Chordoid glioma of the third ventricle: an ultrastructural study of three cases with a histogenetic hypothesis

[Chordoid gliomas of the third ventricle]

BACKGROUND

Chordoid glioma is a rare slow-growing tumor of the central nervous system. Available world experience includes no more than 200 cases (lesion of the third ventricle in absolute majority of cases). Recognition and treatment of chordoid glioma are currently difficult problems due to small incidence of this disease.

OBJECTIVE

To describe clinical manifestations and surgical treatment of chordoid glioma of the third ventricle considering literature data and own experience.

MATERIAL AND METHODS

There were 12 patients (6 men and 6 women) with chordoid glioma between 2004 and 2023 (10 patients with lesion of the third ventricle, 1 - lateral ventricle, 1 - pineal region). Only patients with tumors of the third ventricle were analyzed.

RESULTS

Total and subtotal resection was performed in 1 and 3 cases, respectively. Five patients underwent partial resection, 1 patient underwent biopsy. The follow-up data were available in 7 out of 10 patients (mean 25 months). Radiotherapy was performed in 4 patients (continued tumor growth in 2 cases). One patient died.

CONCLUSION

Chordoid glioma is a benign tumor predominantly localized in the third ventricle. Preoperative MRI and CT in some cases make it possible to suspect chordoid glioma and differentiate this tumor from craniopharyngioma, meningioma and pituitary adenoma by such signs as isointense signal in T1WI, hyper- or isointense signal in T2WI, homogeneous contrast enhancement and edema of basal ganglia in T2 FLAIR images. The only effective treatment for chordoid glioma is surgery. Total resection is often impossible or extremely dangerous due to location of tumor, large size and invasion of the third ventricle. Postoperative mental disorders and diabetes insipidus, including severe hypernatremia, are common that requires mandatory monitoring of water and electrolyte balance.

Benign Glioma

Benign glioma broadly refers to a heterogeneous group of slow-growing glial tumors with low proliferative rates and a more indolent clinical course. These tumors may also be described as "low-grade" glioma (LGG) and are classified as WHO grade I or II lesions according to the Classification of Tumors of the Central Nervous System (CNS) (Louis et al. in Acta Neuropathol 114:97-109, 2007). Advances in molecular genetics have improved understanding of glioma tumorigenesis, leading to the identification of common mutation profiles with significant treatment and prognostic implications. The most recent WHO 2016 classification system has introduced several notable changes in the way that gliomas are diagnosed, with a new emphasis on molecular features as key factors in differentiation (Wesseling and Capper in Neuropathol Appl Neurobiol 44:139-150, 2018). Benign gliomas have a predilection for younger patients and are among the most frequently diagnosed tumors in children and young adults (Ostrom et al. in Neuro Oncol 22:iv1-iv96, 2020). These tumors can be separated into two clinically distinct subgroups. The first group is of focal, well-circumscribed lesions that notably are not associated with an increased risk of malignant transformation. Primarily diagnosed in pediatric patients, these WHO grade I tumors may be cured with surgical resection alone (Sturm et al. in J Clin Oncol 35:2370-2377, 2017). Recurrence rates are low, and the prognosis for these patients is excellent (Ostrom et al. in Neuro Oncol 22:iv1-iv96, 2020). Diffuse gliomas are WHO grade II lesions with a more infiltrative pattern of growth and high propensity for recurrence. These tumors are primarily diagnosed in young adult patients, and classically present with seizures (Pallud et al. Brain 137:449-462, 2014). The term "benign" is a misnomer in many cases, as the natural history of these tumors is with malignant transformation and recurrence as grade III or grade IV tumors (Jooma et al. in J Neurosurg 14:356-363, 2019). For all LGG, surgery with maximal safe resection is the treatment of choice for both primary and recurrent tumors. The goal of surgery should be for gross total resection (GTR), as complete tumor removal is associated with higher rates of tumor control and seizure freedom. Chemotherapy and radiation therapy (RT), while not typically a component of first-line treatment in most cases, may be employed as adjunctive therapy in high-risk or recurrent tumors and in some select cases. The prognosis of benign gliomas varies widely; non-infiltrative tumor subtypes generally have an excellent prognosis, while diffusely infiltrative tumors, although slow-growing, are eventually fatal (Sturm et al. in J Clin Oncol 35:2370-2377, 2017). This chapter reviews the shared and unique individual features of the benign glioma including diffuse glioma, pilocytic astrocytoma and pilomyxoid astrocytoma (PMA), subependymal giant cell astrocytoma (SEGA), pleomorphic xanthoastrocytoma (PXA), subependymoma (SE), angiocentric glioma (AG), and chordoid glioma (CG). Also discussed is ganglioglioma (GG), a mixed neuronal-glial tumor that represents a notable diagnosis in the differential for other LGG (Wesseling and Capper 2018). Ependymomas of the brain and spinal cord, including major histologic subtypes, are discussed in other chapters.

Occurrence of Chordoid Glioma With Sodium Ion Metabolism Disorder 5 Years After Meningioma Surgery and Whole-Exome Sequencing: A Case Report and Literature Review

Chordoid glioma (CG), a rare slow-growing brain tumor, mainly occurs in the region of the third ventricle. Although its degree of malignancy is relatively low, its clinical prognosis is poor due to obscure clinical manifestations and the particular growing position. Currently, gross total resection is the best available method for treatment of CG. However, the tumor is located in the deep structure of the brain and close to neurovascular structure so it is difficult to remove completely. This study reported a case of CG of the third ventricle 5 years after surgery of right frontal parietal fibrous meningioma, accompanied with peri and post-operative sodium ion metabolism disorder. Whole-exome sequencing (WES) revealed 25 gene mutations shared by meningioma and CG. In addition, the PRKCA ^D463H CG marker gene mutation also existed in this patient. We reviewed the latest literature on this rare brain tumor, summarized its clinical manifestations, imaging and pathological characteristics, and discussed the mechanism related to its occurrence and the reasons for sodium ion disorder.

