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INTRAVENTRICULAR EPIDERMOID-MRI
Epidermoids
represent 0.2-1% of all intracranial masses. They arise from inclusion
of epithelial remnants trapped during 3-5 weeks of fetal life (remember
that choroid plexus are also formed from invagination of ectodermal
tissues).
Intraventricular epidermoids are more in 4th ventricle followed by lateral ventricles.
More common in middle age; very rare in children
If ruptured, aseptic meningitis occurs.
Long
T1 and T2 are due to keratin in solid crystalline state. Epidermoids
have restricted ADC and complex FLAIR signal, unlike arachnoid cysts. FINDINGS
An
expansive intraventricular lesion in lateral ventricle, iso-intense on
T1-weighted image and hypo-intense on T2-weighted image with few cystic
areas, demonstrating restricted diffusion suggestive of
INTRAVENTRICULAR EPIDERMOID. Differential diagnosis includes
Intraventricular Neurocytoma and Oligodendrogliomas but calcification
is hallmark for their diagnosis. Case by- Teleradiology Providers
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Optic
nerve glioma (also known as optic pathway glioma) is the most common
primary neoplasm of the optic nerve. In 66% of NF-1 patients with optic
nerve glioma, the growth involves the intraorbital optic nerve. In the
absence of NF-1, the optic chiasm is most commonly involved, as is,
less often, the intraorbital optic nerve. Optic nerve glioma may
involve various portions of the retrobulbar visual pathway, including
the optic nerve, chiasm, tracts, and radiations. Malignant lesions can
invade the hypothalamus, basal ganglia, and internal capsule directly,
or they may spread to the leptomeninges or subpial surfaces. On
T1-weighted images, optic nerve gliomas are usually isointense to the
cortex and hypointense to white matter. Invariably, the lesions are
hypointense to orbital fat. On T2-weighted images, lesions demonstrate
a mixed appearance that is isointense to hyperintense relative to white
matter and the cortex. Following contrast administration, intense
enhancement is common.
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Case submitted by Dr Rishu Sangal, PG Radiology.Pilocytic astrocytomas are well-circumscribed but unencapsulated mass. They represent only 5 - 10% of all cerebral gliomas but one third of pediatric glial neoplasms. Cerebellar asrocytomas are the most common posterior fossa tumor in this age-group. They are tumours of children and young adults with peak incidence at age 10. On NECT scans pilocytic astrocytomas typically are round or oval sharply demarcated marginated hypo or iso-dense masses. Contrast enhancement is variable with some enhancing solidly while others have a small heterogenously enhancing mural nodule. Most cerebellar pilocytic astrocytomas are cystic and therefore appear hypo or isointense on T1 weighted images and hyperintense on T2 weighted scans. Mural nodules and solid tumours enhance strongly but heterogenously. Obstructive hydrocephalus may occur relatively early and may become severe if licated in the vermis or fourth ventricle.
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These are post gadolinium MRI images of the Optic chiasmatic-hypothalamic glioma extending along the posterior optic nerves and posterior optic pathways.
Dr.Sumer K Sethi, MD
Sr Consultant Radiologist ,VIMHANS and CEO-Teleradiology Providers
Editor-in-chief, The Internet Journal of Radiology
Director, DAMS (Delhi Academy of Medical Sciences)
Labels: bowel cancer, Brain tumour, dynamic MRI, Teleradiology
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Here is a case of epidermoid tumour in the suprasellar location and it appeared bright on DWI.
Dr.Sumer K Sethi, MD
Sr Consultant Radiologist ,VIMHANS and CEO-Teleradiology Providers
Editor-in-chief, The Internet Journal of Radiology
Director, DAMS (Delhi Academy of Medical Sciences)
Labels: Brain tumour, CT, epidermoid, Sellar Masses
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