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Chordoid Glioma of the Third Ventricle

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Definition

Well circumscribed, glial tumor of the third ventricle with a chordoma-like histologic features.

Clinical Features

Rare
Almost exclusively adults
Women > men1–6
Limited to third ventricular/suprasellar compartment
Presentation:
- obstructive hydrocephalus
- array of clinical manifestations including:
  - headache
  - ataxia
  - visual and endocrine disturbances
  - marked fluctuations of weight
  - psychotic/organic brain syndromes
Grow slowly
Do not:
- invade surrounding tissues
- metastasize via the CSF

Histopathology

Noninfiltrative growth pattern
Epithelioid oval to polygonal cells:
- within basophilic myxoid matrix prone to coarse vacuolation (Fig. 1
  Fig. 1: Chordoid glioma of the third ventricle. Nests and anastomosing cords of epithelioid tumor cells arrayed against a variably myxoid stromal background typify this lesion. Note the presence of plasma cells at lower right. These are often present in more conspicuous numbers.
  ), which may be:
  - PAS/DPAS-positive
  - faintly mucicarminophilic
Interstitial and perivascular infiltration by:
- lymphocytes
- Russell body-bearing plasma cells
Mitoses not found or rare:
- MIB-1 labeling indices generally 0–1.5%
No:
- conspicuous pleomorphism
- microvascular proliferation
- necrosis
Typically reactive gliosis of adjacent brain tissue with Rosenthal fiber formation
A unique pediatric example manifesting chondroid metaplasia recorded2
Ultrastructurally:
- appear to differentiate along ependymal lines:
  - in one case:
    - formation of desmosome-like cytoplasmic attachments
    - microvilli partially investing basal lamina4
    - aberrant juxtanuclear cilia1,3,5
no pathognomonic ependymal specializations such as microlumens delimited by intercellular junctional complexes of zonula adherens type
one example containing papillary perivascular pseudorosettes and alveolus-like structures 5
one report of ultrastructural properties shared with the specially modified ependymal cells of the subcommissural organ:
- an ostensibly secretory body in dorsocaudal aspect of third ventricle
- develops during embryonic life
- postnatal involution3
- common features included zonation of cell bodies into:
  - perinuclear region containing prominent profiles of rough endoplasmic reticulum and Golgi apparatus
  - intermediate region occupied principally by mitochondria, smooth endoplasmic reticulum and secretory-type granules
  - apical zone displaying rich complement of intermediate filaments and crowning microvilli

Special Stains and Immunohistochemistry

Characteristic immunoprofile:1–3
- consistently diffuse cytoplasmic labeling for:
  - GFAP (Fig. 2
    Fig. 2: Chordoid glioma of the third ventricle. Nests and anastomosing cords of epithelioid tumor cells arrayed against a variably myxoid stromal background typify this lesion, which is distinguished from other chordoid neoplasms by its diffuse cytoplasmic immunolabeling for GFAP.
    )
  - vimentin
- express CD34:
  - with cell membrane accentuation
- may be focally S-100 protein-positive
- EMA-negative or only focally EMA-immunoreactive
- limited labeling for variety of cytokeratins2,6
- AE1/3 ‘cocktail’ may yield pattern overlapping with GFAP preparations
- cytoplasmic immunolabeling for:
  - epidermal growth factor receptor
  - merlin/schwannomin
- no reactivity for:
  - p53 6

Other Investigations

Neuroradiology:
- large homogeneously contrast-enhancing mass
- solid
- sharply circumscribed

Differential Diagnosis

Select up to 2 differential diagnoses to compare with Chordoid Glioma of the Third Ventricle

Metastatic Carcinoma, Intradural Chordoma, Chordoid Meningioma

Differentiated by absence of:
- true gland formation
- physaliphorous cells
- cellular whorls
- intranuclear pseudoinclusions
- psammoma bodies

Management

Resection:
- attachment to hypothalamic/suprasellar structures complicates removal
- pulmonary thromboembolism accounts for disproportionate share of deaths in immediate postoperative period1,6
Incomplete resection:
- can regrow and prove fatal 1
Role of adjuvant therapy undefined

References

1 Brat DJ, Scheithauer BW, Staugaitis SM, Cortez SC, Brecher K, Burger PC. Third ventricular chordoid glioma. A distinct clinicopathologic entity. J Neuropathol Exp Neurol. 1998;57:283–290.

2 Castellano-Sanchez AA, Schemankewitz E, Mazewski C, Brat DJ. Pediatric chordoid glioma with chondroid metaplasia. Pediatr Dev Pathol. 2001;4:564–567.

3 Cenacchi G, Roncaroli F, Cerasoli S, Ficarra G, Merli GA, Giangaspero F. Chordoid glioma of the third ventricle. An ultrastructural study of three cases with a histogenetic hypothesis. Am J Surg Pathol. 2001;25:401–405.

4 Pasquier B, Peoc'h M, Morrison AL, Gay E, Pasquier D, Grand S, et al. Chordoid glioma of the third ventricle. A report of two new cases, with further evidence supporting an ependymal differentiation, and review of the literature. Am J Surg Pathol. 2002;26:1330–1342.

5 Raizer JJ, Shetty T, Gutin P, Obbens E, Holodny A, Antonescu CR, et al. Chordoid glioma. Report of a case with unusual histologic features, ultrastructural study and review of the literature. J Neurooncol. 2003;63:39–47.

6 Reifenberger G, Weber T, Weber RG, Wolter M, Brandis A, Kuchelmeister K, et al. Chordoid glioma of the third ventricle. Immunohistochemical and molecular genetic characterization of a novel tumor entity. Brain Pathol. 1999;9:617–626.

Last updated: 12 Feb 2006