Pathogenesis and diagnostic pitfalls of ventricular diverticula: case report and review of the literature

OBJECTIVE AND IMPORTANCE: Ventricular diverticula are local herniations of the ventricular system occurring in association with severe, long-standing hydrocephalus. Variability in the extent and location of these ventricular pouches may produce misleading radiological conformations and raise diagnostic challenges. In this report, we discuss the pathogenesis and differential diagnosis of ventricular diverticula on the basis of a case illustration. CLINICAL PRESENTATION: We report the case of a 38-year-old woman presenting with hydrocephalus secondary to an obstructive lesion of the third ventricle. A large, dilated structure compressing the brainstem was present in the posterior fossa. INTERVENTION: The posterior fossa lesion was identified as an atrial diverticulum by injection of contrast medium into the right lateral ventricle, which led to immediate enhancement of the infratentorial cavity. Ventricular drainage and removal of the third ventricular lesion, a colloid cyst, allowed progressive collapse of the diverticulum and symptom resolution. CONCLUSION: This report discusses the pathogenesis of ventricular diverticula and demonstrates that ventriculography can be used to differentiate atrial diverticula from other posterior fossa lesions when time-consuming multiplanar magnetic resonance imaging cannot be afforded on an emergency basis.     

经小脑延髓裂入路显微手术切除儿童第四脑室肿瘤

目的 报道经小脑延髓裂入路显微外科手术切除儿童第四脑室肿瘤的临床疗效。方法 采用枕下正中切口、小脑延髓裂入路在手术显微镜下切除第四脑室肿瘤18例。结果 手术治疗18例，其中肿瘤全切除13例，近全切除5例。术后无l例出现小脑性缄默综合征。出现脑积水3例，2例经行侧脑室．腹腔分流后好转，l例因急性梗阻性脑积水死亡。结论 经小脑延髓裂入路，不需切开小脑蚓部，可避免损伤正常小脑组织，应用显微外科技术有助切除第四脑室肿瘤，提高手术疗效。     

Fourth ventricle central neurocytoma: case report

OBJECTIVE AND IMPORTANCE: Central neurocytomas (CNs) are typically located in the lateral ventricle. Primary origins in the fourth ventricle are very rare. We discuss the clinical symptoms, imaging findings, and microscopic features of these rare tumors. CLINICAL PRESENTATION: We report a case of a fourth ventricle CN in a 35-year-old male patient with the initial symptoms of progressive headaches and blurred vision for more than 2 months. Computed tomography and magnetic resonance imaging of the brain revealed a slightly enhanced tumor in the fourth ventricle, with obstructive hydrocephalus. INTERVENTION: Total surgical removal of the tumor was performed. The tumor was initially diagnosed as an oligodendroglioma. The final definitive diagnosis as a CN was made after special immunohistochemical studies. CONCLUSION: CNs located in the fourth ventricle are extremely rare. Immunohistochemical stains and transmission electron microscopy can provide useful diagnostic information. Total tumor excision is associated with favorable prognoses. Postoperative radiotherapy may be considered for cases of subtotal excision, anaplastic histological variants, or recurrent tumors.     

Acute obstructive hydrocephalus associated with infratentorial subdural hygromas complicating Chiari malformation Type I decompression. Report of two cases and literature review