Intracranial chordoid glioma: A clinical, radiological and pathological study of 14 cases

BACKGROUND

Chordoid gliomas (CGs) are rare neuroepithelial tumors, which commonly arise from the anterior part of the third ventricle. Most studies on CGs included only one or two cases. To better understand the disease, we report 14 patients with pathologically confirmed CGs.

METHOD

The clinical characteristics, including radiological and histological examination, operative records, and prognoses were analyzed and reviewed.

RESULT

The case series included six male and eight female patients with an average age of 44.4 years. The most common preoperative symptom was headache (64.3%) and visual deterioration (57.1%). Radiological results showed that the third ventricle (12/14) was the most common site of the brain involved, and the lesions presented with solid (n = 9, 64.3%) or cystic-solid (n = 5, 35.7%) appearance. All patients were misdiagnosed as non-CG tumors. The operation approach was mainly determined by tumor location, thus trans-callosal approach (9/14) and trans-laminar terminalis approach were commonly used. Gross total resection (GTR) was achieved in all cases and none of them received any adjuvant therapy postoperatively. The most frequent postoperative complications were diabetes insipidus, electrolyte disturbance, hypopituitarism, cognitive dysfunction, and obstructive hydrocephalus. During an average follow-up period of 40.1 months, 2 cases (14.3%) were died of refractory hypopituitarism and pulmonary embolism, respectively. The preoperative symptoms and postoperative complications were all significantly improved in other 12 patients, and MRI showed no tumor recurrence.

CONCLUSION

According to our experience, we recommend GTR as the primary goal, which is associated with improved rates of tumor control and without increasing rates of postoperative complications.

Chordoid Glioma of the Third Ventricle: A Case Report and a Treatment Strategy to This Rare Tumor

Chordoid glioma (CG) of the third ventricle is a rare type of brain tumor. Here, we present a case, review of the literature and proposed a treatment strategy for this rare tumor. Here, A 33-years-old woman presented with the menstrual disorder and progressive obesity. Magnetic resonance imaging showed a large irregularly circular tumor in the third ventricle. The tumor was subtotally resected by microsurgery via the right modified port approach. Immunohistochemical staining was positive for glial fibrillary acidic protein (GFAP), Vimentin and transcription termination factor-1 (TTF-1), and the Ki-67 proliferation index was low (5%), which indicating CG. Residual tumor decreased after treated by Gamma Knife radiosurgery (GKRS) with a dose of 15 Gy. During 30 months of follow-up, the tumor did not recur, and the patient suffered no complications. The diagnosis of CG requires a combination of clinical presentation, neuroimaging, and pathology. The ideal therapy is gross total resection (GTR) of the tumor. However, GTR is usually difficult and carries a high risk of postoperative complications because of the tumor location. This case indicates that planed subtotal resection followed by GKRS with a proper marginal dose could be a good treatment strategy for CG.

Chordoid glioma: an entity occurring not exclusively in the third ventricle

Chordoid gliomas are extremely rare entities, which are generally considered occurring exclusively in the third ventricle. Despite the low-grade histological grade, aggressive behaviors have been reported in literatures. Due to the low morbidity, the origins, clinical, and radiological features, management and prognosis are still yet to be well elucidated. We retrospectively reviewed the clinical profiles from a series of 6 patients with chordoid gliomas. All patients underwent surgical treatment, and the diagnoses were based on histopathological examinations. Magnetic resonance imaging (MRI) was performed perioperatively. Follow-up outcomes were presented. This case series consisted of three male and three female patients (age range 27-67 years; mean age 43.3 years). MRI results showed tumors in the third ventricle (4/6), temporal-parietal-occipital lobe involving the lateral ventricle (1/6), and cerebellar hemisphere (1/6). Three tumors were solid, and the others were cystic-solid. Hydrocephalus was present in one patient. The T1-weighted imaging showed hypo- to isointensity, and T2-weighted imaging showed iso- to hyperintensity; enhancement was homogeneous (4/6) or heterogeneous (2/6). Diffusion-weighted imaging showed no evidence of restricted diffusion. Magnetic resonance spectrum showed an elevated choline value and reduced N-acetylaspartate value. Gross total resection was achieved in all patients, and during an average follow-up period of 35.8 months, no recurrence was noted. Chordoid gliomas can occur outside the third ventricle with a great diagnostic challenge. The MRI characteristics suggest a low-grade tumor, and the accurate diagnosis depends on pathological criteria. Complete surgical resection is associated with a favorable outcome.

Expanded Endoscopic Transnasal Approach to the Chordoid Glioma of the Third Ventricle : The First Case Ever Reported

Chordoid glioma of the third ventricle is a rare and challenging tumor to surgery because of its unique anatomical location and its close juxtaposition to the neurovascular structures and hypothalamus. The authors report a case of chordoid glioma of the third ventricle in a 43-year-old woman, who presented with headache and somnolence. The tumor was approached by endoscopic transnasal technique with a favorable result. Histopathologic examination disclosed a neoplastic tissue composed of eosinophilic epithelioid cells, mucinous, periodic acid Schiff-diastase positive, extracellular matrix, and scattered lymphoplasmacytic infiltrates. The best treatment option remains controversial. Customarily, the surgical route to remove chordoid glioma is transcranial; however, the undersurface of the optic chiasm and optic nerves preclude an adequate surgical visualization. In contrast, an expanded endoscopic transnasal approach provides a direct midline corridor to this region without any brain retraction.

