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Rosette-Forming Glioneuronal Tumor (RGNT)

Last Updated: March 27, 2020

Open Table of Contents: Rosette-Forming Glioneuronal Tumor (RGNT)

Figure 1: This mildly complex, circumscribed T2-FLAIR hyperintense rosette-forming glioneuronal tumor fills and expands the fourth ventricle (left), contributing to hydrocephalus in this patient, but causes little edema. The tumor demonstrates a heterogeneous internal pattern of enhancement (right).

Basic Description

  • Uncommon, slow-growing, and benign tumor usually arising in the posterior fossa

Pathology

  • WHO grade I
  • Composed of pseudorosette-forming neurocytes and astrocytes
  • No malignant transformation

Clinical Features

  • Affects young adults (mean 30 years old)
  • Female gender predilection (2:1)
  • Commonly presents with signs/symptoms of increased intracranial pressure secondary to obstructive hydrocephalus
    • Headache, nausea, ataxia, vertigo
  • Treatment: surgical resection
  • Prognosis: recurrence uncommon following total resection; 5-year survival 90%

Imaging Features

  • General
    • Mixed solid-cystic tumor ± calcification, hemorrhage; may be solid
    • Minimal peritumoral edema
    • Majority arise in 4th ventricle or midline cerebellum
    • Pineal, CPA cistern, or hemispheric locations are uncommon
  • CT

    • Solid-cystic midline posterior fossa mass
  • MRI

    • T1WI: hypo- to isointense
    • T2WI: usually hyperintense with cystic or bubbly appearance; ± flow voids
    • FLAIR: heterogeneously hyperintense
    • T2*/GRE/SWI: black signal blooming in foci of calcification, hemorrhage
    • T1WI+C: variable enhancement

Imaging Recommendations

  • MRI with contrast

For more information, please see the corresponding chapter in Radiopaedia.

Contributor: Rachel Seltman, MD

DOI: https://doi.org/10.18791/nsatlas.v1.03.01.37

References

Hsu C, et al. Rosette-forming glioneuronal tumour: Imaging features, histopathological correlation and a comprehensive review of literature. Br J Neurosurg. 2012;26:668-673.

Schlamann A, et al. An individual patient data meta-analysis on characteristics and outcome of patients with papillary glioneuronal tumor, rosette glioneuronal tumor with neuropil-like islands and rosette forming glioneuronal tumor of the fourth ventricle. PLoS One. 2014;9:e101211.

Osborn AG, Salzman KL, Jhaveri MD. Diagnostic Imaging (3rd ed). Philadelphia, PA: Elsevier, 2016.

Smith AB, et al. From the radiologic pathology archives: intraventricular neoplasms: radiologic-pathologic correlation. Radiographics. 2013;33:21-43.

Zhang J, et al. A comprehensive analysis of 41 patients with rosette-forming glioneuronal tumors of the fourth ventricle. J Clin Neurosci. 2013;20:335-341.

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