Chordomas—ultrastructure and immunohistochemistry: a report based on the examination of six cases

Six chordomas (three classic and three chondroid) were examined ultrastructurally and with a panel of monoclonal antibodies. The three classic tumours showed the presence of desmosomes and intermediate filaments on electron microscopy, findings which gave a direct positive correlation when the tumours were stained with monoclonal antibodies against low molecular weight cytokeratin proteins. These results suggest that chordomas are essentially epithelial neoplasms and underline the fact that monoclonal antibodies to cytokeratins cannot be used in the differential diagnosis of classic chordoma vs carcinoma. Furthermore, the epithelial characteristics are lost as the tumour undergoes chondroid differentiation.     

大鼠脑内大分子物质的引流通路及方法学研究

为探讨脑内大分子物质的引流通路,本研究微量注射示踪剂墨汁到大鼠右侧尾壳核,Ⅰ组动物使用传统的脑内注射方法,Ⅱ组动物采取改良方法防止示踪剂从进针处进入蛛网膜下腔,术后1、3、7、14、21 d处死动物,分别用肉眼、光镜及电镜观察墨汁在脑内、蛛网膜下腔、颈总动脉及颈部淋巴结的分布。结果显示:墨汁在两组动物脑实质内的分布趋势相同,即在白质内沿神经纤维弥漫性分布,7 d后在灰质内选择性地沿血管周围间隙分布,部分碳颗粒被管周细胞和巨噬细胞吞噬;Ⅱ组动物中观察到墨汁从大脑顶部进入蛛网膜下腔后沿其中的血管周围间隙分布并引流到脑的底部和嗅球及筛板区域,在耳蜗、前庭蜗神经和视神经等的脑神经鞘以及颈总动脉壁和颈部淋巴结有碳颗粒沉积;Ⅰ组动物没有这种分布。以上结果表明,大鼠脑实质内的大分子物质在白质和灰质中的引流方式不同;进入脑脊液的大分子物质可由颈部淋巴系统引流;墨汁不是很好的研究脑实质内大分子物质引流的示踪剂。     

太空飞行神经眼综合征的生物力学因素研究进展

长期太空飞行可导致航天员眼部解剖结构改变并产生相应的视力受损,这种现象被定义为太空飞行相关神经眼综合征(SANS)。SANS是人类长期太空飞行眼部面临的最重要的问题,其发病机理尚未阐明,阻碍了有效防护措施的开发,也无法建立个体易感性评估指标,用于建立相应的航天员遴选标准。SANS与微重力环境下视神经蛛网膜下腔脑脊液压升高有关,但详细的作用机制和相应的对抗措施尚不明确。首先对SANS导致的视盘、眼后节、蛛网膜下腔和视神经的形态学变化进行了总结,随后就当前学界提出的SANS发病机理、影响SANS易感性因素以及应对措施进行了综述,并总结了SANS与微重力环境下视神经蛛网膜下腔脑脊液压力的关系,最后对如何将地基实验与天基实验有效结合来深入探索SANS的发病机制进行了展望。     

视神经和视交叉冠状断层解剖与MRI

目的：研究视神经和视交叉在冠状断面上的解剖特征与MRI表现,为相关疾病的影像诊断和外科手术提供解剖学资料。方法：选取15例成人尸头标本,以冷冻切片法切制成连续冠状断层标本;应用3．0TMRI扫描仪,获取10例志愿者头部的sE序列T1WI和T2WI图像;在上述断层标本和MRI图像上,观察分析冠状断面上视神经的形态、位置和毗邻关系。结果：视神经眶内段居于眶中心偏内上方,断面呈圆形,其周围有视神经鞘包绕,蛛网膜下隙清晰可见,眼动脉位于其上方;视神经管内段居于眶内上方,断面呈水平卵圆形,周围可见视神经鞘,蛛网膜下隙不明显,眼动脉位于其下方;视交叉冠状断面呈“一”字型,分隔上方的视隐窝和后下方的漏斗隐窝,其上方有大脑前动脉A1段,下方为灰结节和垂体柄。结论：冠状断面町以清楚显示视神经、视交叉的形态特点与毗邻关系。     

Parapharyngeal chordoma: A diagnostic challenge and potential mimic of pleomorphic adenoma on fine‐needle aspiration cytology

