Symptomatic infratentorial ependymal cyst arising from the medulla: a case report with review of literature.

BACKGROUND: Ependymal cysts (EC) typically present supra-tentorially near the lateral ventricle, juxta ventricular, or temporoparietal regions. Previous cases have also identified infratentorial EC of the brainstem, cerebellum, and subarachnoid spaces. They are mostly asymptomatic. In this paper, we present the first-ever case of a symptomatic medullary ependymal cyst treated with surgery, along with a comprehensive review of the literature on EC of other parts of the brain stem. CASE DESCRIPTION: This 51-year-old female presented with hearing loss, dizziness, diplopia, and ataxia. Radiographic imaging indicated the presence of a non-enhancing lesion in the medulla with a mass effect on the brainstem. Pathological examination confirmed its characterization as an ependymal cyst. The patient underwent a suboccipital craniotomy for the fenestration of the medullary ependymal cyst under neuro-navigation, Intra-op ultrasound and intra-operative neuro-monitoring. Histopathological examination confirmed the diagnosis of an ependymal cyst. At one month follow-up, her KPS is 90, ECOG PS 1, and her ataxia has improved with complete resolution of diplopia. CONCLUSION: Due to their rarity and potential similarity to other cystic structures, EC may be overlooked or incorrectly diagnosed resulting in mismanagement and surgical disaster. Therefore, a comprehensive understanding and awareness of their distinct characteristics are essential for accurate diagnosis and appropriate management.

Intracranial ependymal cyst - A modern systematic review with a pathway to diagnosis.

BACKGROUND: Intracranial ependymal cysts (IECs) are rare, histologically benign neuroepithelial cysts that mostly occur in the cerebral parenchyma. The majority of these cysts are clinically silent and discovered incidentally, but when symptomatic they may compress surrounding structures, thus surgical intervention is needed. The current data in the literature about ECs is very scarce, and many are misdiagnosed, once they share many radiological characteristics with a variety of intracranial benign cysts. Also their terminology is confusing, and its definitive diagnosis can only be made through a thorough histopathological study, hence a detailed description about these uncommon lesions is necessary. The correct identification of the lesion lead to our better understanding of the condition and further improvement of the patient's prognosis. METHODS: A descriptive case is presented; moreover, a detailed PubMed search according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline was performed. The data found was analyzed by various criteria in order to correctly describe the characteristics of this lesion. RESULTS: The literature review gathered 9 descriptions of patients with IECs with a diverse range anatomopathological and clinical manifestations. All of the included studies found were case reports. Moreover, the authors suggest an updated classification of the lesion, involving their immunohistochemical characteristics. CONCLUSIONS: The information obtained from this study highlights IECs rarity and their inaccurately classification. We propose that the definitive diagnosis of IECs shall be made upon histopathological confirmation of an ependyma-lined cyst along with a positive glial fibrillary acidic protein (GFAP).

A Rare Case Report of Encephalocele with Numerous Ependymal Components: A Potential Diagnostic Pitfall.

Different cellular constituents of the central nervous system occurring in encephaloceles or neuroglial heterotopias (NGHs) have been reported, but the ependymal morphology has rarely been described in the previous literature, let alone the related histological images. To determine the ependymal morphology in encephaloceles or NGHs, we report a rare case of encephalocele with numerous ependymal components. Radiological examination showed that a 6.2 × 3.1 cm nasal dorsum mass-forming encephalocele in a 24-year-old woman, who had an intracranial connection through a frontal bone defect. This patient underwent a resection of the encephalocele under nasal endoscopy and a reconstruction of the cranial base. The patient had a good prognosis with no postoperative complications during follow-up. Microscopically, the ependymal components entrapped in a collagenized background showed numerous slit-like spaces lined by columnar cells with abundant palely eosinophilic cytoplasm and apical surface microvilli. With immunohistochemistry, in addition to the expression of EMA along with the slit-like spaces, GFAP and S100 were diffusely expressed in the slit-like spaces. In conclusion, the ependymal component in either encephaloceles or NGHs may present slit-like spaces arranged in an anastomosing pattern. The unusual morphology of ependyma continues to be underrecognized by pathologists and is easily misdiagnosed; therefore, an awareness of the morphological change in ependyma is necessary.

Ependymal fluorescence in fluorescence-guided resection of malignant glioma: a systematic review.