Obstructive hydrocephalus complicating foramen magnum decompression (FMD) for a Chiari malformation (CM) Type I is rare. Two female patients (17 and 55 years old) presented with strain-related headaches. In both cases magnetic resonance (MR) imaging studies confirmed a CM Type I, which was accompanied by syringomyelia in one case. Both patients underwent uncomplicated FMD with good initial recovery. Unfortunately, conditions in both patients deteriorated, with severe headaches occurring between Days 5 and 6 post-FMD. Decreased consciousness occurred in one case. In both patients, computerized tomography scanning demonstrated an acute obstructive hydrocephalus associated with bilateral infratentorial extraaxial fluid collections (EAFCs). In addition, left parafalcine and convexity EAFCs were present in one case. An emergency external ventricular drain was required in one patient, with delayed conversion to a ventriculo-peritoneal shunt. Spontaneous resolution occurred in the other patient without neurosurgical intervention. In both cases, MR imaging confirmed that each EAFC was subdural, resembled cerebrospinal fluid (CSF), and had distorted the superior cerebellum anteroinferiorly. Despite upper fourth ventricle/aqueduct compromise in one case, normal aqueduct flow artifacts were apparent on examination. All EAFCs resolved spontaneously. Obstructive hydrocephalus complicating FMD is rare but invariably associated with infratentorial EAFCs, which were confirmed to be subdural hygromas in this report. The authors assert that hydrocephalus results from upper fourth ventricle/aqueduct compromise as a result of CSF subdural dissection following a pinhole arachnoid tear on durotomy. Because such hygromas spontaneously resolve, permanent shunt insertion should be avoided.     

A case of quadrigeminal cistern arachnoid cyst associated with hydrocephalus

A case of quadrigeminal cistern arachnoid cyst associated with hydrocephalus is reported. A 1-year-old girl was admitted to our service on July 31, 1984, because of mental retardation and an enlarged head. She was born of a full-term pregnancy and normal vaginal delivery without prenatal complications. Progressive increase in her head circumference was noticed at the age of 6 months by her family physician. On admission she was found to be a well-nourished infant with a head circumference of 56 cm, bulging anterior fontanelle and mental retardation. Marked dilatation of the lateral ventricles and a large cyst in the quadrigeminal cistern were demonstrated on plain CT. There were no findings of communication between the ventricular system and the cyst on metrizamide CT ventriculography. The extension of the cyst from the quadrigeminal cistern to the right cerebello-pontine angle was demonstrated on reconstructed coronal CT. Reconstructed sagittal section revealed huge hydrocephalus caused by aqueductal stenosis. A vertebral angiography demonstrated opening of the para-mesencephalic segments of the bilateral posterior cerebral arteries and downward displacement of the right superior cerebellar artery. Accordingly, a large quadrigeminal cistern arachnoid cyst with hydrocephalus caused by aqueductal stenosis was suspected. Following V-P shunt operation for hydrocephalus, right temporo-parietal craniotomy was performed. The inner wall of the lateral ventricle was thin and an expanding cyst was observed through it. A partial resection of the cyst wall with the ventricular wall was performed to obtain communication between the cyst and lateral ventricle. The content of the cyst was watery clear fluid like CSF.(ABSTRACT TRUNCATED AT 250 WORDS)     

Microsurgical anatomy of the choroidal fissure

The microsurgical anatomy of the choroidal fissure was examined in 25 cadaveric heads. The choroidal fissure, the site of attachment of the choroid plexus in the lateral ventricle, is located between the fornix and thalamus in the medial part of the lateral ventricle. The choroidal fissure is divided into three parts: (a) a body portion situated in the body of the lateral ventricle between the body of the fornix and the thalamus, (b) an atrial part located in the atrium of the lateral ventricle between the crus of the fornix and the pulvinar, and (c) a temporal part situated in the temporal horn between the fimbria of the fornix and the lower surface of the thalamus. The three parts of the fissure are the thinnest sites in the wall of the lateral ventricle bordering the basal cisterns and the roof of the third ventricle. Opening through the body portion of the choroidal fissure from the lateral ventricle exposes the velum interpositum and third ventricle. Opening through the temporal portion of the choroidal fissure from the temporal horn exposes the structures in the ambient and crural cisterns. Opening through the atrial portion of the fissure from the atrium exposes the quadrigeminal cistern, the pineal region, and the posterior portion of the ambient cistern. The neural, arterial, and venous relationships of each part of the fissure are reviewed. The operative approaches directed through each part of the fissure are also reviewed.     

