Posterior Fossa Arachnoid Cyst Research Articles

Posterior Fossa Arachnoid Cyst Masking a Delayed Diagnosis of Hyperparathyroidism in a Child

Background. Primary hyperparathyroidism in childhood is a very rare entity, often being diagnosed late after the onset of its presenting symptoms. It most commonly affects patients in their fourth decade of life and beyond. The inclusion of primary hyperparathyroidism in the differential diagnosis is necessary when evaluating patients presenting with nonspecific symptoms such as polyuria, fatigue, weight loss, abdominal pain, nausea, and vomiting. Methods. We report the case of an eleven-year-old girl presenting with three years history of headaches, visual disturbance, along with episodes of emotional lability. Neuroimaging confirmed a large posterior fossa arachnoid cyst. It was decided to manage this lesion conservatively with surveillance. Only after further hospital admissions with recurrent loss of consciousness, dizziness, and nausea to add to her already existing symptoms, a full biochemical and endocrine assessment was performed to look for more specific causes for her presentation. These pointed to a diagnosis of primary hyperparathyroidism. Conclusions. The inclusion of primary hyperparathyroidism in the differential diagnosis should be considered when evaluating paediatric patients presenting with nonspecific (neurological, gastrointestinal, and renal) symptoms in order to establish a prompt diagnosis of the disorder and to avoid severe complications of prolonged hypercalcaemia and end-organ damage.

Large intradural craniospinal arachnoid cyst: A case report and review of literature

Presence of an arachnoid cyst at craniospinal junction is not very common. This is a very rare anatomic site, with only seven other cases reported in the literature. We report a case of large intradural craniospinal arachnoid cyst presenting with obstructive hydrocephalus and cranial nerve palsy. A 39-year-old male presented with 8-month history of neck pain, headache, vomiting, visual disturbances, diminished taste sensation, and numbness of face. He had bilateral papilledema on ophthalmoscopy. Magnetic resonance imaging (MRI) revealed a posterior fossa arachnoid cyst extending down to the lower border of C5 vertebra. Posterior decompression was done through C5 laminectomy. He made a full recovery and was asymptomatic at 6-month follow-up examination. The clinical features, diagnosis, and management of these rare craniospinal arachnoid cysts are discussed.

Acute respiratory failure after endoscopic third ventriculostomy: A case report and review of the literature

Endoscopic third ventriculostomy (ETV) is a relatively safe procedure. However, postoperative acute respiratory failure may be fatal. The authors report an 8-month-old patient with obstructive hydrocephalus secondary to posterior fossa cyst, and Chiari malformation. After ETV he developed difficulty in breathing, and had to be reintubated and ventilated. The infant recovered fully after craniocervical decompression and insertion of cystoperitoneal shunt. We speculate that respiratory failure is related to relative expansion of the posterior fossa arachnoid cyst, causing significant compression on the brain stem. Supportive care with mechanical ventilation and brain stem decompression were the mainstay of treatment.

Growing Posterior Fossa Arachnoid Cyst Causing Tonsillar Herniation and Hydrocephalus

A25-YEAR-OLDWOMAN without any significantmedicalortraumatichistorypresented with a 1-month episodeofrecurrentandprogressive bioccipitalheadachesandnausea.At age18years,shehadbeeninvestigated foroccasionalbitemporalheadachein alocalclinic,anda11-cmretrocerebellarcysthadbeenincidentallydetectedonmagneticresonanceimaging (Figure, A). The lesion was consideredtobeofnosignificancewithregardtohersymptomsatthattimeand thus was left untreated. Neurologic examination findings were normal other than the presence of ataxia on the Romberg test. Fundus examination documented bilateral papilledema. Magnetic resonance imaging revealed a 45-cm retrocerebellar cyst compressing the cerebellum anteroinferiorly, resulting in tonsillar herniation and hydrocephalus (Figure, B and C). The patient underwent an urgentsuboccipitalcraniotomy.Intraoperatively, a bulging cyst containing a xanthochromic fluid was documented (Figure, D). Chemical analysis of the cyst fluid content revealed an elevated ferritin level of 21.4 ng/mL (to convert to picomoles per liter, multiply by 2.247), whereas the level of ferritin in the cerebrospinal fluid, which was independently collected from the cisterna magna, was normal at 6.8 ng/mL (12.0 is pathological). A wide resection of the cyst membranewasperformed,andthepathologicaldiagnosiswasconsistentwith an arachnoid cyst. The patient showed a full recovery after the operation. Follow-up magnetic resonance imaging confirmed shrinkage of the arachnoid cyst with resolution of the tonsillar herniation and hydrocephalus, and fundus examination confirmed the disappearance of bilateral papilledema 3 months after the operation. COMMENT Arachnoid cysts are incidentally detected in 2.6% of the pediatric population (aged 18 years). 1 Because progressive neurological signs secondary to growth of the lesion are rare, radiological follow-up and prophylactic surgery for asymptomatic arachnoid cysts are considered unnecessary. We are unaware of any published cases where both tonsillar herniation and hydrocephalus resulted from the growth of a posterior fossa arachnoid cyst. Examination of the ferritin concentration in the cerebrospinal fluid as a potential marker of previous subarachnoid bleeding showed a 3-fold elevation in the arachnoid cyst fluid compared with the cerebrospinal fluid in our case, which may reflect the preceding intracystic hemorrhage that can cause arachnoid cyst growth via an osmotic gradient. 2 The xanthochromic arachnoid cyst fluid in our case also seems to be suggestive of the previous intracystic bleeding.

