Chordoid meningiomas are uncommon histological variants of meningiomas, and due to their predilection for rapid growth and local recurrence are designated as grade 2 tumours under the current WHO classification of CNS tumours.
Chordoid tumours are encountered in a very wide age range (possibly somewhat younger than other meningiomas 3), in a wide range of locations within the intracranial cavity and have clinical presentations indistinguishable from other meningiomas 1,2. These are therefore discussed in the main meningioma article.
An association with Castleman disease was part of the original description but is only uncommonly encountered 3-5.
Chordoid meningiomas have characteristic histological appearances, which contribute to their distinctive diffusion characteristics on imaging (see below).
The epithelioid tumour cells demonstrate cytoplasmic vacuolization and are embedded in a mucoid matrix which has abundant hyaluronic acid and chondroitin sulfate 1,2.
The mitotic index of these tumours has been variably reported (0.4-11.4%) and it is likely that this is not the underlying cause of higher reported recurrence rate 3.
Chordoid tumours are usually vimentin EMA positive, and GFAP negative 5.
T1 and T2 signal characteristics are generally similar to other meningiomas, and no morphological features are particularly helpful in distinguishing chordoid meningiomas from other variants 1. Generally, they are probably more heterogeneous and perhaps more likely to involve adjacent bone, however, limited numbers in reported series make this difficult to assess 1,2.
- typically isointense to grey matter (same as typical grade 1 meningiomas)
- typically mildly hyperintense to grey matter (grade 1 tumours are typically isointense)
- peritumoral oedema is variable (absent to pronounced)
- most a vividly enhancing
- occasional areas of non-enhancement due to necrosis are identified 1
The most helpful MRI feature in distinguishing a chordoid meningiomas from other histological variants are their diffusion characteristics. They typically have facilitated diffusion with a mean ADC value of 1620 +/- 0.33 x 10-6 mm2/s according to one study 1. In contrast, WHO grade 1 meningiomas, non-chordoid grade 2 tumours and grade 3 tumours all have more pronounced diffusion restriction, similar or lower to brain parenchyma (~800 x 10-6 mm2/s).
Treatment and prognosis
Chordoid meningiomas are treated with surgical excision and if complete resection is accomplished then a cure is possible. In subtotal resection (Simpson grade 4) or in cases of recurrence, radiotherapy is also often used 5.
They are, however, considered WHO grade 2 tumours on account of a higher rate of local recurrence (up to 42%) 3.
History and etymology
Chordoid meningiomas were first described in 1980 (single case report in a 15-year old) 6 and subsequently named 1988 4.
In addition to all other histological variants of meningiomas (especially microcystic subtype), chordoid meningiomas need to be distinguished from other extra-axial tumours with an abundant extracellular matrix. Therefore the differential includes:
- typically demonstrate brighter T2 signal
- less facilitated diffusion 1
- typically arising in the midline from the clivus
- almost invariably associated with bony destruction
- typically arising from the central base of the skull, near the petroclival synchondrosis
- may have chondroid ossification (rings and arcs)
- myxoid soft-tissue tumours
- 1. Pond JB, Morgan TG, Hatanpaa KJ et-al. Chordoid Meningioma: Differentiating a Rare World Health Organization Grade II Tumor from Other Meningioma Histologic Subtypes Using MRI. AJNR Am J Neuroradiol. 2015;36 (7): 1253-8. doi:10.3174/ajnr.A4309 - Pubmed citation
- 2. Zhu HD, Chen H, Xie Q et-al. Chordoid meningioma: a retrospective study of 17 cases at a single institution. Chin. Med. J. 2013;126 (4): 789-91. Pubmed citation. Full text
- 3. Epari S, Sharma MC, Sarkar C et-al. Chordoid meningioma, an uncommon variant of meningioma: a clinicopathologic study of 12 cases. J. Neurooncol. 2006;78 (3): 263-9. doi:10.1007/s11060-005-9092-y - Pubmed citation
- 4. Kepes JJ, Chen WY, Connors MH et-al. "Chordoid" meningeal tumors in young individuals with peritumoral lymphoplasmacellular infiltrates causing systemic manifestations of the Castleman syndrome. A report of seven cases. Cancer. 1988;62 (2): 391-406. Pubmed citation
- 5. Baum J. Chordoid Meningioma: A Short Series of Five Cases at a Single Institution and Literature Review. Read relevant article. Accessed on 10/01/2016
- 6. Connors MH. Growth and maturation arrest, hypochromic anemia and hyperglobulinemia associated with a brain tumor. West. J. Med. 1981;133 (2): 160-3. Free text at pubmed - Pubmed citation
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