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Diffuse midline glioma, H3 K27M–mutant (view source)
Revision as of 17:31, 13 April 2017
, 17:31, 13 April 2017no edit summary
==Synonyms / Terminology==
==Synonyms / Terminology==
Histone H3.3 is a protein that in humans is encoded by the H3F3A gene. Mutations of H3F3A are linked to certain cancers. p.Lys27Met were discovered in Diffuse Intrinsic Pontine Glioma (DIPG), where they are present 65-75% of tumors and confer a worse prognosis. p.Lys27Met alterations in HIST1H3B and HIST1H3C, which code for histone H3.1 have been reported in ~10% of DIPG (7,8).
==Epidemiology / Prevalence==
==Epidemiology / Prevalence==
Adults (2): Predominately younger adults (<40 yrs); but can occur at any age
2-7.5% of adult IDH wild-type astrocytomas
37.5-66% of adult midline gliomas
Pediatric & young adult3: Majority of diffuse intrinsic pontine gliomas (DIPG), thalamic glioblastomas (GBM)
Median age 5-11 years with pontine tumors arising at ~7 years and thalamic tumors at ~11 years
==Clinical Features==
==Clinical Features==
The clinical presentation – brainstem dysfunction, CSF obstruction, increase intracranial pressure, ataxia, cranial nerve injury, progressive sensorimotor deficits.
==Sites of Involvement==
==Sites of Involvement==
Midline locations: brainstem (midbrain, pons, floor 4th ventricle, medulla oblongata), spinal cord, thalamus; Other locations: hypothalamus, pineal region, cerebellum
==Morphologic Features==
==Morphologic Features==
Histopathology – astrocytic morphology – can range from diffuse low-grade glioma to high grade glioma.
H3 K27M-mutant gliomas can display a broad spectrum of histological features, including giant, epithelioid, and rhabdoid cells; primitive neuroectodermal tumor–like foci; ependymal-like areas; sarcomatous transformation, as well as features that may wrongly suggest circumscribed gliomas such as neuropil-like islands, pilomyxoid features, ganglionic differentiation, and pleomorphic xanthoastrocytoma-like areas.
==Immunophenotype==
==Immunophenotype==