Chordoid Glioma of Third Ventricle With an Epidermoid Cyst: Coexistence or Common Histogenesis?

Chordoid glioma (CG) is a World Health Organization classified grade II tumor located exclusively in the region of anterior third ventricle. Association of CG with other lesions is extremely rare. We report a case of CG in a 45-year-old male coexisting with an epidermoid cyst in the third ventricle. Ultrastructural examination of the CG revealed microvilli, junctional complexes, and intermediate filaments within the cytoplasm suggesting origin from specialized ependyma. The association of the 2 lesions appears coincidental as convincing evidence for a common histogenesis was not found.

Prognostic factors for recurrence and complications in the surgical management of primary chordoid gliomas: A systematic review of literature

OBJECTIVE

Chordoid gliomas (CG) are rare neoplasms which frequently arise within the third ventricle. Surgery remains the mainstay treatment for CG. The present study comprehensively reviews all reported cases of CG within the literature in order to identify risk factors for surgical complications and tumor recurrence.

METHODS

A comprehensive search on MEDLINE (OVID and PubMed), Scopus, Embase, and Web of Science was conducted following PRISMA guidelines to identify all reported cases of CG.

RESULTS

A total of 81 patients met the study criteria which comprised of 33 males and 48 females. Median age at diagnosis was 48 years with a range from 5 to 72 years, and mean tumor size was 3.1cm. Biopsy, subtotal resection (STR), and gross total resection (GTR) were achieved in 8, 34, and 33 patients, respectively, with six cases not reporting extent of resection (EOR). Thirteen patients underwent adjuvant radiotherapy. Postoperative complications were noted in 30 cases (37%), with new onset diabetes insipidus being the most common. Postoperative morbidity was not associated with age, tumor size, or extent of resection. A trans-lamina terminalis approach demonstrated a strong trend towards decreased overall rates of postoperative morbidity compared to other approaches (p=0.051). GTR was associated with improved progression-free survival (PFS; p=0.028), while adjuvant radiotherapy, age, tumor size and proliferative index were not predictive of patient outcomes.

CONCLUSION

GTR should be the primary goal for the management of CG, as it is associated with improved rates of tumor control without an increased rate of postoperative complications. Surgical approach was a stronger predictor of complication rates than extent of resection. Morbidity remains high, and future studies to further elaborate on factors predictive of postoperative complications are critical.

Chordoid glioma of the third ventricle: four cases including one case with papillary features

Chordoid glioma is a rare, slowly growing tumor of the CNS, which is always located in the third ventricle of adults. Chordoid glioma has classic histological features consisting of clusters and cords of epithelioid tumor cells embedded within a mucinous stroma with rich lymphoplasmacytic infiltrate. The important distinctive immunohistochemical feature of this neoplasm is strong and diffuse reactivity for GFAP. Here, we report four cases of chordoid glioma that occupied the anterior portion of the third ventricle or suprasellar region. These four cases were all adult females with almost typical clinical, radiological, histologic and immunohistochemical characteristics of chordoid glioma. However, in one case there was an unusual histologic finding with regard to the papillary region. In this region, elongated tumor cells were observed radiating toward a central vessel to form characteristic papillary structures. Immunohistochemically, three cases showed strong reactivity for GFAP, and one exhibited weak reactivity. All cases were focally positive for epithelial membrane antigen, CD34 and D2-40, but negative for neurofilament protein (NFP). Several ultrastructural investigations have supported the ependymal origin of chordoid glioma. In some cases of immunoreactivity for NFP, some authors have supposed that chordoid glioma originates from a multipotential stem cell with glial and neuronal cell differentiation. With regard to the present four cases with immunoreactivity for D2-40 (an ependymal marker) and CD34 (undifferentiated neural precursors) and based on previously published data, we considered that the majority of chordoid gliomas had an ependymal origin, and that a small minority might have originated from a multipotential stem cell having ependymal and neuronal cell differentiation.

Chordoid glioma in suprasellar location with extension into the third ventricle: smear preparation morphology of a rare tumor

We report a rare case of recurrent chordoid glioma in suprasellar region with extension into the third ventricle diagnosed peroperatively. On MRI, a brilliantly contrast enhancing lesion in the suprasellar region extending superiorly into the third ventricle and measuring 2.5 × 3 × 3.5 cm was identified. Patient had a previous history of subtotal removal of the tumor 8 months back and had received 56 Gy of postoperative radiotherapy. On smear preparation the tumor was composed of cells arranged in chords and rows in a myxoid background with sprinkling of lymphocytes. The individual cells were polygonal with moderate amount of faintly eosinophilic cytoplasm with cytoplasmic vacoules in few cells. The nuclei showed fine chromatin with small prominent nucleoli. Paraffin sections confirmed the diagnosis and on immunohistochemistry the tumor cells showed strong positivity for GFAP and focal weak positivity for EMA with low MIB-1 labeling index (<1%). To the best of our knowledge this is the first documented case of chordoid glioma described on crush cytology.

