Gliomatosis cerebri is a rare growth pattern of diffuse gliomas that involves at least three lobes by definition. There often is an important discordance between clinical and radiological findings, as it may be clinically silent while it appears as a very extensive process radiologically.
Importantly, whereas gliomatosis was previously considered a distinct entity since the 2016 update to the WHO classification of CNS tumours it is now merely thought of as a growth pattern 8.
- peak incidence is 20-40 years of age
- M:F of 1.5:1 in one sequential series of 54 patients 7
The tumour may be primary (de novo) or secondary, with the latter as a result from the spreading of a more focal glioma 5. Gliomatosis cerebri growth pattern is seen in all diffuse gliomas and can contain areas of WHO grade II or III tumours and rarely grade IV 6,7. It is most commonly encountered in anaplastic astrocytomas 8.
Gliomatosis cerebri can be divided into two types 7:
- type 1: no discrete mass
- usually IDH wild-type 8
- type 2: discrete mass with further diffuse CNS involvement
- IDH1 mutation more common in this subtype 7
CT can be normal as lesions are often isodense to normal brain parenchyma. There is a relative lack of mass effect and distortion compared to the extensiveness of involvement. There may be an ill-defined asymmetry or subtle hypoattenuation of the involved brain parenchyma.
Mass effect and enhancement are often minimal despite large portions of the brain being involved. There is a loss of grey-white matter differentiation and diffuse gyral thickening.
Diffuse T1 and T2 prolongation throughout both white and grey matter:
- T1: iso to hypointense to grey matter 1
- T2: hyperintense to grey matter 1
- T1C+ (Gd): typically no or minimal enhancement
- DWI: usually no restriction
- elevated Cho:Cr and Cho:NAA ratios 2
- marked elevation of myoinositol (mI)
- low/normal rCBV: correlates with no vascular hyperplasia
- FDG-PET shows marked hypometabolism
Treatment and prognosis
The condition carries a poor prognosis with an average survival of ~50% at 1 year and 25% at 3 years. Transformation into glioblastoma may occur a few years later.
Surgery is not a viable option due to the diffuse nature of this tumour but can be used to treat complications such as hydrocephalus or mass effect.
Radiation therapy has been shown to increase survival 7, however, the large field usually required in these lesions increases the risk of severe toxicity 5. Chemotherapy is a treatment option, although there is a lack of evidence in its use (both positive and negative) 7.
General imaging differential considerations include 6:
- 1. Shin YM, Chang KH, Han MH et-al. Gliomatosis cerebri: comparison of MR and CT features. AJR Am J Roentgenol. 1993;161 (4): 859-62. AJR Am J Roentgenol (abstract) - Pubmed citation
- 2. Bendszus M, Warmuth-metz M, Klein R et-al. MR spectroscopy in gliomatosis cerebri. AJNR Am J Neuroradiol. 2000;21 (2): 375-80. AJNR Am J Neuroradiol (full text) - Pubmed citation
- 3. Del carpio-o'donovan R, Korah I, Salazar A et-al. Gliomatosis cerebri. Radiology. 1996;198 (3): 831-5. Radiology (abstract) - Pubmed citation
- 4. Yu A, Li K, Li H. Value of diagnosis and differential diagnosis of MRI and MR spectroscopy in gliomatosis cerebri. Eur J Radiol. 2006;59 (2): 216-21. doi:10.1016/j.ejrad.2006.03.001 - Pubmed citation
- 5. Sanson M, Napolitano M, Cartalat-Carel S et-al. Gliomatosis cerebri. Rev. Neurol. (Paris). 2005;161 (2): 173-81. Pubmed citation
- 6. Castillo M. Neuroradiology Companion: Methods, Guidelines, and Imaging Fundamentals. LWW. ISBN:1451111754. Read it at Google Books - Find it at Amazon
- 7. Chen S, Tanaka S, Giannini C et-al. Gliomatosis cerebri: clinical characteristics, management, and outcomes. J. Neurooncol. 2013;112 (2): 267-75. doi:10.1007/s11060-013-1058-x - Free text at pubmed - Pubmed citation
- 8. David N. Louis, Hiroko Ohgaki, Otmar D. Wiestler and Wbster K. Cavenee. International Agency for Research on Cancer, WHO Classification of Tumours of the Central Nervous System. 2016 Revision ISBN: 9789283244929
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