November 2010
Janica Walden, MD (Neuroradiology Fellow) and Thomas Bouldin, MD
(Neuropathologist)
Case # 1
 Young adult male with PMH significant for NF-1
 Had been followed over the past few years for a tectal
glioma with secondary ventriculomegaly
 The lesion and ventriculomegaly had been stable.
 The patient had been doing well until he died
suddenly.
Imaging
 Brain MRI performed four months before death, when
compared with prior MRIs, showed
 Stable tectal mass, most compatible with a glioma
 Stable dilatation of the lateral and third ventricles
 Stable enhancing lesions within the left basal ganglia
and right frontal lobe white matter
 Stable abnormal T2 hyperintense signal in the cerebellar
vermis.
Clinical Course
 Although the patient had been doing well, he died
suddenly.
 Postmortem MRI of the brain was performed in order
to gain more insight as to the cause of death.
Postmortem Imaging-MRI
 The tectal glioma did not change in size or
demonstrate any evidence of hemorrhage between the
last premortem MRI and the postmortem MRI.
 There is development of lateral and third ventricular
hydrocephalus between the two studies. The
suggestion of trans-ependymal flow of CSF in the
postmortem study may be an artifact.
 There is evidence of aqueductal obstruction .
Sagittal postmortem T1WI shows obstruction of
cerebral aqueduct (arrow) by tumor.
Left panel: Section through formalin-fixed, postmortem specimen of midbrain and upper
pons. A gray, gelatinous neoplasm is present in the midbrain in the region of the
cerebral aqueduct. No cerebral aqueduct is identifiable in this section macroscopically.
Right panel: The tectal glioma has histologic features of a pilocytic astrocytoma.
Usual Causes of Sudden Death
Related to Intracranial Pathology
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Epilepsy (sudden unexplained death in epilepsy)
Intracerebral hemorrhage
Spontaneous subarachnoid hemorrhage
Subdural hematoma
Epidural hematoma
Bacterial Meningitis
Brain tumor
Data from Black M, and Graham DI.
Sudden unexplained death in adults caused by
intracranial pathology. J Clin Pathol 55:44–50,
2002.
Tectal Glioma
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Expands tectum & obstructs aqueduct
T2 hyperintense mass, may or may not enhance
Tectal glioma: Most indolent, often only need CSF diversion
Often associated with NF-1
 Focal areas of signal intensity in white matter & deep gray
matter; typically involve globus pallidus
 May involve brainstem
 80% 5-year progression free survival
 Progression or dissemination is extremely rare.
Tectal Glioma: MRI
 High signal T2; minority isointense
 Expands tectum; obstructs aqueduct early
 Remains focal: Tectum/tegmental; (+/-) cerebral
peduncles, thalami
 FLAIR: High signal
 T1WI C+: Variable enhancement
 T2* GRE: Tectal: Hazy calcification, may extend up
crura to thalami
Case #2
 40 year-old male with 4-month history of blurry
vision in his left eye
 Initially evaluated by an ophthalmologist, with MRI
of brain performed at an outside facility
 MRI revealed extra-orbital mass behind the left eye.
 The patient was referred to a neurosurgeon.
Imaging
 MRI showed an extra-axial, dural-based mass along
the left sphenoid wing, most consistent with a
meningioma.
 The mass surrounded the ICA.
 There was enhancement along the left optic nerve,
possibly reflecting extension of the mass or a dural
reaction.
Clinical Course
 Given the patient’s deteriorating vision in his left eye,
surgical resection was recommended in order to
preserve vision. A left pterional craniotomy for
decompression of the left optic nerve and for biopsy of
the lesion were performed.
 Pathology was consistent with neurosarcoidosis.
 Post-operatively, patient had improved vision in left eye.
 Rheumatology was consulted for further treatment.
Photomicrograph of a histologic section from the biopsy of the intracranial mass
shows granulomatous inflammation with several multinucleated giant cells (arrows).
Special stains were negative for mycobacteria and fungi. The histologic changes
are consistent with sarcoidosis.
Sarcoidosis
 Etiology remains unknown.
 CNS is involved in 5% (clinical) to 27% (autopsy) of cases.
 10-20 per 100,000 in North America
 Most common symptom: CN deficit(s), most often facial
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nerve palsy
Onset in 3rd-4th decades
Gender: M:F = 2:1
African-American: Caucasian-American = 10:1
Often indolent disease, with up to 50% asymptomatic
Neurosarcoidosis
 Multisystem inflammatory disease characterized by
noncaseating epithelioid-cell granulomas
 Best diagnostic clue: Solitary or multifocal CNS
mass(es) plus an abnormal chest radiograph
 50% have periventricular T2 hyperintense lesions
 Infiltrates perivascular (Virchow-Robin) spaces of brain
 May cause a small vessel vasculitis
Neurosarcoidosis: MRI
 Wide spectrum of MRI enhancement patterns
 Slightly > 1/3 have multiple parenchymal lesions
 Slightly > 1/3 have leptomeningeal involvement,
nodular and/or diffuse
 10% solitary intra-axial mass
 5-10% hypothalamus, infundibular thickening
 5% solitary dural-based, extra-axial mass
 Other: Vasculitis or ependymal enhancement
 DDx when dural based: meningioma
Neurosarcoidosis: MRI
 T2WI Lacunar infarcts (brainstem, basal ganglia)
 Hypointense material within subarachnoid
space/sulci, focally or diffuse
 Hypointense dural lesion(s)
 FLAIR ≈ 50% have periventricular T2 hyperintense
lesions
 Hyperintense vasogenic edema 2° to
 Infiltration of perivascular (Virchow-Robin) spaces
 May cause a small-vessel vasculitis.