Chordoid glioma: ten years of a low-grade tumor with high morbidity

We report two new cases of chordoid glioma of the third ventricle and review all previously published cases of this rare tumor with regard to presentation, optimum management, and outcome. Two new cases are reported with the radiological and histopathologic findings. We searched and cross-referenced PubMed and published reports of this tumor to retrieve an additional 51 cases of this tumor, which were then analyzed according to a proforma. Chordoid glioma has consistent radiological features, although some atypical elements including a cystic component are well described. The insidious presentation and morbidity of attempted surgical resection combine to give high overall morbidity. There is a high incidence of postoperative thromboembolic disturbance. Adjuvant radiosurgery has a promising role. The morbidity of this condition is likely to remain high but may be minimized by a less aggressive surgical approach together with surveillance and early use of radiosurgery.

Chordoid glioma : a case report of unusual location and neuroradiological characteristics

Since the World Health Organization (WHO) classification for central nervous system neoplasms was declared in 2000, chordoid glioma of the third ventricle has been noted as a newly recognized tumor for central nervous system neoplasms. Although there is not enough universal experience to know the nature of this tumor due to its rarity, the origin of chordoid glioma was guardedly proposed to be the ependymal cells of the third ventricle. Such an idea has been primarily based on the specific location of the tumor, that is, third ventricle, suprasellae, and hypothalamus. However, we report a rare case of histologically confirmed chordoid glioma located in the left thalamus, not attached to any of the midline structures having unusual neuroradiological characteristics.

Tanycytic ependymoma of the spinal cord with anaplastic cytological features

In a 43-year-old man, an intramedullary spinal cord tumor spreading from the level of the T2 to T5 vertebrae was subtotally resected. The tumor predominantly consisted of a fascicular proliferation of spindle cells having bland nuclei and bipolar, long cytoplasmic processes, and a few perivascular pseudo-rosettes were found. Although there were no true ependymal rosettes, intracytoplasmic dot-like immunoreactivity for epithelial membrane antigen (EMA) was found in a few cells. In some areas, a dense and diffuse proliferation of anaplastic, short-spindled cells having hyperchromatic nuclei and scant cytoplasm was noted, and the Ki-67 labeling index was remarkably higher (18.2%) in these areas. Neither microvascular proliferation nor necrosis was observed. In the boundary region, these two areas showed gradual transition from one to the other. The patient has remained free from recurrence for 10 months postoperatively. This is the first documentation of tanycytic ependymoma in which tumor cells showed anaplastic cytological features.

Papillary tumor of the pineal region: report of a rapidly progressive tumor with possible multicentric origin

Papillary tumor of the pineal region (PTPR) is an uncommon tumor recently added to the WHO classification of CNS tumors. We report a case of PTPR in a young boy that was noteworthy for early CSF dissemination and relentless progression. In spite of intensive chemotherapy and comprehensive radiotherapy, the boy died. The neuroimaging appearance is unique with possible multicentric origin of the tumor and intense uptake of (111)In-DTPA-pentetreotide.

Chordoid glioma of the third ventricle

BACKGROUND

Chordoid glioma is a rare tumour (World Health Organisation grade II) originating from the third ventricle with both glial and chordoid features. It was first described by Brat in 1998. Since there is no detailed information available on the outcome after surgery and adjuvant treatment, we reviewed the literature.

METHODS

A literature search through PUBMED revealed 50 cases of chordoid glioma. Most reports were found in pathology journals. Information on the postoperative course was sometimes very limited. We reviewed the available literature and studied in detail the presenting symptoms, mortality and postoperative complications in relation to the extent of resective surgery, as well as the importance of adjuvant treatment.

CONCLUSIONS

Mortality in the immediate postoperative period is 32% and is higher after gross total resection as compared to subtotal resection. Non-fatal postoperative complications are hypothalamic disorders and mental alterations. Gross total resection is the treatment of choice since no recurrence has been reported after macroscopically complete resection, but this is often difficult because of the location and adherence to the hypothalamus. The role of postoperative radiotherapy is uncertain. There is some indication that radiosurgery with or without conventional irradiation is superior to conventional radiation alone. Planned subtotal resection followed by stereotactic radiosurgery can be a safe and effective alternative in a patient in whom gross total resection is considered to be too risky. There is no report on the use of chemotherapy in the treatment of chordoid gliomas. More information about the optimal treatment strategy is needed, and more reports are also needed.

Chordoid glioma: a case report and molecular characterization of five cases

Chordoid gliomas are rare, slow-growing neoplasms of the anterior third ventricle. We reported a case of chordoid glioma in a 41-year-old man with obstructive hydrocephalus. Histologically, the tumor consisted of polygonal epithelioid cells admixed with elongated cells in a myxoid stroma. A prominent lymphoplasmacytic infiltrate was present. The tumor cells expressed glial fibrillary acidic protein (GFAP), epithelial membrane antigen (EMA), vimentin, CD31, CD34, epidermal growth factor receptor (EGFR) and S100 but were negative for pankeratin and E-cadherin. The percentage of Ki67 positive cells was approximately 3%. Weak p53 immunoreactivity was seen in less than 10% of the cells. Array comparative genomic hybridization performed on this case, as well as on four other archived cases, showed losses at several loci. Fluorescence in situ hybridization (FISH) confirmed consistent genetic alterations at 9p21 and 11q13. These are the fifth through ninth reported cases of chordoid gliomas with molecular characterization suggesting a distinct genetic origin from other gliomas.