BACKGROUND: Fluorescence in the ventricular wall or the ependyma during fluorescence-guided resection (FGR) of malignant glioma is commonly observed when malignant gliomas infiltrate the ventricles. However, the underlying pathophysiology and clinical importance are largely unknown but may play a role in deciding whether to continue resection into the ventricles or not. Here, we systematically review available data regarding ependymal fluorescence in FGR using five aminolevulinic acid (5-ALA) and sodium fluorescein (SF). METHODS: A literature search on MEDLINE, EMBASE, and WEB OF SCIENCE was performed using the following headings and search operators: ependy* fluorescence AND (5-ALA OR five aminolevulinic acid), ventric* wall fluorescence AND (5-ALA OR five aminolevulinic acid), ependy* fluorescence AND fluorescein, and ventric* wall fluorescence AND fluorescein. Both authors analyzed abstracts independently. Included articles were further reviewed for prevalence of ependymal fluorescence, patterns of fluorescence, and histopathological characteristics of sampled tissues as well as radiological signs of ependymal fluorescence. Results are reported according to the PRISMA statement. RESULTS: Of 202 records identified, 6 studies were included compiling a total number of 198 patients treated with FGR using 5-ALA. No study on ependymal fluorescence after administration of SF was found. Overall prevalence of ependymal fluorescence was 61.4%. A total of 54.5% of cases were found to be positive for tumor cells. A total of 25.5% of patients with ependymal fluorescence were related to contrast enhancement in ventricular walls. CONCLUSIONS: The phenomenon of ventricular wall fluorescence in 5-ALA-derived fluorescence-guided resection of malignant glioma is poorly understood and not always may fluorescence represent tumor infiltration. A larger scale prospective sampling study with molecular analyses is currently ongoing and will hopefully provide further insight into pathophysiology and clinical implications of ependymal fluorescence.

Endoscopic treatment of intraventricular ependymal cysts in children: personal experience and review of literature.

OBJECT: Intracranial ependymal cysts are rare neuroepithelial cysts that occur less frequently than arachnoid cysts. The cysts are most often intraparenchymal, but they are rarely reported to be intraventricular. This study evaluates the role of endoscopy in the treatment of intraventricular ependymal cysts (IVECs). METHODS: Twelve pediatric patients (mean age 4.3 years) with symptomatic IVECs were the subject of this study. The cyst was located inside the lateral ventricle in all cases (100%), it was present in trigone (10 patients, 83.3%), and in temporal horn (2 patients, 16.7%). Concomitant hydrocephalus was present in two patients (16.7%). All patients underwent operations through a purely endoscopic procedure. Communication of the cyst with the subarachnoid space was performed in six patients (50%); endoscopic cystocisternostomy was performed in four patients (33.3%), and endoscopic cystoventriculostomy in two patients (16.7%). RESULTS: Postoperative clinical improvement associated with postoperative reduction in cyst size was encountered in ten patients (83.3%). Improvement of hydrocephalus occurred in both patients who had hydrocephalus (100%). There were no deaths or permanent morbidity. Among the follow-up period (mean 44.3 months), none of the patients required a repeat endoscopic procedure due to recurrence of symptoms or increase in cyst size. CONCLUSION: Intraventricular ependymal cysts can be effectively treated by endoscopy. Endoscopic fenestration of the cyst wall into subarachnoid space, basal cisterns, or ventricular system can be used in the treatment of these patients with postoperative symptomatic improvement and reduction of cyst size. The procedure is simple, effective, minimally invasive, and associated with low morbidity and mortality rates.

Discovery of Aquaporin-1 and Aquaporin-4 Expression in an Intramedullary Spinal Cord Ependymal Cyst: Case Report.

BACKGROUND: Intramedullary ependymal cysts of the spinal cord are rare, benign, fluid-filled cysts usually situated along the ventral surface of the spinal cord. Only 32 cases have been reported since they were first described. Thus, owing to the rarity at which these cysts are encountered, their management and pathogenesis remain controversial. Whereas some investigators have advocated for cystosubarachnoid shunt placement for symptomatic ependymal cysts, others have argued for complete cyst resection or simple fenestration. Here we report the case of a 56-year-old female with a T11-T12 ependymal cyst that was successfully managed with cyst fenestration. We further investigated a potential pathological mechanism of cyst formation by performing immunohistochemistry to detect aquaporin expression in the cyst lining. CASE DESCRIPTION: A 56-year-old female was found to harbor an enlarging cystic lesion of the conus that was discovered on workup of progressive paraparesis and urinary incontinence. She had lower extremity weakness and progressive myelopathy. Thoracic laminectomy with cyst fenestration arrested her neurologic deterioration. Pathological analysis revealed an intramedullary ependymal cyst. Immunohistochemistry was subsequently performed for expression of aquaporin-1 and aquaporin-4. There was dense staining of the underlying neuropil with concurrent membranous staining pattern of the cyst lining. CONCLUSIONS: Intramedullary ependymal cysts are rare, cystic lesions of the spinal cord. Early cyst fenestration decompresses the cyst and prevents neurologic deterioration. Here we report for the first time that aquaporins are expressed in the cyst wall, which is consistent with a passive, osmotic pathogenic mechanism of cyst formation.