Hydrocephalus and arachnoid cysts

The management of arachnoid cysts (AC) remains controversial. An additional problem derives from the management of hydrocephalus associated with an AC. In this work, we discuss existing procedures proposed in the current literature for their treatment. We reviewed selected reports on intracranial ACs placing special interest in those about the association of hydrocephalus and ACs. We also briefly surveyed data of our patients with this association. Hydrocephalus is often found in midline and posterior fossa ACs. Interhemispheric lesions may also evolve with ventriculomegaly, while middle fossa lesions rarely produce hydrocephalus. Patients' age, cyst location and size, and macrocephaly have all been related to the development of hydrocephalus. Some authors remark on the role played by hydrocephalus and hypothesize that some ACs would result from disturbed cerebrospinal fluid (CSF) dynamics. They also propose that ACs might represent a localized form of hydrocephalus. We also comment on hydrocephalus in relation to the diverse locations of ACs. Neuroendoscopic techniques have transformed previous ways of management as cystoperitoneal shunting and open fenestration. ACs may be pathogenetically related with hydrocephalus, and conversely, ACs may cause hydrocephalus. In some patients, aberrant CSF dynamics seems to play a major role in the development of both cyst and hydrocephalus. Hydrocephalus and ACs may be treated exclusively with neuroendoscopic procedures, although some patients will still require CSF shunting. The ideal option seems to consist of choosing the method that offers the highest success with a single procedure for treating the hydrocephalus and the AC simultaneously.

P03.12: Posterior fossa arachnoid cyst: value of mid‐sagittal view of the vermis

P03.12: Posterior fossa arachnoid cyst: value of mid‐sagittal view of the vermis

Posterior Fossa Malformations

Understanding embryologic development of the cerebellum and the 4th ventricle is essential for understanding posterior fossa malformations. Posterior fossa malformations can be conveniently classified into those that have a large posterior fossa and those with normal or small posterior fossa. Disorders associated with a large posterior fossa include classic Dandy-Walker malformation, Blake's pouch cyst, mega cisterna magna, and posterior fossa arachnoid cyst. Disorders associated with normal or small posterior fossa include Dandy-Walker variant, Joubert syndrome, tecto-cerebellar dysraphia, rhombencephalosynapsis, the neocerebellar hypoplasias, and cerebellar atrophy. Neuro-imaging features should enable the imager to provide the referring physician a logical approach to these complex posterior fossa malformations.

Cyst-ventricle stent as primary or salvage treatment for posterior fossa arachnoid cysts

The optimal treatment of symptomatic posterior fossa arachnoid cysts is controversial. Current options include open or endoscopic resection, fenestration, or cyst-peritoneal shunt placement. There are potential drawbacks with all options. Previous authors have described stenting a cyst into the ventricular system for supratentorial lesions. The current authors have used a similar strategy for posterior fossa cysts. The authors performed a retrospective review of 79 consecutive patients (1993-2010) with surgically treated intracranial arachnoid cysts. The authors identified 3 patients who underwent placement of a stent from a posterior fossa arachnoid cyst to a supratentorial ventricle. In 2 patients the stent construct consisted of a catheter placed into a posterior fossa arachnoid cyst and connecting to a lateral ventricle catheter. Both patients underwent stent placement as a salvage procedure after failure of open surgical fenestration. In the third patient a single-catheter cyst-ventricle stent was stereotactically placed. All 3 patients improved clinically. Two patients remained asymptomatic, with radiographic stability in a follow-up period of 1 and 5 years, respectively. The third patient experienced initial symptom resolution with a demonstrable reduction of intracystic pressure. However, he developed recurrent headaches after 2 years. Posterior fossa cyst-ventricle stenting offers the benefits of ease of surgical technique and a low morbidity rate. It may also potentially reduce the incidence of shunt-related headaches by equalizing the pressure between the posterior fossa and the supratentorial compartments. While fenestration is considered the first-line therapy for most symptomatic arachnoid cysts, the authors consider cyst-ventricle stenting to be a valuable additional strategy in treating these rare and often difficult lesions.