Case of spontaneous ventriculocisternostomy: with special reference to a CT finding

Spontaneous ventriculocisternostomy rarely occurs in obstructive hydrocephalus. The authors experienced a case of spontaneous ventriculocisternostomy diagnosed by CT scan with metrizamide and Conray. Patient was 23-year-old male who had been in good health until one month before admission, when he began to have headache and tinnitus. He noticed bilateral visual acuity was decreased about one week before admission and vomiting appeared two days before admission. He was admitted to our hospital because of bilateral papilledema and remarkable hydrocephalus diagnosed by CT scan. On admission, no abnormal neurological signs except for bilateral papilledema were noted. Immediately, right ventricular drainage was performed. Pressure of the ventricle was over 300 mmH2O and CSF was clear. PVG and PEG disclosed an another cavity behind the third ventricle, which was communicated with the third ventricle, and occlusion of aqueduct of Sylvius. Metrizamide CT scan and Conray CT scan showed a communication between this cavity and quadrigeminal and supracerebellar cisterns. On these neuroradiological findings, the diagnosis of obstructive hydrocephalus due to benign aqueduct stenosis accompanied with spontaneous ventriculocisternostomy was obtained. Spontaneous ventriculocisternostomy was noticed to produce arrest of hydrocephalus, but with our case, spontaneous regression of such symptoms did not appeared. In the literature, arrest of hydrocephalus was noted in 50 per cent of 14 cases of obstructive hydrocephalus with spontaneous ventriculocisternostomy. By surgical ventriculocisternostomy (method by Torkildsen, Dandy, or Scarff), arrest of hydrocephalus was seen in about 50 to 70 per cent, which was the same results as those of spontaneous ventriculocisternostomy. It is concluded that VP shunt or VA shunt is thought to be better treatment of obstructive hydrocephalus than the various kinds of surgical ventriculocisternostomy.     

Selection of surgical approach for quadrigeminal cistern arachnoid cyst

Preoperative magnetic resonance imaging of 4 cases of quadrigeminal cistern arachnoid cyst were retrospectively reviewed and patterns of extension to surrounding cisterns from the quadrigeminal cistern were examined. Relationship between patterns of extension to surrounding cisterns and selected surgical approach were evaluated. In 2 cases, the cyst extended anteriorly and compressed the quadrigeminal plate. These two cases had hydrocephalus due to aqueductal stenosis. The anteroirly extending cyst was treated with endoscopic ventriculocystocisternostomy via the lateral and third ventricles. In one case, the cyst extended superiorly to the velum interpositum cistern, and was treated with endoscopic ventriculocystocisternostomy via the lateral ventricle. In one case, the cyst extended laterally to the ambient cistern and compressed the posterior horn of the lateral ventricle. This case had loculated hydrocephalus of the inferior horn. The laterally extending cyst was treated with resection of the wall of the arachnoid cyst via an infratentorial supracerebellar approach assisted by endoscope. All cysts were successfully treated. Injury of the foramen of Monro occurred during a procedure using a flexible endoscope in a case with an anterior extending cyst. Exact analysis of the preoperative imaging and selection of appropriate surgical approach are key factors for successful treatment of a quadrigeminal cistern arachnoid cyst.     

Pineoblastoma showing unusual ventricular extension in a young adult--case report.

A 19-year-old male presented with a 4-week history of headache. Neurological examination showed bilateral papilledema. Computed tomography revealed a pineal region mass with remarkable obstructive hydrocephalus. Magnetic resonance imaging showed a pineal region tumor continuously invading through the tectum into the cerebral aqueduct and the fourth ventricle with the preservation of the adjacent structures. The tumor appeared an iso- to hypointense mass on T1-weighted images, a heterogeneous iso- to hyperintense mass on T2-weighted images, and a heterogeneously enhanced mass after administration of contrast medium. Histological examination after endoscopic biopsy confirmed that the tumor was a pineoblastoma. Radiotherapy was given to the whole brain and the spinal cord, and magnetic resonance imaging showed complete remission of the tumor. Pineoblastomas are highly malignant tumors with seeding potential through the neighboring ventricle or along the meninges, and this type of tumor becomes larger with local extension. We found no previous reports of the continuous extension into the fourth ventricle. The present case showed ventricular extension with minimal mass effect to adjacent structures, and did not disturb ventricular configuration. According to the unusual finding of ventricular extension, this rare case of pineoblastoma requires adjuvant chemotherapy.     