Case #3
 10 year-old child with intractable seizures who was
previously healthy until recent onset of generalized
tonic-clonic seizures and petit-mal seizures
 Managed on anticonvulsants until 3 weeks prior to
admission when child began to have worsening
seizures and gait instability
 EEG showed persistent epileptiform activity, localized
to the right hemisphere, with highest amplitude in
temporal and parietal regions.
Imaging
 MRI showed:
 Atrophy and abnormal T2 signal within right
hippocampus, suggesting right mesial temporal sclerosis
 Areas of abnormal increased T2/FLAIR signal are within
the cortex and subcortical white matter of the posterior
right parietal lobe, right frontal lobe, and right occipital
lobe. Differential Dx includes post-ictal changes and
encephalitis.
Histologic sections of cerebral cortex from brain biopsy.
Left panel: In center of photomicrograph is a cluster of cells forming a “microglial nodule.”
Right panel: Chronic inflammatory cells surround a blood vessel in the cerebral cortex.
Microglial nodules and perivascular chronic inflammation are hallmarks of encephalitis.
Rasmussen Encephalitis
 Chronic, progressive, relentless, unilateral
inflammation of brain of uncertain etiology
 Characterized by hemispheric volume loss and
difficult to control focal seizure activity
 50% preceded by inflammatory episode
 Usually begins in childhood (6-8 years of age)
 Refractory to antiepileptic medications
 Unilateral progressive cortical atrophy
Rasmussen Encephalitis: MRI
 T1WI: Blurring of cortical ribbon during early swelling;
T2WI Early focal swelling of gyri
 Gray, underlying white matter mildly hyperintense
 +/- Basal ganglia, hippocampi involved
 Late: Atrophy of involved cerebral hemisphere or lobe.
 FLAIR: small areas of hyperintensity that progressively
increase over time
 Late: Atrophic, encephalomalacic/gliotic residual brain.
 MRS: ↓ N-acetyl-aspartate (NAA) and choline; ↑ myoinositol, and ↑ glutamine/glutamate
Case # 4
 60 year-old female with history of breast lymphoma
diagnosed two years ago
 Status post chemotherapy and radiation.
 Now presents with progressive weakness, unsteadiness,
intermittent confusion, and right arm tremor.
Imaging Findings
 Enhancing left parietal lesion, concerning for
metastatic disease
 Abnormal signal in the left basal ganglia with
expansion of the left caudate nucleus and lentiform
nucleus; peripheral hyperintensity and central
hypointensity on T2WI; no enhancement
 Differential diagnosis includes lymphoma
Photomicrograph of histologic section from brain biopsy shows poorly differentiated
neoplasm. Immunohistochemical stains confirmed that this is a diffuse large B-cell
lymphoma. The primary breast lymphoma was also a diffuse large B-cell lymphoma.
Metastatic CNS Lymphoma
 Secondary spread of lymphoma to CNS is usually in
the form of leptomeningeal infiltrates.
 Parenchymal lesions, when present, usually result from
secondary involvement from the leptomeninges.
 Via infiltration of pervascular spaces
 Poor prognosis
 Periventricular dissemination is rare.
Metastatic CNS Lymphoma: MRI
 T1WI: Single or multiple iso-or hypointense lesions
 T2WI: Homogeneously iso-or hypointense to cortex
 FLAIR: nonsuppression of CSF in sulci with
leptomeningeal involvement
 Diffusely enhances if dural mass; may see
leptomeningeal enhancement
Case # 5
 3 year-old child presented with a 3-week history of
nausea and vomiting as well as headaches of
increasing frequency and intensity.
 CT scan revealed an intraventricular mass within the
4th ventricle and associated ventriculomegaly.
Imaging
 MRI of the brain showed a 5.9 cm x 2.5 cm x 2.5 cm,
partially cystic, enhancing mass expanding the 4th
ventricle and extending inferiorly through the
foramina of Magendie and Monroe.
 Adjacent mass effect on brainstem and cerebellum
 Increased perfusion within the mass
 Given imaging characteristics, ependymoma was
favored diagnosis.
Photomicrograph of a histologic section from the biopsy of the tumor shows a
glioma with prominent perivascular pseudorosettes. Pseudorosettes are a
characteristic histologic finding in ependymoma.
Ependymoma
 Slow-growing tumor of ependymal cells
 Third most common posterior fossa tumor in children
(after pilocytic astrocytoma and medulloblastoma)
 20-30% of intramedullary spinal tumors in children
 DDx: Medulloblastoma and cerebellar pilocytic
astrocytoma
 Gross total resection plus radiation therapy correlates
with improved survival.
Ependymoma: Imaging Findings
 Soft or "plastic" tumor squeezes out through 4th
ventricle foramina into cisterns.
 2/3rd infratentorial, 4th ventricle
 1/3rd supratentorial, majority periventricular white
matter
 Calcification is common (50%); +/- cysts, hemorrhage