Low-grade glioma
Low-grade gliomas (LGGs) are a diverse group of WHO grade I – WHO grade II of glial origin with pilocytic astrocytoma (PA) being the most frequent LGG diagnosis. It is now generally accepted that PA and most other LGGs are a single pathway disease of the MAPK signal transduction pathway 1).
Epidemiology
Classification
Risk Factors
The most frequent cancer predisposition syndromes in the LGG cohorts are Neurofibromatosis type 1 (NF1), with mostly pilocytic astrocytoma constituting around 10–20 % of LGG cases, and Tuberous Sclerosis Complex (TSC) with the characteristic subependymal giant cell astrocytoma (SEGA), constituting 1–2 % of LGG cases, respectively 2) 3)
Clinical features
Preoperative seizures could reflect intrinsic glioma properties 4).
Most patients experience epileptic seizures as a presenting symptom 5) 6) 7) 8) and cause medically-intractable seizure.
see Incidental low grade glioma.
The results of a genomic analysis suggest that low FOXO4 expression is a significant risk factor for epileptic seizures in patients with LGGs and is associated with the seizure outcome. FOXO4 may be a potential therapeutic target for tumor-associated epilepsy 9).
In patients with low-grade glioma (LGG), language deficits are usually only found and investigated after surgery. Deficits may be present before surgery but to date, studies have yielded varying results regarding the extent of this problem and in what language domains deficits may occur.
Twenty-three patients were tested using a comprehensive test battery that consisted of standard aphasia tests and tests of lexical retrieval and high-level language functions. The patients were also asked whether they had noticed any change in their use of language or ability to communicate. The test scores were compared to a matched reference group and to clinical norms. The presumed LGG group performed significantly worse than the reference group on two tests of lexical retrieval. Since five patients after surgery were discovered to have a high-grade glioma, a separate analysis excluding them were performed. These analyses revealed comparable results; however one test of word fluency was no longer significant. Individually, the majority exhibited normal or nearly normal language ability and only a few reported subjective changes in language or ability to communicate. This study shows that patients who have been diagnosed with LGG generally show mild or no language deficits on either objective or subjective assessment 10).