Endoscopic fenestration of a cerebellopontine angle arachnoid cyst resulting in complete recovery from sensorineural hearing loss and facial nerve palsy

Cerebellopontine angle arachnoid cysts are usually asymptomatic, but are frequently found incidentally because of increased use of neuroimaging. Nevertheless, as these cysts enlarge, they may compress surrounding structures and cause neurological symptoms. Patients may present with vague, nonspecific symptoms such as headache, nausea, vomiting, and vertigo. Cranial nerve palsies, including sensorineural hearing loss and facial weakness, although rare, have also been reported in association with posterior fossa arachnoid cysts. Although surgery for these entities is controversial, arachnoid cysts can be treated surgically with open craniotomy for cyst removal, fenestration into adjacent arachnoid spaces, shunting of cyst contents, or endoscopic fenestration. Reversal of sensorineural hearing loss following open craniotomy treatment has been described in the literature in only 1 adult and 1 pediatric case. Improvement in facial weakness has also been reported after open craniotomy and arachnoid cyst fenestration. The authors report the first case of complete recovery from sensorineural hearing loss and facial weakness following endoscopic fenestration in a patient with a cerebellopontine angle arachnoid cyst.

Foramen Magnum Arachnoid Cyst Induces Compression of the Spinal Cord and Syringomyelia: Case Report and Literature Review

It is very rare that a foramen magnum arachnoid cyst induces compression of the spinal cord and syringomyelia, and currently there are few treatment experiences available. Here we reported the case of a 43-year-old male patient who admitted to the hospital due to weakness and numbness of all 4 limbs, with difficulty in urination and bowel movement. MRI revealed a foramen magnum arachnoid cyst with associated syringomyelia. Posterior fossa decompression and arachnoid cyst excision were performed. Decompression was fully undertaken during surgery; however, only the posterior wall of the arachnoid cyst was excised, because it was almost impossible to remove the whole arachnoid cyst due to toughness of the cyst and tight adhesion to the spinal cord. Three months after the surgery, MRI showed a reduction in the size of the arachnoid cyst but syrinx still remained. Despite this, the symptoms of the patient were obviously improved compared to before surgery. Thus, for the treatment of foramen magnum arachnoid cyst with compression of the spinal cord and syringomyelia, if the arachnoid cyst could not be completely excised, excision should be performed as much as possible with complete decompression of the posterior fossa, which could result in a satisfying outcome.

Posterior fossa arachnoid cysts and cerebellar tonsillar descent: short review

The objective of this study was to analyze the association of cerebellar tonsillar descent and syringomyelia in patients with posterior fossa arachnoid cysts. We reviewed the medical records of ten patients (mean, age 33; range, 24-49 years) diagnosed with posterior fossa arachnoid cyst and tonsillar descent. Symptoms evolved over a mean of 12 months (range, 6 months to 3 years). Syringomyelia was present in six cases. Six patients underwent a suboccipital craniectomy, three cases underwent an additional C1 laminectomy, and a further case had a limited craniectomy and tonsillar reduction. Three patients were also treated for hydrocephalus: one with a ventriculoperitoneal shunt and two with endoscopic third ventriculostomy. Two patients had conservative treatment. The posterior fossa arachnoid cysts were located at the vermis-cisterna magna (n = 4), the cerebellar hemispheres (n = 2), the cerebellopontine angle (n = 3), and the quadrigeminal cistern (n = 1). A patient with achondroplasia showed features of platybasia. Associated malformations included craniofacial dysmorphism in a patient diagnosed of trichorhinophalangeal syndrome and a case with a primary temporal arachnoid cyst. After a mean follow-up of 2 years (range, 3 months to 5 years), four patients showed resolution of their neurological symptoms, and two exhibited persisting ocular findings. Headaches and nuchalgia improved in four cases and persisted in four. Syringomyelia was resolved in four patients and improved in two. Patients harboring a posterior fossa arachnoid cyst may evolve with acquired Chiari malformation and syringomyelia. Initial management should be directed to decompressing the foramen magnum and should include the resection of the arachnoid cyst's walls. A wait-and-see attitude can be implemented in selected cases. In our experience, hydrocephalus should be properly addressed before treating the arachnoid cyst.