Chordoid glioma of the third ventricle attached to the optic chiasm. Successful removal through a trans-lamina terminalis approach

Chordoid glioma of the third ventricle constitutes a rare, very recently recognized histological entity. Most reports of this neoplasm, focused on its distinct histological features, have hypothesized about a probable origin of the lesion at the third ventricle floor and/or the lamina terminalis. We report on a new case, presenting neuroradiological and intraoperative pictorial evidences of the tumoral attachment, limited to the chiasm-lamina terminalis junction. A 53-year-old woman debuted with acute symptoms of obstructive hydrocephalus, visual disturbances and confusion. MRI investigation showed a large solid-cystic third ventricle mass bulging through the lamina terminalis and ventricular floor. After placing a ventriculoperitoneal shunt, the tumor was completely removed through a trans-lamina terminalis approach. A tight tumoral attachment to the junction of the posterior chiasm to the lamina terminalis was identified and dissected. No other adhesions to the third ventricle boundaries were found. A chordoid glioma was diagnosed on histological examination. One year after the surgical procedure the patient does not present new neurological deficits, and there are no signs of tumoral regrowth on the follow-up postoperative MRI. Chordoid glioma should be included in the differential diagnosis of third ventricle tumors. Preoperative neuroradiological suspicion of this lesion should alert the neurosurgeon about the presence of a tight tumoral adherence at the level of the chiasm-lamina terminalis junction. The trans-lamina terminalis approach provides a suitable route for an early control of this attachment under direct vision, allowing a safe dissection of the mass from the third ventricle.

Chordoid glioma of the third ventricle: a report of two cases, one with ultrastructural findings

Chordoid glioma, which generally occurs in adults, is a rare CNS tumor arising in the anterior part of the third ventricle. We report two cases of chordoid glioma of the third ventricle in a 42-year-old woman and a 51-year-old man, respectively. Both tumors showed essentially the same histological and immunohistochemical features; the tumors were composed of cords and nests of epithelioid, GFAP-immunoreactive cells in a mucinous stroma with lymphoplasmacytic infiltrates at the tumor periphery. Ultrastructural examination in one case revealed that the tumor cells were characterized by the presence of hemidesmosomes and associated focal basal lamina formation, intermediate junctions, microvilli and cilia, and intercellular microrosettes with microvilli. Of interest was that small blood vessels with fenestrated endothelial cells were present in the stroma. In the brain, the presence of fenestrated endothelial cells is a feature of the circumventricular organs (except the subcommissural organ), among which the organum vasculosum of the lamina terminalis is located in the anterior part of the third ventricular floor that is lined by specialized ependymal cells known as tanycytes. These findings further strengthen the hypothesis that chordoid glioma may represent a peculiar clinicopathological subtype of ependymoma (chordoid ependymoma) originating from the lamina terminalis area.

Chordoid glioma: report of two rare examples with unusual features

BACKGROUND

Chordoid glioma, a rare tumour of the third ventricle, represents a distinct clinico-pathologic entity. Thirty nine examples have been described in the literature, mostly in females and in the third ventricle. The clinical presentation is variable but they tend to occur mostly in adults. There is only one report of a chordoid glioma in a 12 year old child.

FINDING

This paper describes two examples of chordoid glioma in a seven year old female child and a 70 year old male respectively. Radiologically, the paediatric chordoid glioma was located in the juxtaventricular region in the occipital horn of the lateral ventricle and was of mixed density whereas the adult patient had a typical third ventricle location with homogenous contrast enhancement. Gross total surgical removal was achieved in both but the adult patient died post-operatively due to intra ventricular bleeding and bacterial meningitis. The younger patient is doing well at the last follow up two years post-operatively. Microscopically, both showed the classic morphology of chordoid glioma. Ultrastructural examination was suggestive of ependymal differentiation.

CONCLUSION

The younger age and unusual location are some of the rare features which need documentation and have not been described earlier. We propose that chordoid glioma is a variant of an ependymoma (WHO grade II) which arises from tanycytes and should be included in the WHO classification of brain tumors.

Chordoid glioma with calcification and neurofilament expression: case report and review of the literature

BACKGROUND

Chordoid glioma of the third ventricle is a rare type of brain tumor that was recently categorized as a novel tumor entity. Despite low-grade histologic features, the clinical outcome in reported cases was poor.

CASE DESCRIPTION

A 61-year-old woman presented to our institution with a history of syncope. On presentation, she was alert and oriented, and her systemic examination was unremarkable. Computed tomographic scan showed a well-circumscribed, slightly hyperdense mass with calcification and a cystic component in the anterior part of the third ventricle. The mass was homogenously enhancing after the intravenous administration of contrast material, and its maximum diameter was 3.5 cm. The preoperative diagnosis was craniopharyngioma. Because the tumor seemed to invade the hypothalamus bilaterally, the operative plan was to reduce the tumor volume, followed by radiosurgery. The patient underwent partial removal of the tumor via a bifrontal basal interhemispheric approach. The histologic and immunohistochemical findings indicated CG. Surprisingly, tumor cells showed NFP expression. The residual tumor was treated by GKRS and showed no regrowth at 1-year follow-up.

CONCLUSIONS

Chordoid glioma is considered a glial neoplasm with distinct morphological and clinicopathologic features, but there may also be other unknown characteristics because of its rarity. To the best of our knowledge, this is the second reported case of CG with calcification and, at the same time, the second case with NFP expression in the English literature. Calcification and expression of NFP should not exclude CG in the differential diagnosis of a third ventricular tumor. The authors also suggest that the combination of microsurgery and GKRS is a safe and effective treatment strategy for CG.