Analysis of single-staged resection of a fourth ventricular tumor via a combined infratentorial-supracerebellar and telovelar approach: Case report and review of the literature

INTRODUCTIONThe authors explore a combined infratentorial-supracerebellar and telovelar approach in an adult, while avoiding vermian-splitting methods for a large, midline, fourth-ventricular tumor, unapproachable though a single traditional route. Experience with a combined surgical approach for pediatric patients has been published, but the authors believe that describing this combined method in an adult will provide a preliminary experience for further exploration of this approach in other adult patients.PRESENTATION OF CASEThe authors present a review of the literature along with the case of a 60-year-old man with slight ataxia who presented with a 1-month history of gait difficulty and memory lapse. His MRI of the brain showed mild hydrocephalus and a large tumor of the fourth ventricle. Surgical removal through a suboccipital craniotomy was attempted, and part of the tumor overlying the tectum and the superior cerebellar velum was removed without difficulty. However, despite inferior retraction of the vermis, which allowed further resection of the tumor from the fourth ventricle, residual tumor in the caudal surgical resection cavity was present. Partial transection of the vermis was considered, but avoided because of potential neurological deficits. Instead, the authors redirected their approach and exposed the residual tumor by transecting the inferior medullary velum and removed additional tumor while avoiding the floor of the fourth ventricle. The infratentorial-supracerebellar and telovelar approach resulted in total gross resection of the tumor.DISCUSSIONFor patients with large midline tumors that arise from the superior vermis or the quadrigeminal plate and fill the upper third of the fourth ventricular space, this combined approach may offer a unique possibility of safe tumor removal.CONCLUSIONThis case demonstrates the benefit of a combined approach for a select group of patients.     

Hydrocephalus due to idiopathic stenosis of the foramina of Magendie and Luschka. Report of three cases

Idiopathic stenosis of the foramina of Magendie and Luschka is a rare cause of obstructive hydrocephalus involving the four ventricles. Like other causes of noncommunicating hydrocephalus, it can be treated with endoscopic third ventriculostomy (ETV). Three patients who were 21, 53, and 68 years of age presented with either headaches (isolated or associated with raised intracranial pressure) or vertigo, or a combination of gait disorders, sphincter disorders, and disorders of higher functions. In each case, magnetic resonance (MR) imaging demonstrated hydrocephalus involving the four ventricles (mean transverse diameter of third ventricle 14.15 mm; mean sagittal diameter of fourth ventricle 23.13 mm; and mean ventricular volume 123.92 ml) with no signs of a Chiari Type I malformation (normal posterior fossa dimensions, no herniation of cerebellar tonsils). The diagnosis of obstruction was confirmed using ventriculography (in two patients) and/or MR flow images (in two patients). All patients presented with marked dilation of the foramen of Luschka that herniated into the cisterna pontis. All patients were treated using ETV. No complications were observed. All three patients became asymptomatic during the weeks following the surgical procedure and remained stable at a mean follow-up interval of 36 months. Postoperative MR images demonstrated regression of the hydrocephalus (mean transverse diameter of third ventricle 7.01 mm; mean sagittal diameter of fourth ventricle 16.6 mm; and mean ventricular volume 79.95 ml), resolution of dilation of the foramen of Luschka, and good patency of the ventriculostomy (flow sequences). These results confirm the existence of hydrocephalus caused by idiopathic fourth ventricle outflow obstruction without an associated Chiari Type I malformation, and the efficacy of ETV for this rare indication.     

Third ventricular glioblastoma multiforme: Case report

Intraventricular neoplasms of the third ventricle represent a small minority of intracranial tumors. Furthermore, few cases of solitary, third ventricular glioblastoma multiforme were reported in the literature. The authors report a case of a fifty-nine year olf man who presented with progressive gait disturbance, disorientation, diffuse headache, and vomiting. Computed tomography and magnetic resonance imaging (MRI) confirmed a solitary third ventricular ringenhancing lesion and obstructive hydrocephalus. The final pathology of the lesion upon permanent section was glioblastoma multiforme (GBM). The clinical course, radiologic findings, the possible origin of this lesion, as well as possible treatment regimen are discussed.     

