Gliomatosis cerebri is a rare and aggressive glial tumor that diffusely infiltrates at least three cerebral lobes. Although removed as a separate entity in the WHO 2016 classification, this diffuse infiltrative growth pattern is still recognized clinically and radiologically. Its characteristic feature is disproportionately extensive T2/FLAIR hyperintensity with relatively preserved brain architecture — mass effect is minimal relative to lesion extent. Enhancement is typically absent or minimal. It is now considered as an infiltrative growth pattern of diffuse astrocytoma, oligodendroglioma, or glioblastoma.
Age Range
30-60
Peak Age
45
Gender
Equal
Prevalence
Rare
Gliomatosis cerebri is characterized by diffuse infiltration of neoplastic glial cells throughout the brain parenchyma. Tumor cells spread along white matter tracts, cortex, basal ganglia, and even brainstem and cerebellum while relatively preserving existing neuronal and axonal architecture — this 'preserved architecture' feature explains the minimal mass effect. Tumor cells infiltrate along existing perivascular spaces and white matter tracts (secondary structure pattern), expanding the brain parenchyma's organic structure without disrupting it. The extensive T2/FLAIR hyperintensity reflects increased water content and myelin damage around infiltrating tumor cells — neoplastic cells disrupting axonal myelin sheaths cause extracellular water increase and T2 prolongation. Absence or minimal enhancement indicates that the blood-brain barrier is largely preserved — tumor cells advance in perivascular spaces rather than invading vessel walls. As disease progresses, focal mass formation and enhancement may develop, indicating anaplastic transformation or high-grade glioma component. Mild diffusion restriction is explained by low-to-moderate cellularity of tumor cells spread over a wide area — different from the focal high cellularity of high-grade gliomas.
Extensive FLAIR hyperintensity encompassing at least three cerebral lobes with disproportionately minimal mass effect and absent enhancement relative to lesion extent — the most characteristic and diagnostic finding of gliomatosis cerebri. This combination reflects the tumor infiltrating while preserving existing brain architecture without disrupting the blood-brain barrier.
Diffuse hyperintensity on FLAIR encompassing at least three cerebral lobes — the most characteristic and diagnostically important finding of gliomatosis cerebri. Hyperintensity is predominant in white matter but may extend to cortex, basal ganglia, and thalamus. Corpus callosum involvement is common with bilateral spread. Brain architecture is relatively preserved — mass effect is minimal relative to lesion extent.
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Diffuse hyperintensity encompassing at least three cerebral lobes is observed on FLAIR, with relatively preserved brain architecture and minimal mass effect.
Diffuse white matter hyperintensity on T2-weighted images. Signal change spreads along white matter tracts and may extend to cortex and basal ganglia. Lesion extent may be slightly less conspicuous than FLAIR (confusion with CSF signal in periventricular area). Corpus callosum involvement indicates bilateral hemispheric spread.
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Diffuse white matter hyperintensity is observed on T2-weighted images, with findings encompassing multiple cerebral lobes.
Enhancement is typically absent or very minimal on post-gadolinium T1-weighted images. This finding is diagnostically important due to the disproportion between lesion extent and enhancement. Development of focal enhancement areas suggests anaplastic transformation or high-grade glioma component and is a poor prognostic sign.
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No significant enhancement is observed after gadolinium despite extensive T2/FLAIR signal abnormality, consistent with diffuse infiltrative glial neoplasm.
Mild to moderate diffusion abnormality may be seen in infiltrated areas on DWI; ADC values are lower than normal white matter but higher than high-grade gliomas. Prominent focal diffusion restriction is not expected. Development of focal marked restriction areas suggests high-grade transformation.
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Mild diffusion abnormality is observed in infiltrated areas on DWI without focal marked diffusion restriction.