Microarray Analysis Reveals Differential Gene Expression Patterns in Tumors of the Pineal Region

Several types of tumors are known to originate from the pineal region, among them pineal parenchymal tumors (PPTs) and papillary tumors of the pineal region (PTPRs), probably derived from the subcommissural organ. As a result of their rarity, their histologic diagnosis remains difficult. To identify molecular markers, using CodeLink oligonucleotide arrays, gene expression was studied in 3 PPTs (2 pineocytomas and one pineoblastoma), 2 PTPRs, and one chordoid glioma, another rare tumor of the third ventricle. Because PTPR and chordoid glioma may present ependymal differentiation, gene expression was also analyzed in 4 ependymomas. The gene patterns of the 3 PPTs fell in the same cluster. The pineocytomas showed high expression of TPH, HIOMT, and genes related to phototransduction in the retina (OPN4, RGS16, and CRB3), whereas the pineoblastoma showed high expression of UBEC2, SOX4, TERT, TEP1, PRAME, CD24, POU4F2, and HOXD13. Using reverse transcriptase-polymerase chain reaction on 13 PPTs, we demonstrated that PRAME, CD24, POU4F2, and HOXD13 might be candidates for grading PPT with intermediate differentiation. PTPRs, classified with chordoid glioma and separately from ependymomas, showed high expression of SPEDF, KRT18, and genes encoding proteins reported to be expressed in the subcommissural organ, namely ZFH4, RFX3, TTR, and CGRP. Our results highlight the usefulness of gene expression profiling for classify tumors of the pineal region and identify genes with potential use as diagnostic markers.

Origin of chordoid glioma of the third ventricle

CONTEXT

Chordoid glioma is a relatively recently described unique glial neoplasm that has been formally codified by the World Health Organization in Pathology and Genetics of Tumours of the Nervous System, in which it is included along with astroblastoma and gliomatosis cerebri under the rubric "Tumors of Uncertain Origin." Many examples of chordoid glioma come to clinical attention only at a relatively large size and occupy a large portion of the third ventricle. Accordingly, the anatomic origin of chordoid glioma has been unclear and debated.

OBJECTIVE

To examine the regional anatomic origin of chordoid glioma.

DATA SOURCES

The clinical, imaging, histologic, immunophenotypic, and ultrastructural data in previously published case series and individual case reports of chordoid glioma were reviewed in conjunction with the study of a new case of chordoid glioma that presented at a relatively small size, thereby facilitating neuroanatomic localization.

CONCLUSIONS

Chordoid glioma exhibits features of specialized ependymal differentiation on ultrastructural examination, and all examples reported in the literature to date have displayed a highly stereotypical suprasellar anatomic localization and an ovoid shape, as seen on neuroimaging studies and gross anatomy. Neuroanatomic, radiologic, and clinical evidence supports an anatomic origin for chordoid glioma from the vicinity of the lamina terminalis.

Podoplanin is expressed in subsets of tumors of the central nervous system

Immunohistochemical analyses with the monoclonal antibody D2-40 were performed to ascertain the expression of podoplanin (a.k.a. T1-alpha, gp36, or aggrus) in tumors of the central nervous system (CNS) and to determine the diagnostic utility of the antibody. The analyses were performed on 325 tumors of various histologic types. The chief finding was almost constant immunoreactivity in ependymal tumors (37/40, 92.5%), choroid plexus papillomas (8/8, 100%), and meningiomas (100/100, 100%). The reactivity was considered "tissue-specific," as the corresponding normal tissue of each tumor was also found to express podoplanin. In addition, expression, not committed to the lineages, was found in many other tumor types, including astrocytic tumors, medulloblastomas, and hemangioblastomas, with variable frequency and intensity. The way of expression was not fully understood, but the expression in astrocytic tumors seemed to be associated with pronounced fibrous properties or malignant phenotype, as was shown by high-frequent expression in pilocytic astrocytomas (12/12, 100%) and glioblastomas (29/35, 82.9%). The present study has shown that podoplanin is expressed in several types of CNS tumors with variable frequency and intensity. Given the widespread expression of podoplanin, the antibody D2-40 is of little use in diagnostic practice for CNS tumors.

Third Ventricular Chordoid Glioma With Unusual Aggressive Behavior-Case Report-

A 50-year-old woman presented with a rare chordoid glioma manifesting as an approximately 4-year history of decreased cognitive function and recent decreased visual acuity. Magnetic resonance imaging showed a 4.5 x 3.5 cm multilobulated strongly enhanced mass in the suprasellar cistern and third ventricle associated with hydrocephalus. The tumor was subtotally removed via a transcallosal approach. Histological examination showed chordoid glioma. Two months later, ventriculoperitoneal shunting was performed for hydrocephalus. The tumor and hydrocephalus recurred after 3 months. She died after 4 months because of deepened mentality and combined pneumonia. This very short duration before recurrence suggests that neuroimaging follow up may be necessary in patients with subtotally removed choroid glioma.

Third ventricular chordoid glioma: clinicopathological study of two cases with evidence for a poor clinical outcome despite low grade histological features

Chordoid glioma of the third ventricle is a rare glial tumour whose precise histogenesis remains uncertain. We describe two cases that presented recently to our department and review the background literature. The neoplasm tends to occur in women and its clinical presentation is variable, resulting from acute hydrocephalus or impingement upon local structures. However, the radiological appearance is distinct, with an ovoid shape, hyperdensity and uniform contrast enhancement on computerized tomography and magnetic resonance imaging. Intraoperative smear diagnosis is difficult because of the lack of specific features, although the presence of metachromatic extracellular mucin may be useful. The characteristic histological appearance is that of cords and clusters of cohesive, oval-to-polygonal epithelioid cells with abundant eosinophilic cytoplasm and a mucinous background. There is often a mixed chronic inflammatory infiltrate with lymphocytes and plasma cells with Russell bodies. The main differentials for histological diagnosis include chordoid meningiomas, pilocytic astrocytomas and ependymomas. An immunohistochemical panel including antibodies to glial fibrillary acidic protein, CD 34, epithelial membrane antigen, pan cytokeratin, S100 and vimentin can be used to distinguish between these possibilities. Ultrastructurally the tumour cells have basal lamina and microvilli, reminiscent of ependymomas. The clinical outcome in our cases was poor because of the location of the lesion and its close relation to the hypothalamus. Limited follow-up after surgery with or without radiotherapy suggests that as-full-as-possible resection favours a better outcome, although surgery in this area carries significant operative risks.

