Rosette-forming glioneuronal tumours

Rosette-forming glioneural tumours (RGNTs) are midline tumours first described in 1998 by Komori et al., that involve the fourth ventricle or aqueduct of Sylvius

Although relatively well circumscribed on MRI and clinically extremely indolent, they often invade surrounding tissues, involving the cerebellum, pons and even the pineal region. There are often cystic components and they tend to have heterogeneous contrast enhancement. They are WHO grade I lesions.

It is a tumour of middle age adults with a mean age of 30 years. Symptoms mainly depend on the location of the tumour; commonly presenting with ataxia and headache. 

Histological features superficially resemble DNETs and contain both neurocytic and astrocytic components. 

Location

RGNTs are originally described in the region of the 4th ventricle (59%) often with variable local parenchymal extension 3. Recent literature review has demonstrated RGNTs outside the characteristic location. RGNTs has been described in locations such as the cerebellum hemisphere, cerebellopontine angle, pineal gland, tectum, thalamus, third ventricle, optic chiasm and spinal cord 3.

MRI
  • variable solid-cystic components 3:
    • RGNTs appear as solid lesions in 40%
    • mixed solid and cystic changes are seen in 35% cases
    • cystic only features in 25%  
  • the majority of RGNT (70%) show variable gadolinium enhancement 3:
    • focal enhancement pattern was most commonly observed (50%)
    • heterogeneous pattern (19%)
    • minimal enhancement (13%)
    • ring and nodular enhancement pattern (9%). 
  • calcification (25%) 3 
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Article Information

rID: 1993
Section: Pathology
Tag: cases
Synonyms or Alternate Spellings:
  • Rosette-forming glioneuronal tumour of the fourth ventricle
  • RGNT of fourth ventricle
  • Rosette-forming glioneuronal tumor of the fourth ventricle
  • Rosette-forming glioneuronal tumours of the fourth ventricle
  • Rosette-forming glioneuronal tumors of the fourth ventricle
  • RGNT
  • Rosette-forming glioneuronal tumour
  • Rosette-forming glioneuronal tumors
  • Rosette-forming glioneuronal tumor

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