Periventricular glioblastomas and ependymal involvement interrogated using intraoperative fluorescence - a pathological correlative study.

RATIONALE: Subventricular zone (SVZ) involvement has been proposed as an adverse prognostic factor in glioblastomas (GBM). The true extent of ventricular involvement at surgery is often difficult to establish and is poorly studied. Tumour fluorescence provides us with an exciting opportunity to interrogate tumour extent intraoperatively. METHODS: We conducted a retrospective analysis of all cases of GBMs operated using aminolevulinic acid-induced fluorescence and analyzed radiological SVZ involvement alongwith the incidence of ventricular entry at surgery, ependymal fluorescence and histological correlation of the ependymal involvement. RESULTS: Of 30 GBMs, radiological SVZ involvement was seen in 26 of which ventricles were opened at surgery in 19. Diffuse ependymal fluorescence was seen in 10 of the 19 cases (51%) and histology revealed tumour infiltration in only one of the five cases where ependymal tissue was sampled. Focal ependymal fluorescence seen in two of the 19 cases was always pathological. Diffuse ependymal fluorescence did not always correlate with gross appearance of the ventricular lining at surgery. Nor did it correlate with SVZ involvement. CONCLUSIONS: Pathological significance of diffusely fluorescing ependymal lining seen during surgery is questionable and need not represent tumour extension. Ependymal fluorescence may sometimes not be visualized even when the tumour appears to involve the SVZ. These results highlight the potential limitations of fluorescence especially in the bordering infiltrating zone where its predictive value is diminished.

Neuroendoscopic Approach to Intracranial Ependymal Cysts.

BACKGROUND: Intraparenchymal cysts without communication to the ventricles or the subarachnoid space are named ependymal or epithelial cysts. The estimated ratio of their incidence compared with arachnoid cysts is 1:10. Neurologic deficit can occur when the cyst exerts mass effect on its surroundings. We evaluated the success rate of endoscopic fenestration of intracranial ependymal cysts. METHODS: Our prospectively maintained endoscopy database was screened for all cases of ependymal cysts. The charts were retrospectively reviewed for symptoms, surgery, postoperative course, and complications. Magnetic resonance imaging scans performed before and after surgery were analyzed. RESULTS: We identified 6 patients harboring an intracranial ependymal cyst. The cyst location was frontoparietal, parietal, occipital, or mesencephalic. Patients presented with several symptoms according to the location of the cyst (i.e., epilepsy, hemiparesis, diplopia, hemianopsia). All patients were treated by navigation-guided endoscopic fenestration of the cyst to the ventricular system. Two complications occurred: a cerebrospinal fluid leak, which was managed surgically by wound revision without the need for cerebrospinal fluid shunting, and a chronic subdural hematoma, which occurred 6 weeks after surgery and required burr hole evacuation. Follow-up period ranged from 6 months to 9 years. Magnetic resonance imaging revealed that all cysts decreased in size. Symptoms improved in all patients. CONCLUSIONS: Endoscopic fenestration of ependymal cysts to an adjacent ventricular cavity is a treatment option with excellent long-term results and minimal morbidity. It should be considered as the therapy of choice to avoid craniotomy and shunt dependence.

Endoscope-Assisted Microsurgical Removal of an Intraventricular Ependymal Cyst That Manifested with Tremor.