Endoscopic ventriculocystocisternostomy of a quadrigeminal cistern arachnoid cyst. Case report.

The authors present the case of an elderly patient with a quadrigeminal arachnoid cyst who was successfully treated with endoscopic fenestration through the posterior wall of the third ventricle via the anterior horn of the lateral ventricle. This 71-year-old man suffered from progressive gait instability and disorientation. Radiological examination revealed hydrocephalus caused by a quadrigeminal arachnoid cyst. The patient underwent endoscopic fenestration of the quadrigeminal cistern arachnoid cyst and third ventriculostomy via one burr hole placed at the coronal suture. This method is less invasive and is effective for quadrigeminal cistern arachnoid cyst and accompanying hydrocephalus.     

Experimental transcerebral fistula. Perineural olfactory CSF flow in the normal, hydrocephalic, and postoperative hydrocephalic dog shown by radionuclide ventriculography

Cerebrospinal fluid dynamics were studied in eight dogs during normal, hydrocephalic, and postoperative phases. Radionuclide-labeled substances introduced into the normal ventricular system flow out of the exits from the fourth ventricle to the convexity subarachnoid spaces superiorly to be absorbed in the sagittal sinus, and basorostrally to the exits from the perineural olfactory sheath into the nose to produce physiological cerebrospinal fluid (CSF) rhinorrhea. Serial radionuclide ventriculography of the head following intraventricular isotope injection of labeled proteins and chelate into the kaolin-induced hydrocephalic system shows a high degree of ventricular stasis with no perineural olfactory nerve flow (rhinorrhea). An operative transcerebral fistula, fashioned from a dilated lateral ventricle to the convexity subarachnoid space, reestablishes perineural olfactory flow of CSF into the nose, as demonstrated by the radionuclide ventriculography studies. This suggests a potential method for treatment of hydrocephalus. Serial imaging studies in this surgically modified system clearly demonstrate radionuclide flow through the patent fistula to distal absorption sites, thereby bypassing the basal obstruction. Moreover, augmented CSF pressures associated with obstructive hydrocephalus can be controlled by such treatment. The application of this method in treating clinical hydrocephalus is discussed with emphasis on fistula arachnoid closure to assure fistula patency.     

Clinical, histological, and genetic features of fourth ventricle ependymoma in the elderly

A 71-year-old woman presented with a rare case of geriatric ependymoma originating from the fourth ventricle manifesting as progressive gait and memory disturbance. Imaging studies revealed an extraaxial mass in the fourth ventricle protruding into the right cerebellomedullary cistern, with concomitant obstructive hydrocephalus. Surgery achieved subtotal removal since the tumor tightly adhered to the right vestibular area of the fourth ventricular floor. The histological diagnosis was ependymoma, which was also confirmed by comparative genetic hybridization. Although she developed severe laryngeal edema and worsening of the hydrocephalus postoperatively which required additional treatment, she recovered with residual mild gait disturbance, and was transferred to a rehabilitation facility. Fourth ventricle ependymoma in the elderly is rare. Comparative genetic hybridization may be important in the diagnosis of geriatric ependymoma and in the choice for adjuvant therapy as well as in estimating the prognosis for patients with rare types of ependymoma.     

