chordoid glioma of the third ventricle , a rare neuroepithelial tumor of the central nervous system , mostly originates from the anterior part of the third ventricle .
chordoid glioma is classified as grade ii tumor according to 2007 world health organization ( who ) classification of brain tumors ( 1 ) .
approximately 85 cases of chordoid glioma have been reported in english literatures since its first report in 1998 ( 2 ) .
although chordoid glioma is located within the ventricular system , intraventricular seeding or metachronous tumors along the ventricular wall has not been reported .
herein , we present the first case of chordoid glioma arising from the third ventricle with multifocal intraventricular seeding in the lateral and fourth ventricles .
we also described perfusion mr imaging features of this case different from a previous report .
a head ct scan revealed a large high attenuated mass with lobulated margins and small calcifications in the anterior 3rd ventricle ( fig .
additional small hyper - attenuated masses along the ependymal surface of both lateral ventricles were also found .
a large area of peritumoral edema was noted in the left frontal periventricular white matter .
a brain mri revealed a 3.1  4.2  4.5 cm well defined multi - lobulated tumor in the anterior third ventricle and suprasellar region displacing the right lateral ventricle superiorly ( fig .
the mass showed iso - signal intensity on both t1- and t2-weighted images relative to the brain cortex .
postcontrast t1-weighted imaging also demonstrated additional multiple enhancing masses along the ependymal surface of lateral ventricles , the fourth ventricle , and in the bilateral foramen of luschka .
perfusion mri showed markedly elevated cerebral blood volume ( cbv ) within the tumors on cbv map ( fig .
the ratio of maximum tumor cbv relative to white matter was calculated using the following equation : maximum rcbv = maximum cbv tumor / maximum cbv white matter .
the maximum cbv was obtained using a circular region of interest with a diameter of 10 mm from each main tumor and the adjacent right frontal white matter .
the patient first underwent a tumor removal surgery for the daughter mass in the left lateral ventricle through a left frontal transcortical approach . at surgery , a hard multi - lobulated and encapsulated mass was found to be attached to the ependymal wall .
two months following the first surgery , a second operation was performed to remove the main tumor in the third ventricle .
the patient underwent tumor removal surgery via a bifrontal craniotomy and a transcallosal interhemispheric approach . at surgery , a hard whitish mass filling the anterior part of the third ventricle was found to be firmly attached to the hypothalamus .
on histology , these tumors consisted of clusters and cords of oval - to - polygonal epithelioid cells with eosinophilic cytoplasm in a mucinous stroma ( fig .
immunohistochemical analysis revealed that these tumor cells were diffusely positive for glial - fibrillary acid protein ( gfap ) , cd 34 , and vimentin .
in addition , they were focally positive for epithelial membrane antigen ( ema ) and s-100 protein ( fig . 1e , f ) with a ki-67 labeling index of less than 0.5% .
follow - up , the patient was doing well without any evidence of tumor recurrence in the third or lateral ventricles on follow - up mri .
follow - up mri also showed no changes in the size of small enhancing tumors in the fourth ventricle or foramen of luschka .
chordoid glioma is a rare low grade neuroepithelial tumor with both glial and chordoid features .
the tumor tends to occur in adult women ( a female to male ratio of 2 to 1 ) at mean age of 45 years ( range , 5 - 72 years ) ( 3 ) .
clinical symptoms including headache , nausea , vomiting , visual disturbances , confusion , lethargy , urinary incontinence , ataxia , hypothyroidism , diabetes insipidus , weight loss or weight gain , and behavioral disturbances due to intracranial hypertension , hydrocephalus , compression of the hypophysis , optic chiasm , and hypothalamus by the tumor ( 123 ) .
chordoid glioma is typically arising in the region of the anterior third ventricle / hypothalamus .
there have been a few reports regarding the unusual locations of chordoid glioma such as juxtaventricular white matter and thalamus ( 4 ) .
in contrast to previous reports , our case of chordoid glioma had a large main tumor in the third ventricle with multiple smaller masses in the lateral and fourth ventricles , suggesting intraventricular dissemination of the third ventricular tumor rather than concomitant tumor occurrence . given the location of the tumor , there is a possibility of intraventricular seeding of choroid glioma which has not been previously reported .
therefore , the true biological behavior of this tumor remains to be established ( 4 ) .
our case supports the idea that chordoid glioma might be derived from ependymal cells or tanycytes .
several studies have shown that tumor cells of chordoid glioma have features of ependymal differentiation on electron microscopy such as basal lamina , microvilli , and intermediate filaments ( 5 ) .
tanycytes are believed to be the primitive progenitor cells in the phylogenetic development of ependymal cells and glial cells .
they are primarily present in the circumventricular organs with predominance in the anterior portion of the third ventricle ( 6 ) .
brain tumors arising from the ependymal lining of the ventricles are likely to have cerebrospinal fluid ( csf ) seeding .
for example , csf seeding has been seen in about 8% to 33% of patients with ependymoma at presentation ( 7 ) .
although intraventricular seeding of diffuse who grade ii glioma is rare , it can occur during follow - up period after incomplete resections of primary tumor ( 8) . on imaging studies , chordoid gliomas are solid , ovoid in shape , well circumscribed , and located in the anterior third ventricle and/or suprasellar region . at ct , most tumors are hyperdense on unenhanced scan and enhanced homogenously after injection of contrast agent . at mri , chordoid gliomas have isosignal intensity on t1-weighted images and slightly hypersignal intensity on t2-weighted images .
there has been only one case report describing the perfusion mr imaging features of chordoid glioma .
grand et al . ( 9 ) have reported that the cbv of the tumor is not elevated compared to that of white matter .
the relative maximum cbv ratio was 6.95 in our case , suggesting that this tumor entity might be composed of heterogeneous subgroups .
however , t1-weighted leakage and t2- and/or t2 * -weighted imaging residual effects were not corrected in our case .
on histopathology , chordoid gliomas had characteristic appearance consisting of cords and clusters of epithelioid cells with eosinophilic cytoplasm and relatively uniform round to oval nuclei embedded in mucinous stroma ( 123 ) .
immunohistochemically , chordoid gliomas were strongly and diffusely positive for gfap , vimentin , cd 34 , and focally positive for ema and cytokeratin .
therefore , cd 34 can be used to differentiate chordoid glioma from chordoid meningioma , pilocytic astrocytoma , and ependymoma ( 3 ) .
our case was also diffusely positive for gfap , cd 34 , vimentin , and focally positive for ema and s-100 protein .
however , gross total resection is often difficult given its location in the deep structure of brain and its proximity to critical neurovascular structures .
therefore , a more conservative treatment approach other than surgical resection is warranted ( 10 ) . in our case
in addition , there was no change in remained tumor in the fourth ventricle on follow - up mri after 45 months of gross total resection , confirming the low grade nature of this tumor . using chemotherapy for chordoid glioma has not been reported . in conclusion
, we described the first case of chordoid glioma in the third ventricular with intraventricular dissemination in the lateral and fourth ventricles .
although chordoid glioma is a low grade tumor , the tumor can have elevated cbv on perfusion mr imaging .
 chordoid glioma is a rare low grade tumor typically located in the third ventricle . 
 although a chordoid glioma can arise from ventricle with tumor cells having features of ependymal differentiation , intraventricular dissemination has not been reported . here 
 we report a case of a patient with third ventricular chordoid glioma and intraventricular dissemination in the lateral and fourth ventricles . 
 we described the perfusion mr imaging features of our case different from a previous report . 
INTRODUCTION
CASE REPORT
DISCUSSION