brain with intravenous gadolinium
enhancement shows dural tail (arrow) attached to a typical meningioma (arrowhead).
35. Other primary tumors, including skull base
Chondroma
Chordoma
Sarcoma
Gliosarcoma
Chondrosarcoma
Rhabdomyosarcoma
Primary Central Nervous System
Lymphoma (PCNSL)
Metastatic brain tumors and carcinomatous
meningitis
63. A glioma is a type of brain tumour that grows from glial cells.
Glial cells support nerve cells with energy and nutrients and help
maintain the blood-brain barrier.
Grade 1-pilocytic astrocytoma: Typically occurs in children in
cerebellum, brainstem and occasionally at the cerebral
hemispheres. It can occur in adults but less commonly. They slow
growing and relatively benign.
Grade 11-low grade glioma: They typically occur in young
adult(20-50y). And most found in the cerebral hemispheres. Some
grade 11 glioma evolve into more aggressive tumours(Grade 111
or IV).
Grade 111-Malignant glioma: Includes anaplastic astrocytoma,
anaplastic oligodendroglioma and anaplastic mixed
oligoastrocytoma.
Grade IV-Glioblastoma multiforme(GBM): GBM is the most
aggressive and most common primary brain tumour. It usually
spread quickly and invade other part of the brain.