Syringomyelia with obstructive hydrocephalus at the foramens of Luschka and Magendie successfully treated by endoscopic third ventriculostomy

BACKGROUND: Syringomyelia rarely accompanies hydrocephalus except for the cases with Chiari malformation, and the efficacy of endoscopic third ventriculostomy for this entity is undetermined. CASE REPORT: A 55-year-old man developed sensory disturbance and discrete movement disturbance on the bilateral upper limb during the past 3 years. On admission, he presented with slight tetraparesis and hyperreflection on his lower limbs with rectovesical dysfunction. Preoperative MR imaging demonstrated marked enlargement of the lateral ventricles as well as the third and fourth ventricle due to obstruction of the foramens of Luschka and Magendie. Spine MR imaging showed longitudinal dilatation of the central canal from the cerebrospinal junction toward the thoracic level with communication to the fourth ventricle, whereas Chiari malformation and tight cisterna magna were absent. He was successfully treated by ETV. The patient significantly recovered from his symptoms postoperatively, and MR imaging after surgery showed apparent shrinkage of the syrinx as well as the ventricles. CONCLUSION: The efficacy of the normalization of cerebrospinal fluid circulation and subsequent improvement of the syringomyelia in the present case may suggest that ETV could be a therapeutic choice for syringomyelia associated with hydrocephalus due to the obstruction of the foramens of Luschka and Magendie, especially when the connection between the ventricular system and the dilated central canal is evident, and may give a clue to the explanation for Gardner's hydrodynamic theory.     

Successful neuroendoscopic third ventriculostomy for hydrocephalus and syringomyelia associated with fourth ventricle outlet obstruction. Case report

The authors report the use of neuroendoscopic third ventriculostomy to treat successfully both hydrocephalus and syringomyelia associated with fourth ventricle outlet obstruction. A 27-year-old woman presented with dizziness, headache, and nausea. Magnetic resonance (MR) imaging demonstrated dilation of all ventricles, downward displacement of the third ventricular floor, obliteration of the retrocerebellar cerebrospinal fluid (CSF) space, funnellike enlargement of the entrance of the central canal in the fourth ventricle, and syringomyelia involving mainly the cervical spinal cord. Cine-MR imaging indicated patency of the aqueduct and an absent CSF flow signal in the area of the cistema magna, which indicated obstruction of the outlets of the fourth ventricle. Although results of radioisotope cisternography indicated failure of CSF absorption, neuroendoscopic third ventriculostomy completely resolved all symptoms as well as the ventricular and spinal cord abnormalities evident on MR images. Neuroendoscopic third ventriculostomy is an important option for treating hydrocephalus in patients with fourth ventricle outlet obstruction.     

Isolated ventricles following intraventricular hemorrhage

Panventricular enlargement often follows intraventricular hemorrhage in the premature neonate. During a recent 12-month period, the authors identified five infants who required shunting because of symptomatic post-hemorrhagic hydrocephalus, which was progressive despite serial lumbar punctures and the use of indwelling subcutaneous ventricular reservoirs. In the first 6 months following placement of the initial shunt, four of the infants required an additional shunt for isolated ventricles. Two children had isolation of the lateral ventricles and required bilateral shunts. Two other children had isolation of the fourth ventricle from the lateral ventricular system and required posterior fossa shunts. All of the children were treated successfully using multiple shunts. In all cases, progressive dilation of the isolated ventricle was unaccompanied by the usual clinical signs of shunt malfunction. It appears that isolated ventricular systems are common following post-hemorrhagic hydrocephalus and these children must be followed closely with ultrasound and computerized tomography scanning.     

Epidermoid cysts of the fourth ventricle

The location of epidermoid cysts within the fourth ventricle is rare. The Authors present three cases operated on. The most frequent symptom was ataxia. Increased intracranial pressure and hydrocephalus were rare even when the tumors were large in size and filled up the fourth ventricle. Neuroradiological data are presented. Surgical removal was generally easy though the tumor invaded the cisterns and a true peritumoral capsule was found only in the lower part of the ventricular floor. The bursting of the cyst followed by continuous production of keratin with subsequent invasion of cisterns and foramina is suggested as a possible mechanism to explain the tumoral growing.     

Isolated fourth ventricle as a complication of ventricular shunting. Report of three cases.

Signs of cerebellar dysfunction combined with signs suggestive of shunt malfunction developed in three children with obstructive hydrocephalus. Shunt function was normal. In all cases, the cerebellar signs persisted and computerized tomography scans revealed enlargement of the fourth ventricle. Shunting of the fourth ventricle returned the patients to normal function.