Chordomas are rare tumors that are usually located in the sacrococcygeal and sphenooccipital region. Their cytologic diagnosis is rather straightforward when sampled by fine‐needle aspiration (FNA) from these characteristic locations, especially when physalipherous cells are present. However, chordomas may pose difficult diagnostic challenges when encountered in unusual locations, such as the parapharyngeal region. We report the cytologic findings of a recurrent chordoma sampled through transoral FNA from the parapharyngeal space of a 66‐year‐old woman. As the prior history of chordoma was not available during the rapid onsite evaluation, the presence of bland epithelioid nonvacuolated cells and spindle cells intimately admixed with a fibrillary, intensely metachromatic material led to an initial diagnosis of pleomorphic adenoma. Review of the patient's prior pathology specimen and of the Papanicolaou‐stained smears and cellblock sections showing rare multivacuolated (physalipherous) cells led to the correct diagnosis, which was supported by immunoperoxidase stains (cytokeratin AE1/AE3+, S100+, GFAP?). A review of the literature found no previous instances in which chordomas mimicked pleomorphic adenoma on FNA. However, since the two tumors show significant cytomorphologic overlap, including the presence of abundant fibrillary matrix with embedded neoplastic cells and single bland spindle and epithelioid tumor cells with occasional intranuclear pseudoinclusions, we compared their cytologic features. A review of the FNA cytologic features of this case of chordoma and of 17 consecutive cases of pleomorphic adenoma found that the presence of a more abundant, focally vacuolated cytoplasm favors chordoma over pleomorphic adenoma. Diagn. Cytopathol. 2013. © 2011 Wiley Periodicals, Inc.     

AN UNUSUAL CASE WHICH BEGAN WITH SUBCUTANEOUS PANNICULITIS FOLLOWED BY FEVER, SEVERE HEPATIC INVOLVEMENT AND HYPERLIPIDEMIA

A 25-year-old man was at first dermatologically suspected as suffering from Weber-Christian syndrome because of subcutaneous panniculitis, but his skin lesions disappeared completely during the course. Hyperlipidemla, disturbances In liver function, and leukemoid reaction became remarkable, and he died of subarachnoid hemorrhage eleven months after onset. Necropsy revealed subarachnoid hemorrhage at the base of the brain, lipogranulomatous and inflammatory lesions in the upper lobe of the left lung, a remarkable fatty liver, splenomegaly, pericarditis, and foam cells in the spleen, liver, and bone marrow. A comparison with 57 autopsy cases of Weber-Christian syndrome reported in the literature showed our case to be an exceptional instance of Weber-Christian syndrome, If the present case is not to be regarded as a different disease entity. ACTA PATH. JAP. 27:213–224, 1977.     

Cytogenetic investigation of chordomas of the skull.

We report the first cytogenetic investigation of cranial chordoma. Three cranial chordomas were examined, two of which could be further histopathologically classified as chondroid chordomas. In addition, we have included a case of chordoma of a cervical vertebra to compare the cytogenetic abnormalities. Diagnosis was made at histological and immunohistochemical levels. The three cases of cranial chordoma showed a normal karyotype, while one vertebra showed 46,XY,t(6;11)(q12;q23). Chordomas, particularly those containing cartilage, have to be distinguished from chondrosarcomas of the skull base. Such a distinction is normally based on expression of epithelial markers which usually are lacking in chondrosarcoma. Cytogenetic investigation may eventually prove to be useful in the distinction of the two lesions, if chromosome anomalies are consistently absent in chordoma, although some chondrosarcomas may also present a normal karyotype. Such a distinction has clinical implications because chondroid chordomas show better survival, whereas chondrosarcomas show a propensity to infiltrate the surrounding tissues.     

