Clinical Neurosciences conference

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Patrick Farley MD (Neuroradiology) and Thomas
Bouldin MD (Neuropathology), UNC, Chapel Hill
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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.

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• 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.

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Ring Enhancing Lesion Diff Dx

• Metastases Parenchymal
• Substantial vasogenic edema for relative size of
  lesion at corticomedullary junctions
• Abscess
• 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

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Less Common Ring Enhancing Diagnoses

• Immunocompromised
• Tuberculosis
• Caseating TB granulomas often have markedly T2
  hypointense centers
• Infants, children, immunocompromised are
  predisposed. Opportunistic Infection, AIDS
• Multiple ring-enhancing lesions in HIV patient
• Consider toxoplasmosis, TB, pyogenic/fungal
  abscess, lymphoma
• Toxoplasmosis is most common opportunistic
  infection
• 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
• Ring enhancement seen in HIV patients with
  lymphoma
• MRS Elevated choline peak
• Radiation necrosis may cause multiple enhancing
  lesions
• 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

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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.
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Toxoplasma gondii

• A protozoan and an obligate intracellular
  parasite
• Affects 30 of the worlds population
• Sexual cycle (oocyst stage containing
  sporozoites) occurs within feline intestinal
  tract (definitive host)
• Humans get infected by ingesting oocysts
  (fecaloral 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.

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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

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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.

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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.

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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.
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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.

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• MRI
• Large enhancing mass in the left temporal lobe,
  with solid and cystic components and mass effect
  on left temporal lobe.

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Neuropathology
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.
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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.
• Giant cell glioblastoma and glioblastoma have a
  similar prognosis.

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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.

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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.
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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.
  

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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.
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Pilocytic Astrocytoma

• 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

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Case 6

• 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.

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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.
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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.