Subjectively quantified Maddox rod testing improves diagnostic yield over alternate cover testing alone in patients with diplopia

We aimed to assess the added diagnostic value of subjectively-quantified red Maddox rod testing in patients with diplopia or suspected strabismus. Over 9 months we compared measures of ocular alignment (inspection; alternate cover; Maddox rod) with final anatomic and etiologic diagnoses using clinical records in a cross-sectional study in an academic neuro-ophthalmology unit. Seventy-seven consecutive patients (98 visits) met study criteria. Mean age was 54 years (range 11–100 years). Most visits (73%) were for symptomatic diplopia and all three measures of alignment were generally available (92%). Maddox findings prompted additional diagnostic tests for 13 patients, leading to an important new diagnosis (systemic vasculitis; posterior fossa arachnoid cyst with mass effect; cavernous sinus mass) in three patients (4%). Maddox rod testing may add clinically relevant diagnostic information to that obtained by alternate cover testing alone. Its use might help prevent missed diagnoses in the evaluation of patients with diplopia or suspected strabismus.

Posterior Fossa Arachnoid Cyst Associated with Chiari I and Syringomyelia

Posterior Fossa Arachnoid Cyst Associated with Chiari I and Syringomyelia

Recovery of sensorineural hearing loss following operative management of a posterior fossa arachnoid cyst

Arachnoid cysts are benign, intraarachnoid cysts filled with cerebrospinal fluid that are usually encountered in the middle cranial fossa. If present in the posterior fossa, they usually produce nonspecific signs and symptoms such as headaches, dizziness and vertigo. We report the rare presentation of a young girl with right-sided sensorineural hearing loss and tinnitus secondary to a right cerebellopontomedullary arachnoid cyst. The patient underwent a suboccipital retrosigmoid (retromastoid) craniectomy with fenestration of the arachnoid cyst. Subsequently, the patient experienced improvement in hearing with near-complete resolution of sensorineural hearing loss. To the authors' knowledge, postoperative near-complete resolution of hearing loss secondary to posterior fossa arachnoid cysts in a pediatric patient has not been previously reported. The authors also review the literature with respect to posterior fossa arachnoid cysts and discuss their clinical features, diagnosis, and management.

Endoscopic therapy for obstructive hydrocephalus caused by cysts in the pathway of CSF circulation

To explore the process and technique of neuroendoscopic operation to treat obstructive hydrocephalus caused by cysts located in the pathway of CSF circulation. The cine MRI examinations and endoscopic operations were taken to treat 30 cases with obstructive hydrocephalus. Among all the cases, there are 11 intraventricular cysts (8 lateral ventricular cysts, 4 fourth ventricular cysts), 4 suprasellar arachnoid cysts, 1 quadrigeminal cistern arachnoid cyst, 6 Dandy-Walker malformations and 8 posterior fossa arachnoid cysts. CSF dynamic of all patients improved to different extents post-operation. It was observed that CSF passed through the stoma after ETV in all patients. The volume of 9 intraventricular cysts, 4 suprasellar arachnoid cysts, 1 quadrigeminal cistern arachnoid cyst and 4 posterior fossa arachnoid cysts diminished for different degrees. There were no surgery-related serious complications or deaths. There were not cyst enlarged and stoma obstructed cases. Obstructive hydrocephalus caused by cysts in the pathway of CSF circulation is the optimal indication for neuro-endoscopic surgery. After resecting cyst partially, we should take the endoscopic third ventriculostomy to rebuild the passway of CSF and elevate the cranial compliance. Cine MRI and radionuclide cisternography are helpful to understand the CSF dynamic and absorption.

Endoscopic management of posterior fossa arachnoid cyst in an adult: case report and technical note

The authors report a case of large arachnoid cysts of the posterior fossa treated by endoscopic surgery. A 40-year-old man was admitted with a 3-month history of headache and progressive gait imbalance, with no significant medical history. At the time of admission, neurological examination revealed no abnormalities except for tandem imbalance. Brain computerized tomography (CT) scan and magnetic resonance imaging (MRI) revealed a posterior fossa arachnoid cyst (PFAC) causing brain stem compression accompanied by hydrocephalus. The patient was treated by endoscopic fenestration of the cyst with a paramedian suboccipital transcortical approach. Postoperatively the patient's complaints showed improvement and he was discharged with no complications. Follow up MRI showed a decrease in the cyst's size and the hydrocephalus with decompression of the brain stem.