Expression of c-MET, low-molecular-weight cytokeratin, matrix metalloproteinases-1 and -2 in spinal chordoma

Aims:  In skull base chordoma, c-MET expression has been reported to correlate with younger patient age and favourable prognosis; however, it also contributes to tumour invasiveness, especially in recurrent lesions, suggesting variable roles for c-MET according to clinical status. The aim of this study was to investigate the significance of c-MET expression in spinal chordoma, which affects patients who are 10–20 years older than those with skull base chordoma.
Methods and results:  Using immunohistochemical techniques, the expression of c-MET and its ligand, hepatocyte growth factor (HGF) was investigated in 34 primary spinal chordomas and compared with other clinicopathological parameters. Expression of c-MET and HGF was observed in 85.3 and 21.7% of lesions, respectively. c-MET expression correlated with the expression of an epithelial marker, low-molecular-weight cytokeratin (CAM5.2). Lesions with higher c-MET expression showed significantly stronger expression of proteinases, including matrix metalloproteinase (MMP)-1 and MMP-2. However, c-MET expression was not associated with patient age, proliferative ability estimated by MIB-1 labelling index, or prognosis.
Conclusions:  c-MET expression was observed in most spinal chordomas and correlated with the expression of CAM5.2, suggesting a relationship to an epithelial phenotype.     

Man with posterior fossa tumors 15 years apart

A 48-year-old man with a history of hypertension, peripheral vascular disease and a 50-pack-year history of smoking presented with new onset vertigo, tinnitus, diplopia and ataxia in January 1978. CT scan showed a radiolucent defect in the left cerebellar hemisphere with a possible mural nodule. In ensuing months, he experienced worsening symptoms with a corresponding increase in lesion size on re-imaging. Months later, a left posterior fossa craniotomy was performed and revealed a single cystic lesion containing copious amounts of straw-colored fluid and a single mural nodule in the inferior portion of the cyst. Following resection, he was followed clinically until 1985 at which time follow-up was discontinued. He did well until January 1993 when he presented with progressively worsening episodic headaches and retro-orbital pressure. Subsequent MRIs of the brain and spine (February 1993, March 1993) showed multiple lesions along the neuraxis involving the superficial brain parenchyma, leptomeninges, and dura. Despite therapy, his condition progressively declined until he succumbed. A brain-only autopsy revealed numerous small tumor nodules involving the base of the brain over both frontal and temporal lobes, midbrain, pons, right optic nerve, pituitary fossa, and the base of the skull. Pathologic evaluation revealed metastatic hemangioblastoma. Metastatic hemangioblastoma is a rare entity, with only a few reported cases in the literature to date.     

Aquaporin-4 in brain and spinal cord oedema

Brain oedema is a major clinical problem produced by CNS diseases (e.g. stroke, brain tumour, brain abscess) and systemic diseases that secondarily affect the CNS (e.g. hyponatraemia, liver failure). The swollen brain is compressed against the surrounding dura and skull, which causes the intracranial pressure to rise, leading to brain ischaemia, herniation, and ultimately death. A water channel protein, aquaporin-4 (AQP4), is found in astrocyte foot processes (blood–brain border), the glia limitans (subarachnoid cerebrospinal fluid—brain border) and ependyma (ventricular cerebrospinal fluid—brain border). Experiments using mice lacking AQP4 or alpha syntrophin (which secondarily downregulate AQP4) showed that AQP4 facilitates oedema formation in diseases causing cytotoxic (cell swelling) oedema such as cerebral ischaemia, hyponatraemia and meningitis. In contrast, AQP4 facilitates oedema elimination in diseases causing vasogenic (vessel leak) oedema and therefore AQP4 deletion aggravates brain oedema produced by brain tumour and brain abscess. AQP4 is also important in spinal cord oedema. AQP4 deletion was associated with less cord oedema and improved outcome after compression spinal cord injury in mice. Here we consider the possible routes of oedema formation and elimination in the injured cord and speculate about the role of AQP4. Finally we discuss the role of AQP4 in neuromyelitis optica (NMO), an inflammatory demyelinating disease that produces oedema in the spinal cord and optic nerves. NMO patients have circulating AQP4 IgG autoantibody, which is now used for diagnosing NMO. We speculate how NMO-IgG might produce CNS inflammation, demyelination and oedema. Since AQP4 plays a key role in the pathogenesis of CNS oedema, we conclude that AQP4 inhibitors and activators may reduce CNS oedema in many diseases.     

RETINOBLASTOMA WITH INTRACRANIAL EXTENSION - AN AUTOPSY CASE WITH LIGHT AND ELECTRON MICROSCOPE

A case of a 6-year-old girl with unilateral retinoblastoma with widespread dissemination into the subarachnoid space through the optic nerve is reported. The enucleated right eye showed advanced tumor growth characterized by exo- and endophytic invasion. The growth infiltrated through the lamina cribrosa and directly into the substance of the optic nerve. Extension into the central nervous system was through the optic nerve. The tumor consisted of only anaplastic cells and showed no tendency of rosette formation. Electron micrographs of the surgical specimen and necropsy material fixed with formalin suggested that tumor cells may be of primitive and anaplastic without any differentiation to glial or neuronal cells. The tumor is consistent with udnifferentiated retinoblastoma previously reported by Reese et al.     