Newly defined central nervous system neoplasms

In recent years, numerous new entities or variants of recognized central nervous system tumors have been described in the literature, and the morphologic spectrum of these neoplasms is delineated incompletely. The accurate diagnosis and classification of these lesions is important to ensure that patients receive adequate therapy and prognostic information. The clinicopathologic features and differential diagnosis of 4 new entities, including the chordoid glioma of the third ventricle, cerebellar liponeurocytoma, atypical teratoid/rhabdoid tumor, and papillary glioneuronal tumor, are discussed in this review.

Chordoid glioma: clinicopathologic profile and differential diagnosis of an uncommon tumor

Chordoid glioma is an uncommon low-grade brain neoplasm arising in the third ventricular region, predominantly in middle-aged women. It characteristically shows chordoma-like histologic features and glial fibrillary acidic protein immunoreactivity. We present a case of chordoid glioma in a previously healthy 56-year-old woman admitted to our hospital because of a cranial trauma subsequent to an incidental fall. Radiologic examinations revealed a well-demarcated, partially cystic, enhancing mass at the level of the lamina terminalis. The lesion was surgically removed. The patient remained alive and well 8 months after the surgery. Histologically, the tumor consisted of clusters and cords of epithelioid cells embedded in a mucinous matrix. Lymphoplasmacytic infiltrates and Russell bodies were prominent. Immunohistochemically, the tumor cells were positive for glial fibrillary acidic protein, neurofilaments, and neuron-specific enolase, suggesting a divergent neuronal and glial differentiation. The Ki-67 index was low. The clinicopathologic profile and the differential diagnosis of this tumor are discussed.

Suprasellar chordoid glioma combined with Rathke's cleft cyst

Chordoid glioma has been recently described as a slow-growing neoplasm with chordoid appearance, occurring exclusively in the regions of the third ventricle and hypothalamus of middle-aged women. We experienced a case of a 48-year-old woman with a suprasellar tumor composed of chordoid glioma and Rathke's cleft cyst, which was confirmed by histopathological, immunohistochemical and electron microscopic examinations. Histologically, chordoid glioma comprised the major part of the tumor, and the prominent Rathke's cleft cysts were distributed focally in the same tumor tissue without any transitions. Chordoid glioma was immunoreactive for glial fibrillary acidic protein, S-100 protein and vimentin, and focally positive for epithelial membrane antigen and CD34, while cytokeratin highlighted epithelial cells lining Rathke's cleft cysts. Ultrastructural examination of the chordoid glioma revealed short cytoplasmic processes, intermediate filaments, intercellular junctions of zonular adherens type, basal lamina, secretory granules and pinocytic vesicles. The ultrastructural observations of the current case are similar to those of the subcommisural organ, although cell body zonation or microvilli were not evident. The coexistence of chordoid glioma and Rathke's cleft cyst has not been reported previously and may represent a collision tumor.

Emerging Tumor Entities and Variants of CNS Neoplasms

Since the appearance in 2000 of the World Health Organization (WHO) classification for central nervous system (CNS) neoplasms, numerous descriptions of new entities or variants have appeared in the literature. In the group of neuronal and mixed glioneuronal neoplasms are lesions with distinctive morphological features that are still not included in a precise classification, including extraventricular neurocytoma, papillary glioneuronal tumor, rosette-forming glioneuronal of the fourth ventricle, glioneuronal with neuropil-like rosette, and DNT-like tumor of the septum pellucidum. The glioneuronal tumor with neuropil-like rosette and oligodendroglioma with neurocytic differentiation represent morphological variants of genetically proven diffuse gliomas. The lipoastrocytoma and the pilomixoid astrocytoma enlarge the group of astrocytic lesions. Rare, low-grade gliomas of the spinal cord with extensive leptomeningeal dissemination associated with unusual neuroimaging are described. The chordoid glioma of the third ventricle and the papillary tumor of the pineal region seem to be correlated by a common histogenesis from the specialized ependyma of the subcommissural organ. An embryonal tumor with neuropil and true rosettes combining features of neuroblastoma and ependymoblastoma is discussed. These new, recently described lesions indicate that the complex morphologic spectrum of CNS tumors is far from being completely delineated.

Chordoid glioma: report of a case with unusual histologic features, ultrastructural study and review of the literature

Chordoid gliomas are an uncommon primary brain tumor with histologic features of a chordoma and immunolabeling for glial fibrillary acid protein. We report the 32nd case with a review of the literature. The clinical, radiographic and pathologic features of the tumor are presented with new pathologic findings adding support that this lesion may be of ependymal origin. Treatment and long term outcome are limited but chordoid gliomas appear to be indolent lesions that may be cured with gross total resection.

Third ventricular chordoid glioma: case report and review of the literature

BACKGROUND

Chordoid glioma of the third ventricle is a rare type of brain tumor that was recently characterized as a novel tumor entity. We present a case and review of the literature.

