Case Author(s): J. Philip Moyers, M.D. and Farrokh Dehdashti, M.D. , 5/17/96 . Rating: #D4, #Q5
Diagnosis: Gliomatosis Cerebri
Brief history:
This patient presented in
September 1995 with worsening headaches and has
had progressive changes in the white matter on serial
MRI examinations.
Images:
Axial images from 18-fluorodeoxyglucose (FDG) brain scintigraphy
View main image(pt) in a separate image viewer
View second image(mr).
Axial T2 weighted image at level of thalamus
View third image(mr).
Axial T2 image just above ventiricles
Full history/Diagnosis is available below
Diagnosis: Gliomatosis Cerebri
Full history:
After presenting with headaches
in September, 1995, the patient underwent MR
examination which demonstrated diffuse nonspecific
white matter changes. On serial MRI examination,
these changes were demonstrated to have progressed.
The patient underwent thalamic biopsy which
demonstrated nonspecific changes. PET imaging of
the brain was requested to evaluate for areas of most
active disease to further direct future biopsy. The
patient underwent biopsy of the left parietal lobe as
well as subcortical parietal white matter, which
demonstrated gliomatosis cerebri.
Radiopharmaceutical:
11.0 mCi F-18
fluorodeoxyglucose (FDG) i.v.
Findings:
The left and right hemispheric gray
matter appears thinned and compressed correlating
with the white matter expansion and sulcal
effacement identified on MRI. Hypometabolism
identified diffusely in the left hemisphere relative to
the right with more focal areas of hypometabolism
demonstrated in the left parietal lobe as well as the
left thalamus. MRI scan demonstrates nonspecific
areas of increased signal on T-2 weighted images in
these regions.
Discussion:
Gliomatosis cerebri is often a
difficult diagnosis to make due to the diffuse nature of
the disease and lack of specific MRI changes. On this
examination, a PET study was performed to evaluate
for areas of focally decreased activity which may yield
positive biopsy results. Gliomatosis cerebri is a
diffuse overgrowth of the central nervous system with
neoplastic glia. Early neuroradiologic investigations,
namely cerebral angiography and
pneumocephalography, demonstrated only minor
nonspecific changes in the presence of a devastating
clinical condition. CT also often does not demonstrate
specific morphologic changes in this condition and
demyelinating conditions often cause confusion. MRI
typically demonstrates high signal on T2-weighted
images. A recent case report with FDG-PET
demonstrated extensive hypometabolism of superficial
and deep gray matter, consistent with diffuse
infiltration. Detection of white matter involvement by
slow-growing infiltrative tumors is a difficult task
with FDG-PET because of the poor contrast between
normal hypometabolic white matter and the glucose
hypometabolism typical of low-grade tumors. C-11
methionine with PET also has been utilized with this
condition. However, the findings with this radiotracer
are nonspecific and benign conditions cannot be
differentiated from malignant conditions as increased
uptake can be present in both high and low grade
gliomas.
References:
1) Nevin S. Giomatosis cerebri. Brain 1938;61:170-
191.
2) Di Chiro G. Positron emission tomography using
Followup:
Biopsy of left parietal lobe (in the
region of focal hypometabolism) revealed infiltrative
astrocytic neoplasm. The patient is currently
undergoing evaluation prior to chemotherapy.
Differential Diagnosis List
Benign
processes (e.g. vascular related) and low-grade
neoplasm.
ACR Codes and Keywords:
References and General Discussion of PET Tumor Imaging Studies (Anatomic field:Skull and Contents, Category:Neoplasm, Neoplastic-like condition)
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Case number: pt011
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