Fine-needle aspiration cytology with histological correlation of chordoma metastatic to the lung: a diagnostic dilemma

Chordoma is an uncommon tumor initially believed to be benign due to the rarity of its metastasis. Cytological, morphological, and immunohistochemical features of chordoma, relating to its origin from notochordal remnants, allows for its accurate diagnosis. A 75-year-old man with a known history of tuberculosis (TB) presented with shortness of breath and a dry cough. A chest X-ray demonstrated a diffuse, infiltrative miliary pattern in both lungs. Bronchial washings submitted for culture and cytological examination did not identify any tuberculous bacilli. Fine needle aspiration cytology (FNAC) showed focal areas of myxoid regions with small, round, uniform mononuclear cells. There was a documented past history of chordoma arising from the L2 vertebrae. Because of the rarity of this lesion in the lung and the limited diagnostic material available with a clinical history of TB and lumbar chordoma, the pathological report rendered on the FNAC was "atypical cells suspicious for metastatic chordoma." A wedge biopsy of the lung confirmed the presence of metastatic pulmonary chordoma. Despite palliative treatment, he died within a year. Although the metastatic potential of chordomas has been recognized and documented, to the best of our knowledge, metastasis of chordoma to the lung diagnosed by FNAC with cytohistological correlation has not been previously reported in the English literature.     

Postmortem image analysis of sheep cortical leptomeningeal space and vasculature: theoretical implications on brain surface dialysis

The vascular surface distribution of the subarachnoid space has not been studied extensively. The aim of our study was to develop a method of computer-assisted estimation of the distribution of the vascular network in the cortical leptomeninges and subarachnoid space and model it to aid the study of the physiology of brain surface dialysis. Nine sheets of leptomeningeal tissue were obtained from adult sheep. Fourteen image sample areas of 4 cm2 each were acquired and processed with ImageJ. The vascular and nonvascular areas of the cortical subarachnoid space were identified using a "projected surface" approach. The modeling equations were used to predict the behavior of brain surface dialysis processes. The mean surface area of identified subarachnoid vessels was 0.354 ± 0.02 cm2 per 1 cm2 of tissue. The mean meningeal area with unidentified vessels was 0.646 ± 0.02 cm2/1 cm2, and the difference between these surfaces was significant (p < 0.0001). The modeling equations used predict that modifying the vessel diameter of the subarachnoid space could alter the efficiency of brain surface dialysis. The computer-assisted modeling of the vascular surface of the cortical subarachnoid space may be a useful tool in depicting its morphology and assessing the physiology during brain surface dialysis.     

Collagenous and basement membrane proteins of chordoma: immunohistochemical analysis

Tissue localization of collagenous and basement membrane proteins in the extracellular matrix of five sacro-coccygeal chordomas and human fetal notochords was examined immunohistochemically to assess the implications for the histogenesis and histological diagnosis of chordoma. Human fetal notochords and conventional chordomas both exhibited basement membrane proteins (such as type IV collagen and laminin) and type VI collagen on the surfaces of cellular cords. Type II collagen, a main structural protein of cartilage, was also present in both tissues. In the chordomas, however, type II collagen was not so widespread as it was in the notochords, and the predominant collagenous protein was type I. In contrast, an altered deposition of these proteins was noticed in a recurrent tumour which, histologically, showed considerable atypia and eventually metastasized to the liver. The characteristic cartilage-type and basement membrane proteins disappeared and unusual collagen types, such as types III and V, appeared in the stroma. The results further support the notochordal origin of chordoma and suggest that the immunohistochemistry of collagenous and basement membrane proteins may be a helpful criterion for the histological diagnosis and prediction of the biological aggressiveness of chordomas.     