CASE REPORT

A 49-year-old woman presented with progressive headache, memory impairment and urinary incontinence. MRI showed a large well-circumscribed tumor in the third ventricle. The tumor was partially removed via a trans-lamina terminalis approach. The histologic findings indicated chordoid glioma. Residual tumor was treated by stereotactic radiosurgery and showed no regrowth at 2-year follow-up.

CONCLUSIONS

The ideal therapy is total removal of the tumor. However, according to the literature, total removal of the tumor carries a high risk because of its location, and conventional radiation therapy has little effect on the residual tumor. On the other hand, stereotactic radiosurgery appears more promising, and to date, no regrowth has been reported after gamma-knife therapy.

Papillary tumor of the pineal region

Primary papillary tumors of the central nervous system are rare. We have encountered a series of six papillary tumors of the pineal region with distinctive features that appear to represent a clinicopathologic entity. The tumors occurred in four women and two men, ranging in age from 19 to 53 years. Imaging studies showed a large well-circumscribed mass in the pineal region. The tumors were characterized by an epithelial-like growth pattern, in which the vessels were covered by a layer of tumoral cells. In papillary areas, the neoplastic cells were large, columnar or cuboidal, with a clear cytoplasm. Nuclei, round or infolded, were found generally at the basal pole of tumoral cells. Immunohistochemically, the tumor cells showed strong staining for cytokeratin, S-100 protein, neuron-specific enolase, and vimentin but only weak or no staining for epithelial membrane antigen and glial fibrillary acid protein. Ultrastructural examination of two cases revealed abundant rough endoplasmic reticulum with distended cisternae filled with secretory product, microvilli, and perinuclear intermediate filaments. The morphofunctional features of these papillary tumors of the pineal region, remarkably uniform within this series, are similar to those described for ependymal cells of the subcommissural organ, and the papillary tumors of the pineal region may be derived from these specialized ependymocytes.

The Big Eye in the 21st century: the role of electron microscopy in modern diagnostic neuropathology

Electron microscopy (EM) remains a powerful and even essential tool in modern diagnostic neuropathology. tumors are still encountered that defy histological or immunohistochemical classification, and EM can often provide answers in these cases. Tumors of the CNS for which EM is useful include unusual or atypical variants of meningioma, ependymoma, and schwannoma; oligodendroglioma-like tumors composed of small "clear" cells; and small "blue cell" tumors of childhood. EM is of great value in identifying site of origin for metastatic adenocarcinomas of unknown origin-an under-recognized and under-utilized potential for this technique. EM is useful in the diagnosis of peripheral nerve sheath tumors and gastrointestinal autonomic nerve tumors. EM is also important in the evaluation of certain congenital, inherited and metabolic diseases-including ceroid lipofuscinoses, CADASIL syndrome, certain myopathies, and mitochondrial encephalomyopathies--and of certain toxic and drug-induced peripheral neuropathies. An important application of EM is its utility in initiating a workup of an atypical tumor or metabolic condition, for which clinical and histological clues point in no obvious direction. In these situations, EM may provide either an answer outright (including answers to questions not asked) or important clues that guide further workup and narrow the range of diagnostic possibilities.

Chordoid glioma of the third ventricle: a report of two new cases, with further evidence supporting an ependymal differentiation, and review of the literature

The term chordoid glioma of the third ventricle was first used to describe a rare and slowly growing neoplasm of uncertain histogenesis, with chordoid appearance, occurring preferentially in middle-aged women. Herein we report two additional examples of this novel entity together with a literature review based on the 25 cases previously published. Our review fully confirms the strikingly stereotyped clinical, neuroradiologic, and pathologic features of this unique tumor. The female/male ratio was 1.7:1, and the age range was 24-70 years (mean 44.9 years). In all 27 cases imaging findings were similar showing a well-defined mass (mean 2.8 cm in largest dimension), ovoid in shape, hyperdense on CT scans, with uniform and intense contrast enhancement, arising in the hypothalamic/suprasellar/third ventricular region. Histologically, the main consistent characteristics were cords and clusters of epithelioid cells within an abundant mucinous and often vacuolated background. Mitoses were sparse or absent and anaplastic features, endothelial proliferation, and necrosis were not identified. Lymphoplasmacytic infiltrates with Russell bodies were frequent throughout the tumor and its interface with adjacent brain parenchyma. Most of the tumor cells revealed a strong and diffuse expression of vimentin and glial fibrillary acidic protein. Additionally, the vast majority of tumors showed focal coexpression of cytokeratins, CD34, S-100 protein, and epithelial membrane antigen; the MIB-1 labeling indices were uniformly low. Surprisingly for a glioma assigned WHO grade II, the 19 patients with an available but short follow-up (mean 22.5 months; range 6-68 months) experienced a rather poor outcome (three recurrences and seven deaths), probably reflecting the anatomic site of the neoplasm that precludes a complete surgical excision rather than its histologic composition. Ultrastructural examination of 10 cases demonstrated findings in line with a glial derivation and a putative ependymal origin such as cytoplasmic intermediate filaments, microvilli, intermediate junctions or desmosomes, and focal basal lamina formation. In our case no. 1, and for the first time in this tumor, we observed sparse and abnormal cilia in an aberrant juxtanuclear location, a further argument for considering chordoid glioma as a subtype of ependymoma. However, a better understanding of the biologic behavior and histogenesis of this distinctive clinicopathologic entity needs to be investigated with a larger series. Nevertheless, taking into account its strikingly consistent anatomic localization, its unique histopathologic and immunohistochemical profile, in conjunction with the most recent and convincing ultrastructural arguments, we suggest that chordoid glioma of the third ventricle could be better classified as chordoid ependymoma of the lamina terminalis area.