CNS tumor
Neuronal and mixed neuronal - glial tumors
Rosette forming glioneuronal tumor (RGNT)

Author: Eman Abdelzaher, M.D., Ph.D. (see Authors page)

Revised: 1 September 2017, last major update July 2014

Copyright: (c) 2002-2017, PathologyOutlines.com, Inc.

PubMed Search: Rosette forming glioneuronal tumor [title]

Cite this page: Abdelzaher, E. Rosette forming glioneuronal tumor (RGNT). PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/cnstumorRGNT.html. Accessed October 20th, 2017.
Definition / general
Sites
Clinical features
  • Affects children and young adults (mean age 33 years, range 12 - 59 years)
  • Slight female predilection
  • Presents with headache, ataxia
Radiology description
  • Relatively circumscribed, solid or cystic
  • Contrast enhancement: at least focal
  • ± Calcifications, ± minimal edema
Radiology images

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Various images

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Posterior fossa mass

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Hyperintense tumor of midbrain

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Suprasellar mass with intratumoral hemorrhage

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Mass centered in pineal region

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Well defined lesion in pineal gland

Prognosis
  • Favorable clinical outcome
  • Favorable prognosis in terms of survival but location may complicate surgical removal with a significant risk of neurologic injury
Case reports
Treatment
  • Gross total surgical resection
Microscopic (histologic) description
  • Relatively well defined tumor parenchyma interface
  • Characterized by biphasic neurocytic and glial components
  • Neurocytic component consists of uniform neurocytes that form neurocytic rosettes or perivascular pseudorosettes
    • Neurocytic elements may lie unanchored in microcystic mucinous areas
    • Ganglion cells may be present
  • Glial component is usually identical to pilocytic astrocytoma with Rosenthal fibers and eosinophilic granular bodies (EGB)
    • May show oligodendroglia-like cells that form microcysts or aggregate in sheets
  • Mitoses, necrosis are absent and atypia is minimal
  • Also stromal alterations indicative of chronicity and degeneration, vascular sclerosis, dense collagenization, microcalcifications, hemosiderin deposits, focal infarction
  • Blood vessels are thin walled, ectatic or hyalinized, with glomeruloid microvascular proliferation
Microscopic (histologic) images

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Contributed by Dr. Eman Abdelzaher

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Numerous neurocytic rosettes

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Neurocytic rosettes

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Various images


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H&E, GFAP, synaptophysin

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GFAP

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Synaptophysin

Cytology description
  • Uniform nuclei, rosettes
Immunohistochemistry
  • Neuronal component: synaptophysin+, NSE+, MAP2+
  • Glial component: GFAP+, S100+
  • Oligodendroglia-like cells: synaptophysin-, GFAP-, variable S100
  • Low Ki67 proliferation index: < 3%
Electron microscopy description
  • Neuronal component: microtubules and occasional dense core granules and synapses
  • Glial component: dense bundles of glial filaments
Differential diagnosis