A differential diagnosis in postural headache: herniation of a giant posterior fossa arachnoid cyst

The causes of postural headache are usually associated with low intracranial pressure. However, there are still rare causes of posture-related headaches that are not associated with low intracraninal pressure and caused by pathologic processes. Herein, we report a patient with giant posterior fossaarachnoid cyst herniating below the level of foramen magnum presenting with postural headache, which has not been described previously in the literature. Emergency physicians should be aware that posterior fossa arachnoid cysts should be considered one of the differential diagnoses in patients with postural headache.

Clinical features of epilepsy in patients with cerebellar structural abnormalities in a referral center

The objective of this study was to describe epilepsy localization, clinical features and surgery outcome in patients with epilepsy and cerebellar structural abnormalities. We identified 10 patients with cerebellar lesions and epilepsy from our epilepsy database. Patients with only cerebellar atrophy were excluded. Medical records were reviewed for demographic data, seizure history, examination findings, EEG findings, epilepsy treatment and course. We reviewed imaging data for cerebellar structural findings, as well as cerebral abnormalities. Out of 2288 epilepsy patients in the database, 10 had epilepsy and cerebellar structural abnormalities other than atrophy. Their ages ranged from 26 to 52 years. The most common cerebellar malformations included Dandy-Walker malformation, cerebellar tumors and posterior fossa arachnoid cyst. Epilepsy was classified as generalized in one patient. Nine patients had focal epilepsy: the localization was temporal in five, frontal in one, occipital in one, and unclassified in two. A cerebral structural abnormality considered responsible for epilepsy was identified in six patients; four had hippocampal sclerosis, one had a hippocampal malformation, and one had a temporal pole cortical malformation. Presurgical evaluation was done in six patients. Surgery was performed in five, with excellent outcome in four. In this small series, epilepsy associated with cerebellar malformations was usually focal, most often with a temporal lobe focus. The cerebellar lesions did not adversely affect surgical success.

Regression of syringomyelia and tonsillar herniation after posterior fossa arachnoid cyst excision: Case report and literature review

Regression of syringomyelia and tonsillar herniation after posterior fossa arachnoid cyst excision: Case report and literature review

Evaluation of the management of arachnoid cyst of the posterior fossa in pediatric population: experience over 27 years

The necessity of surgical treatment of the arachnoid cyst in general and posterior fossa arachnoid cyst (PFAC) in particular is sometimes controversial. Surgery is warranted in symptomatic patients. In this study, we evaluated our experience throughout 27 years in the management of patients with PFAC. The study was designed with special emphasis on clinical features, surgery, and outcome. We investigated a total of 112 arachnoid cysts. Of them, 23 patients were symptomatic for PFAC. We assessed clinical characteristic and outcome for all patients. We obtained information from medical records and outpatient charts on age, sex, presenting symptoms, associated abnormalities, psychomotor status, modality of treatment, complications and follow-up in 23 patients (9 boys, 14 girls, ages 1 day-6 years) who had been admitted for evaluation and treatment of PFAC at Kobe Children's Hospital between 1978 and 2004. The mean follow-up period was 93 months (range 5-313 months). More than half of the patients had a history of increased head size and signs of intracranial pressure as presenting symptoms. One-third of the patients had associated abnormalities and six patients (26%) presented hydrocephalus. Computed tomography cisternography displayed delayed filling of the cyst in 11 patients (48%). All patients were treated surgically; the total number of surgical procedures was 55 with a surgical rate of 2.4 per patients. The marsupialization and marsupialization with cyst-peritoneal (C-P) shunt were the most common open surgical procedure in 14 and 5 patients, respectively. Endoscopic cysternostomy was performed in three patients. In our series, 25 (45%) of 55 surgical procedures included shunt malfunction and removal. The marsupialization of the cyst wall was successful in 9 of 14 operated patients (64%); the other five patients needed additional C-P or ventriculoperitoneal (V-P) shunt. Marsupialization with cyst-peritoneal shunt was successful in only one of five patients (20%), and for the other four patients, additional C-P or V-P shunt was necessary. No mortality is reported. Eight patients presented minor surgical morbidities that were resolved conservatively. The relatively good results using marsupialization or endoscopic cisternostomy as surgical procedure and the high incidence of shunt malfunction buttresses our use of both operations as a first-line surgery at present. Surgical procedure that does not include shunting decreases the ratio of recurrent operation because this kind of complication develops over time and should be consider as a second-line procedure.