The translaminar pressure gradient in sustained zero gravity,idiopathic intracranial hypertension,and glaucoma

Papilledema has long been associated with elevated intracranial pressure. Classically, tumors, idiopathic intracranial hypertension, and obstructive hydrocephalus have led to an increase in intracranial pressure causing optic nerve head edema and observable optic nerve swelling. Recent reports describe astronauts returning from prolonged space flight on the International Space Station with papilledema (Mader et al., 2011) [1]. Papilledema has not been observed in shorter duration space flight. Other recent work has shown that the difference in intraocular pressure (IOP) and cerebrospinal fluid pressure (CSFp) may be very important in the pathogenesis of diseases of the optic nerve, especially glaucoma (Berdahl and Allingham, 2009; Berdahl, Allingham, et al., 2008; Berdahl et al., 2008; Ren et al., 2009; Ren et al., 2011) [2], [3], [4], [5], [6]. The difference in IOP and CSFp across the lamina cribrosa is known as the translaminar pressure difference (TLPD).We hypothesize that in zero gravity, CSF no longer pools in the caudal spinal column as it does in the upright position on earth. Instead, CSF diffuses throughout the subarachnoid space resulting in a moderate but persistently elevated cranial CSF pressure, including the region just posterior to the lamina cribrosa known as the optic nerve subarachnoid space (ONSAS). This small but chronically elevated CSFp could lead to papilledema when CSFp is greater than the IOP. If the TLPD is the cause of optic nerve head edema in astronauts subjected to prolonged zero gravity, raising IOP and/or orbital pressure may treat this condition and protect astronauts in future space travels from the effect of zero gravity on the optic nerve head. Additionally, the same TLPD concept may offer a deeper understanding of the pathogenesis and treatment options of idiopathic intracranial hypertension (IIH), glaucoma and other diseases of the optic nerve head.     

Immunohistochemical analysis of E-cadherin, α-catenin, ß-catenin, γ-catenin, and neural cell adhesion molecule (NCAM) in chordoma

AIMS: The epithelioid features seen in chordoma are unique among mesenchymal tumours. However, no detailed analysis regarding cell-cell communication has been conducted in this epithelioid tumour. The aims of this study were to investigate cell-cell communication in chordoma. METHODS: By means of immunohistochemical techniques that incorporated a panel of monoclonal antibodies against cell adhesion molecules (CAMs), including E-cadherin, alpha-catenin, beta-catenin, gamma-catenin, and neural cell adhesion molecule (NCAM), the expression of CAMs was studied in 15 specimens of chordoma and eight specimens of chondrosarcoma. RESULTS: Most chordoma specimens showed some positive immunoreactivity for all the CAMs examined. For the various CAMs investigated, between two and five cases showed diffuse immunoreactions, indicating well preserved expression. Well preserved expression of all the CAMs examined was limited to only one case, thus indicating that the expression of CAMs was decreased in most of the chordoma specimens; however, no significant correlation was found between the decreased expression of CAMs and the histological grade of malignancy, cellular growth pattern, or clinical parameters in chordoma. In chondrosarcoma, only a few specimens showed positive immunoreactivity for CAMs and the expression of E-cadherin, beta-catenin, gamma-catenin, and NCAM was seen more frequently in the chordoma specimens than in the chondrosarcoma specimens. CONCLUSIONS: These results suggest that the expression of CAMs is associated with the formation and maintenance of chordoma tissue architecture, just as it is in other epithelial tumours or normal tissue. Immunohistochemistry for CAMs was found to be of diagnostic value for discriminating chordoma from chondrosarcoma, and these markers could be used along with the cytokeratins, which are already used for this purpose.     

Comparison of metastatic brain tumour models using three different methods: the morphological role of the pia mater

As methods of cancer diagnosis and treatment progress, interest in metastatic brain tumours continues to increase. There are many studies using various methods of animal model and we considered that each model reflects different pathological processes because of the unique composition of the brain. We prepared metastatic brain tumour models using three different methods. In this study, we attempted to elucidate the roles of the pia mater in brain metastasis. The metastatic foci showed an angiocentric pattern, forming collars of neoplastic cells, and were designated 'perivascular proliferations'. Furthermore, we observed neoplastic cells that infiltrated the brain parenchyma, the border of which had become indistinct. These were labelled 'invasive proliferations'. The internal carotid artery injection model reflects haematogenous metastasis. In this model, both perivascular and invasive proliferations were observed. The intrathecal injection model reflects leptomeningeal carcinomatosis. In this model, metastasis to the meninges was observed. In the stereotactic injection model, the tumour proliferation at the injection site and the infiltration into the brain parenchyma were observed. The pia-glial membrane serves as a scaffold when neoplastic cells spread to the perivascular space forming angiocentric pattern. The pia-glial membrane is found between the brain parenchyma and blood vessels. Blood vessels penetrate the brain through tunnels known as perivascular spaces that are covered by pia mater. Three different methods which we prepared reflect three different pathological processes. Our findings suggest that the pia mater is a critical factor in brain metastasis.     