BACKGROUND: Intraventricular ependymal cysts (ECs) are rare, histologically benign neuroepithelial cysts. Most of these cysts are clinically silent and discovered incidentally. Rarely, they become symptomatic, leading to obstruction of the cerebrospinal fluid circulation. ECs located inside the ventricles may manifest with signs of increased intracranial pressure. CASE DESCRIPTION: A 32-year-old woman presented with a 6-year history of tremor affecting her left hand. In the last month, she had been experiencing headache as well, and the tremor of the left hand was affecting her quality of life. The patient demonstrated a fine resting and intention tremor of the left hand and a voice tremor. Magnetic resonance imaging revealed a large cystic, nonenhancing lesion within the right lateral ventricle. The fluid within the cyst was isointense to cerebrospinal fluid on all sequences. Because of the rapid progression of her symptoms and no response to medication, surgical decompression of the cyst was considered. The cyst was removed by an endoscope-assisted microsurgical technique. Her postoperative course was uneventful. A marked reduction in her tremor was noted in the immediate postoperative period. Histopathologic diagnosis was of an EC. During the follow-up period, the patient's tremor, although still present, had improved dramatically. At 6 months postoperatively, she could hold a drinking glass without spilling. CONCLUSIONS: This is a unique case of an intraventricular EC that manifested with tremor, which improved by endoscope-assisted microsurgical removal of the cyst. This case also supports the important role of endoscopic surgery in the treatment of intraventricular cystic lesions.

Ependymal cell differentiation, from monociliated to multiciliated cells.

Primary and motile cilia differ in their structure, composition, and function. In the brain, primary cilia are immotile signalling organelles present on neural stem cells and neurons. Multiple motile cilia are found on the surface of ependymal cells in all brain ventricles, where they contribute to the flow of cerebrospinal fluid. During development, monociliated ependymal progenitor cells differentiate into multiciliated ependymal cells, thus providing a simple system for studying the transition between these two stages. In this chapter, we provide protocols for immunofluorescence staining of developing ependymal cells in vivo, on whole mounts of lateral ventricle walls, and in vitro, on cultured ependymal cells. We also provide a list of markers we currently use to stain both types of cilia, including proteins at the ciliary membrane and tubulin posttranslational modifications of the axoneme.

Development of a short sleeper phenotype after third ventriculostomy in a patient with ependymal cysts.

A naturally short sleeper phenotype with a sleep need of less than 6 hours without negative impact on health or performance is rare. We present a case of an acquired short sleeper phenotype after third ventriculostomy. A 59-year-old patient suffering from chronic hydrocephalus reported an average of 7-8 h of nocturnal sleep. After surgical intervention, the patient noted a strikingly reduced sleep need of 4-5 h without consequent fatigue or excessive daytime sleepiness, but with good daytime performance and well-balanced mood. Short sleep per 24 hours was confirmed by actigraphy. Postoperative imaging revealed decreased pressure around the anterior third ventricle. The temporal link between development of a short sleeper phenotype and third ventriculostomy is striking. This might suggest that individual short sleep need is not only determined by genetics but can be also be induced by external factors.

Spinal intramedullary ependymal cyst--current concepts for diagnosis and surgical management.

We describe a case of a 48-year-old woman who presented with neck pain and progressive left arm weakness. Magnetic Resonance Imaging showed a cervical intramedullary cystic lesion. The lesion was removed and neuropathological analysis revealed an ependymal cyst.

Infarction of the lateral posterior choroidal artery territory after manipulation of the choroid plexus at the atrium: causal association with subependymal artery injury.

OBJECT: The atrium of the lateral ventricle is often affected by tumors, and some patients with these tumors suffer neurological deficits, including hemiparesis after surgery. The authors of this study investigated the possible mechanisms causing the relatively high incidences of ischemic complications associated with surgery approaching the atrium of the lateral ventricle. METHODS: Clinical records and radiological images of 28 patients were retrospectively studied. These patients had their lateral ventricles opened at the atrium during the resection of gliomas as well as other nonbenign brain tumors, and were treated for gliomas at our tertiary referral center in the Tohoku district, Japan, between January 2008 and December 2010. RESULTS: Routine postoperative diffusion-weighted MR images obtained within 72 hours after surgery detected infarction in the periatrial/periventricular regions in 7 patients, presumably corresponding to the lateral posterior choroidal artery (LPChA) territory. Five of these 7 patients suffered neurological sequelae with varying severities. The choroid plexus at the atrium was coagulated to achieve hemostasis during the surgery in all of these patients. Detailed analysis of microangiograms revealed ventriculofugal arteries arising from the lateral ventricle. Damage of the subependymal artery that supplies the ventriculofugal arteries caused by coagulation of the choroid plexus at the atrium probably resulted in the infarction in these patients. CONCLUSIONS: Neurosurgeons must be aware of the possibility of LPChA territory infarction during surgery in the atrial or periatrial regions caused by subependymal artery obstruction after manipulating or coagulating the choroid plexus near the atrium.

Ependymal brain cyst with posterior cerebral artery infarct.