MR Spectroscopy shows elevated choline (Cho) and reduced NAA in infiltrated areas — reflecting neoplastic cell proliferation and neuronal damage. Cho/NAA and Cho/Cr ratios are elevated. Myoinositol elevation is consistent with glial origin. Mild metabolite abnormality may be detected even in normal-appearing brain areas — indicating tumor spread beyond imaging-visible extent.
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Elevated choline and reduced NAA are observed in infiltrated areas on MR Spectroscopy, consistent with neoplastic infiltration; mild metabolite abnormality is also detected in normal-appearing areas.
Diffuse hypointensity in infiltrated white matter on T1-weighted images. Cortical thickening and blurring of gray-white matter junction may be seen in areas of cortical involvement. Focal mass formation is typically absent. Thickening and T1 hypointensity of corpus callosum indicates bilateral spread.
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Diffuse white matter hypointensity and blurring of gray-white matter junction are observed on T1-weighted images.
Criteria
Diffuse infiltration without focal tumor mass. No enhancement. Involvement of at least 3 lobes. Classic presentation.
Distinct Features
Completely diffuse pattern, minimal mass effect, no enhancement. Extensive FLAIR hyperintensity with preserved brain architecture. Mild restriction on DWI. Prognosis may be better than Type II.
Criteria
Focal mass formation on background of diffuse infiltration. Enhancement may be seen in focal area. High-grade glioma component present.
Distinct Features
Diffuse infiltration + focal mass. Enhancement, increased rCBV and marked diffusion restriction in focal area. High Cho/Cr ratio in focal area on MRS. Prognosis worse than Type I. Biopsy should target focal area.
Criteria
Brainstem and/or cerebellar involvement in addition to supratentorial diffuse infiltration. Associated with worse prognosis.
Distinct Features
Brainstem FLAIR hyperintensity and swelling, peduncular involvement, cerebellar white matter infiltration. Cranial nerve palsies (brainstem involvement). Hydrocephalus may develop. Treatment options more limited.
Distinguishing Feature
Low-grade astrocytoma typically presents as focal mass limited to one-two lobes, while gliomatosis cerebri diffusely involves at least three lobes. Mass effect in low-grade astrocytoma is proportional to lesion size.
Distinguishing Feature
Primary CNS lymphoma typically shows homogeneous intense enhancement (absent/minimal in gliomatosis), marked DWI restriction (mild in gliomatosis), presents as focal periventricular mass. Different from diffuse infiltrative pattern of gliomatosis cerebri.
Distinguishing Feature
Glioblastoma shows irregular ring enhancement, central necrosis, and prominent mass effect. Gliomatosis cerebri has absent/minimal enhancement and disproportionately minimal mass effect. However, Type II gliomatosis may contain focal glioblastoma component.
Distinguishing Feature
Acute infarct shows vascular territorial distribution (gliomatosis follows white matter tracts), marked DWI restriction (mild in gliomatosis), acute onset (subacute/chronic in gliomatosis). Infarct borders follow arterial supply territory.
Urgency
urgentManagement
medicalBiopsy
NeededFollow-up
Biyopsi sonrası moleküler profillemeye göre tedavi planı. 3 aylık aralıklarla MR takip. Klinik ve radyolojik progresyon değerlendirmesi.Gliomatosis cerebri is a condition with poor prognosis. Stereotactic brain biopsy is required for diagnosis — molecular profiling (IDH mutation, 1p/19q co-deletion, MGMT methylation) is critically important for treatment planning and prognosis estimation. Surgical resection is not possible due to diffuse nature. Treatment options: radiation therapy (whole brain or extended field), temozolomide chemotherapy. IDH-mutant cases have better prognosis. Median survival is 14-22 months but varies with molecular profile. Steroids (dexamethasone) are used for perilesional edema and symptom control.
Diffuse gliomatosis pattern has a poor prognosis (median survival 14-24 months). Surgical resection is not possible due to diffuse nature. Treatment involves radiotherapy and temozolomide-based chemotherapy. Biopsy for histological and molecular diagnosis (IDH, 1p/19q) determines treatment strategy.