A comparative ultrastructural study of chondrosarcoma, chordoid sarcoma, chordoma and chordoma periphericum

The present study is based on electron microscopical examinations of 15 conventional chondrosarcomas, 1 clear cell chondrosarcoma, 3 mesenchymal chondrosarcomas, 2 so-called chordoid sarcomas (extraskeletal myxoid chondrosarcoma), 4 sacrococcygeal chordomas, 2 ecchordoses and 1 neoplasm of tibia with features of a true peripheral chordoma (parachordoma). The neoplastic cells from various types of chondrosarcoma shared a number of features with nonneoplastic chondrocytes as e.g. a well-developed rough endoplasmic reticulum and microvillous cytoplasmic processes. In clear-cell chondrosarcoma, glycogen accumulation in the tumour cells was a prominent feature. The cells of mesenchymal chondrosarcoma usually showed the characteristics of immature mesenchymal cells. In contrast, chordomas commonly contained physaliferous cells with two types of vacuoles in their cytoplasm. The first type can be most adequately characterized as intracytoplasmic pseudoinclusions of intercellular substance, whereas the other type, glycogen-containing, single membrane-bound vacuoles most probably correspond to autophagosomes (cytolysosomes). Only vacuoles of the first type were recorded in the so-called chordoid sarcoma. They were also seen in chondrosarcomas. In contrast, both types of vacuoles were identified in the above-mentioned tibial tumour which, in addition, showed even other cytological characteristics of chordoma. The findings presented here have demonstrated distinct structural relationships between chordoid sarcoma and chondrogenic tumours. On the other hand, our observation of the uncommon tibial neoplasm indicates the possibility that tumours identical with chordoma may occur at sites other than the axial skeleton.     

Noninvasive sacral chordoma presenting as a benign soft tissue mass

In this case report, we describe a sacral chordoma, which had an atypical presentation as a mobile, encapsulated, benign soft tissue mass. The patient was asymptomatic, except for the slight enlargement of this lesion. Biopsy of this mass showed a lobulated tumor with bland neoplastic cells in a rich myxoid matrix with the classical immunohistochemical profile of chordoma. Opposite to this classical histological picture of chordoma, the imaging studies (computed tomography and magnetic resonance imaging) could not find any sacral involvement or lytic destruction. Surgical excision of this chordoma confirmed all preoperative findings and diagnoses, showing an encapsulated mass in the sacral soft tissue that has not invaded into the sacrum. This chordoma originated from the sacrococcygeal joint and grew parallel to the sacrum and below the skin. At the same time, histological sections and immunostains reconfirmed diagnosis of chordoma.     

Cystic papillary meningioma with subarachnoid dissemination: A case report and review of the literature

Meningiomas usually present as benign tumors corresponding to WHO grade I. The development of the papillary variant of meningiomas with cyst formation in the central nervous system is extremely rare. We report a case of cystic papillary meningioma in a young female occurring in the lateral ventricle with invasion of brain parenchyma and dissemination of subarachnoid space. The tumor exhibits a marked peritumoral cyst, with contrast enhancement on magnetic resonance imaging (MRI) in accordance with type 2 of Zee's classification of cystic meningioma. Histologically, the tumor displays a classical perivascular pseudopapillary pattern with focal necrosis and subarachnoid space dissemination. Tumor cells are diffusely positive for epithelial membrane antigen (EMA) and vimentin, but lack immunoreactivity for cytokeratin (CK) and glial fibrillary acidic protein (GFAP). MIB-1 labeling is high, accounting for 5% of tumor focally. A diagnosis of primary intraventricular cystic papillary meningioma with subarachnoid space dissemination (WHO grade III) was made. To our knowledge, there is no report describing the radiological and histological characteristics of cystic papillary meningioma presenting in the lateral ventricle. In addition, the biological behavior and the clinical outcome of this tumor are also discussed.