Patrick Farley MD (Neuroradiology) and Thomas Bouldin MD
(Neuropathology), UNC, Chapel Hill
Case 1

History: Middle-aged man with no
significant PMH became confused and
disoriented. Head CT showed a brain
mass. He was transferred to UNC.

Imaging:
 Head CT:
○ 2.6-cm left frontal lobe lesion with surrounding edema.
 Brain MRI:
○ Multiple bilateral supra-and infratentorial enhancing lesions.
The largest is located in the left parietal lobe causing 7 mm
of midline shift.
 MR Spectroscopy:
○ Increased choline to creatinine ratio in the region of the left
parietal mass.
 Diffusion tensor imaging:
○ Loss of anisotropy in mass and surrounding tissues.
Ring Enhancing Lesion Diff Dx
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Metastases Parenchymal
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Abscess
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Substantial vasogenic edema for relative size of lesion at corticomedullary junctions
Thin T2 hypointense rim characteristic and central diffusion restriction
Multiple Sclerosis

Enhancement indicates acute demyelination, with minimal mass effect;
periventricular location

Coexistence of enhancing and nonenhancing lesions due to relapsing, remitting
nature of disease
Acute Disseminated Encephalomyelitis (ADEM)

Multifocal white matter and/or basal ganglia lesions

May have with punctate, ring, incomplete ring, or peripheral enhancement
Neurocysticercosis

Ring enhancement seen in colloidal vesicular & granular nodular stages
Less Common Ring Enhancing Diagnoses
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Immunocompromised

Tuberculosis
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Multiple ring-enhancing lesions in HIV+ patient:

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Consider toxoplasmosis, TB, pyogenic/fungal abscess, & lymphoma
Toxoplasmosis is most common opportunistic infection
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Ring enhancement seen in HIV+ patients with lymphoma
MRS: Elevated choline peak
Radiation necrosis may cause multiple enhancing lesions

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Basal Ganglia & gray-white matter junctions
Asymmetric "target sign": Enhancing eccentric nodules within abscess cavity
MRS may differentiate Toxo from lymphoma; NAA & choline usually nearly absent (Toxo)
Lymphoma, Primary CNS
○
○

Caseating TB granulomas often have markedly T2 hypointense centers
Infants, children, & immunocompromised are predisposed. Opportunistic Infection, AIDS
Often difficult to differentiate from recurrent tumor
MRS: No elevated choline. MR perfusion: Hypoperfusion
Multifocal Glioblastoma Multiforme

Seen in malignant transformation of low grade glioma & spread of primary GBM

Subacute Intracerebral Hematomas

Subacute Cerebral Infarctions

Enhancement pattern is ring-like and gyriform
Neuropathology

Photomicrograph of brain biopsy showing necrosis (*), nuclear debris of
degenerating cells (short arrow), and two tissue cysts containing
bradyzoites (long arrow) typical of Toxoplasma gondii. The histologic
changes are consistent with CNS toxoplasmosis.
Toxoplasma gondii

A protozoan and an obligate intracellular parasite

Affects ~30% of the world’s population

Sexual cycle (oocyst stage containing sporozoites) occurs
within feline intestinal tract (definitive host)

Humans get infected by ingesting oocysts (fecal–oral
spread) or tissue cysts (undercooked meat).

After ingesting the organisms (sporozoites in oocysts;
bradyzoites in tissue cysts), the organisms invade the gut
epithelium, differentiate into tachyzoites, and disseminate to
body organs via the blood stream.
Toxoplasma gondii

Tachyzoites invade cells, especially those of CNS, eye, skeletal
muscle, and heart.

When conditions are unfavorable, tachyzoites convert to
bradyzoites and become encysted (tissue cyst) within cells.

Wall of tissue cyst has very low immunogenicity, so that tissue
cysts can persists for very long time.

If tissue cyst ruptures, bradyzoites convert to tachyzoites and
replicate within tissue until controlled by immune response.

Control of infection depends on an interferon-gamma-dependent
cellular immune reaction.

CNS toxoplasmosis has a predilection for the basal ganglia and
gray-white junction
Case 2

Middle-aged man recently s/p left upper lobectomy for
fungal infection. Resected lung specimen also found to
contain a poorly differentiated spindle cell neoplasm.

Several days after surgery, patient was noted to have
rhythmic jerking of his head to the left with intermittent
jerking spells in his right and left arms. Imaging studies
of the head were done.
Imaging

CT:
 Multiple lesions in brain parenchyma with surrounding
edema.

