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.


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.


11.0 mCi F-18 fluorodeoxyglucose (FDG) i.v.


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.


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


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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