Primary intracranial ependymal cysts are congenital, benign, ependyma-lined cysts rarely seen in the pediatric age group. The authors report such a case of intracranial fronto-parietal ependymal cyst in a 3 y-old girl. Computed tomography showed a large cystic lesion which was not in communication with the ventricular system and was associated with ipsilateral posterior cerebral artery infarct and raised intracranial pressure causing midline shift. A differential diagnosis of the commoner arachnoid, hydatid or porencephalic cyst was considered. Surgical removal to decompress the brain was done; histopathology revealed an ependymal cyst. Identification of this rare pathology in the pediatric age group is emphasized with a review of the literature.

The inferior medullary velum: anatomical study and neurosurgical relevance.

OBJECT: Although it is often visualized surgically, details regarding the inferior medullary velum are lacking in the literature. The present study is intended to better elucidate this neuroanatomical structure using microsurgical and immunohistochemical analyses. METHODS: To study the inferior medullary velum, the authors performed microdissection in 15 adult cadavers. Following gross study, specimens were examined histologically. RESULTS: The inferior medullary velum extended from the flocculus to the middle cerebellar peduncle and stretched between the inferior cerebellar peduncle and the nodule and pyramid. The average thickness of the velum was found to be 0.5 mm (range 0.35-0.8 mm) and the average length was found to be 6 mm (range 5.5-7.2 mm). Arterial branches were identified in all specimens that arose from medullary branches of the posterior inferior cerebellar artery and supplied the inferior medullary velum. Histologically and from internal to external, a choroid plexus epithelium as a single cell layer was adjacent to a cuboidal layer of ependymal cells with no visible cilia. The next layer contained scattered glia in single cells or small clusters. The most external layer was composed of flat spindle cells resembling fibroblasts. No neurons of any type were identified. Only rare axons traversed the thin hypocellular zone that disappeared toward the midline. CONCLUSIONS: Based on this cadaveric study, the authors conclude that division of the inferior medullary velum should be relatively harmless as no neuronal cells were identified in this structure, which appears to be a vestigial bridge of tissue between the left and right sides of the cerebellum.

Ependymal cyst of the midbrain.

We present the case of a 30-year-old man who developed an acute hydrocephalus secondary to an obstruction of the cerebral aqueduct by a midbrain cystic lesion. After a ventriculo-peritoneal shunt was placed to relief symptoms of intracranial hypertension, the patient underwent a neuronavigation-assisted endoscopic fenestration of the cyst. A careful immunohistochemical staining confirmed the diagnosis of an ependymal cyst. An extensive review of the literature has revealed that this is the first report of a periaqueductal ependymal cyst with definite histological diagnosis. This is a rare cause of acute non-communicating hydrocephalus but an important entity in the differential diagnosis.

Intramedullary subependymoma of the cervical spinal cord: a case report with immunohistochemical study.

Spinal subependymomas, which have a relatively benign nature, are very rare tumors. It is difficult to distinguish spinal subependymomas from other intramedullary spinal tumors based on neuroradiological findings. A case of cervical intramedullary subependymoma in a 63-year-old female is reported. The diffused enlargement of the spinal cord at C2 level involved the lesion with isointensity on a T1-weighted MRI and relatively high intensity on a T2-weighted MRI. Enhancement in the small part of the tumor was observed on a T1-weighted MRI with gadolinium administration. The tumor occupied the left side of the spinal cord, and was totally removed through a laminoplasty of C2. Immunohistochemistry was useful for pathological diagnosis. The clinical feature of this patient is described with the review of literatures.

Endoscopic treatment of intraventricular cerebrospinal fluid cysts: 10 consecutive cases.

INTRODUCTION: The use of the endoscope for lesions of the central nervous system has been progressively widened in the past decades. Among these lesions, the intraventricular cyst is one of the most attractive targets for this less invasive procedure. METHODS: Between 2003 and 2007, ten consecutive patients with IVC underwent endoscopic surgery in our department. The location of the cyst was the lateral ventricle in nine, the lateral and third ventricles in one. The cyst was resected or fenestrated according to the degree of adhesion of the cyst wall with the ventricular wall. The follow-up ranged from 6 months to 54 months (mean: 22.5 months). RESULTS: The cyst was totally removed in three, subtotally removed in one, and fenestrated in six cases. Except for transient fever, there was no post-operative morbidity. During follow-up, all patients were doing well. CONCLUSION: The endoscopic technique is a good treatment option with the advantage of minimal invasiveness and less complications. The extension of the cyst and whether the hemisphere involved is dominant or not, determines the ideal endoscopic trajectory. The long-term efficacy of the endoscopic technique in treatment of IVC needs further evaluation.