MRI:
 Enhancing masses w/central necrosis and surrounding
vasogenic edema. One lesion demonstrated blood
products compatible with hemorrhage.
Neuropathology
Left panel: Patient died from metastatic cancer. At postmortem examination, a coronal
section of the formalin-fixed brain shows two well-circumscribed metastases. Note the
edema surrounding each metastasis. The dark color of the metastases is due to
associated hemorrhage.
Right panel: Photomicrograph of one of the brain metastases shows a poorly
differentiated, pleomorphic spindle cell neoplasm. Immunohistochemical stains did not
reveal the histogenesis of this neoplasm.
Case 3

Middle-aged man w/personality changes, occasional
left-sided headaches, left-sided pain in teeth, and
left lower extremity pain.

Dentist found no cause for pain and advised him to
go to hospital. A head CT was done and showed a
left temporal mass. MRI of brain confirmed this
finding.

MRI:
 Large enhancing mass in the left temporal
lobe, with solid and cystic components and
mass effect on left temporal lobe.
Neuropathology
Photomicrograph of brain biopsy showing a poorly differentiated, very pleomorphic
glial neoplasm. Several tumor giant cells with huge nuclei are present in this field.
The histologic findings are those of a giant cell glioblastoma, WHO grade IV.
Giant cell glioblastoma

There are two currently recognized variants of glioblastoma—
Giant cell glioblastoma and Gliosarcoma

The mean age at presentation for giant cell glioblastoma is ~41 years.

Giant cell glioblastoma has short clinical course, like “primary”
glioblastoma, but a high frequency of TP53 mutations, like
“secondary” glioblastoma.

Giant cell glioblastoma is usually a circumscribed, firm tumor that
may mimic a metastasis.

Giant cell glioblastoma often arises in the temporal or parietal lobes.
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Giant cell glioblastoma and glioblastoma have a similar prognosis.
Case 4

History:
 7 yo boy with no PMH presents with progressively worsening
HA x 2 weeks, vomiting x 1 today, and lethargy. Had a CT that
showed hydrocephalus and a mass in 3rd ventricle.

MRI:
 Round hypointense lesion in 3rd ventricle and suprasellar
regions with peripheral enhancement and internal septations.
Obstructive hydrocephalus, secondary to mass.
Neuropathology

Photomicrograph of biopsy of tumor showing a squamous epithelium
and the formation of “wet keratin” (*). These histologic features are
typical of an adamantinomatous craniopharyngioma, WHO grade I.
Case 5

History:
 This 23-year-old patient was involved in an altercation and
had a head CT as part of the trauma workup. The CT
revealed a cerebellar mass. MRI confirmed the lesion.

MRI:
 Complex enhancing cerebellar mass with two
components. Inferior component has thicker rim of
enhancement. Superior component demonstrates
numerous internal septa, fluid levels, and low T2 signal
rim, suggesting possible prior hemorrhage.
Neuropathology
Photomicrograph of biopsy showing proliferation of glial cells with mild
atypia and no mitotic figures. Several microcysts are present in this field.
The histologic findings are those of pilocytic astrocytoma, WHO grade I.
Pilocytic Astrocytoma
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Cystic cerebellar mass with enhancing mural nodule
Rare in adults
Hemorrhage is rare
Other Considerations
 Medulloblastoma
○ Hyperdense enhancing mass filling 4th ventricle
 Ependymoma
○ Mass within the 4th ventricle
 Metastasis
 Hemangioblastoma
Case 6
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Man in is late 60s, who has felt unsteady on his
feet for last three months, as though he were
"drunk." He feels he needs to focus on walking
and needs a wider-based gait to feel steady.
 CT: Partially solid and cystic, enhancing mass
lesion; intra-axial in cerebellum.
 MRI: Large, partially cystic mass, with solid
nodular component that demonstrates intense
contrast enhancement.
Neuropathology
Photomicrograph of biopsy showing a proliferation of “stromal cells” with
oval nuclei, mild atypia, and no mitotic figures. Also prominent in the
tumor are multiple blood-filled vascular channels. The histologic findings
are consistent with a hemangioblastoma, WHO grade I.
Hemangioblastoma

Solid and cystic cerebellar tumor in an
adult with enhancing mural nodule
abutting the pia.

25-40% occur in patients with Von
Hippel-Lindau syndrome.

The histogenesis of the “stromal cells” is
not clear.