"This morphology, combined with common chromosome arm 1p deletions, sometimes with co-deletion of 19q, accounts for its prior name including the term "oligodendroglial-like" (see 1p19q codeletion). In contrast to oligodendrogliomas, diffuse leptomeningeal glioneuronal tumours do not have IDH mutations 2,5."
"KIAA1549-BRAF fusion (common)"
"GFAP (patchy immunoreactivity) seen in less than 50% of cases"
"Negative for neurofilament and EMA, and no IDH mutations 1,2,5."
"S-100 (diffuse immunoreactivity)"
Expected headings
"Grading"
"Clinical presentation is dominated by hydrocephalus due to the pronounced accumulation of tumour within the subarachnoid space. Occasionally, patients may present with focal neurological symptoms, including cranial nerve impairment, ataxia and spinal cord compression, or with seizures 3,5."
"Most of these tumours have a low-grade histological appearance, with commensurately low mitotic index ("
"A further finding, which is believed to be fairly specific for this entity, is the presence of numerous small subpial cysts (high T2, low T1, FLAIR attenuating) located over the surface of the inferior parts of the cerebral hemispheres (temporal lobes, inferior frontal lobes), posterior fossa (cerebellum and brainstem) and spinal cord 5. It is thought that perhaps these represent dilatation of the perivascular spaces (Virchow-Robin spaces) 1."
"A further finding, which is believed to be fairly specific for this entity, is the presence of numerous small subpial cysts (high T2, low T1, FLAIR attenuating) located over the surface of the inferior parts of the cerebral hemispheres (temporal lobes, inferior frontal lobes), posterior fossa (cerebellum and brainstem) and spinal cord 5. It is thought that perhaps these represent dilatation of the perivascular spaces (Virchow-Robin spaces) 1."
"Although diffuse leptomeningeal glioneuronal tumours demonstrate fairly indolent growth, morbidity is quite prominent due to profound hydrocephalus 2. To complicate matters further, the entity has only been described and the literature is confusing; it is unclear if all reported cases are, in fact, of the same entity. Survival varies widely, reported in some instances to be quite low, with an average survival of only 22 months 3, whereas other series have long follow-up 4,5."