Bilateral middle cranial fossa arachnoid cysts. A case report.

The temporal lobe agenesis syndrome is a rare congenital abnormality. This syndrome frequently has been described in association with arachnoid cysts or abnormal collections of cerebrospinal fluid. Arachnoid cysts develop most frequently in the middle cranial fossa and almost all these cysts are unilateral. Bilateral middle cranial fossa arachnoid cysts are extremely rare and only 9 cases have been reported in the literature. We present an adult case with bilateral arachnoid cysts and temporal lobe agenesis whose mental examination and neurologic assessment is normal. The cysts are demonstrated by CT and metrizamid CT cysternography.     

中颅窝蛛网膜囊肿的神经内镜手术治疗

目的 探讨中颅窝蛛网膜囊肿神经内镜手术的治疗经验并评估其治疗效果.方法 回顾2004年1月至2009年6月使用神经内镜行囊肿-脑池造瘘治疗中颅窝蛛网膜囊肿32例,其中男性21例,女性11例,年龄6个月～39岁,平均年龄8.4岁,包括5例幼儿患者,年龄2～5岁.分析病例的临床资料,包括临床症状、影像学表现、手术适应证、手术技巧、手术并发症以及临床及影像学随访结果 .结果 患者术后随访时间8～72个月,术前有症状的27例患者中,症状消失8例、改善17例、无变化2例,临床症状好转率为92.6%.5例术前无症状的幼儿患者,术后随访无新症状出现.囊肿消失4例,缩小20例,无明显变化8例.术后颅内感染及切口脑脊液漏各1例.无症状硬脑膜下积液4例.并发症发生率为18.8%.结论 神经内镜手术损伤小、效果好,可以作为中颅窝蛛网膜囊肿的首选治疗方法 .     

Arachnoid cysts of the middle cranial fossa.

Arachnoid cysts of the middle cranial fossa may present clinically in several different ways. They may remain asymptomatic throughout life, or may cause only local bulging of the skull, with or without exophthalmos. Expansion of the cyst may occur through a ball-valve mechanism of its membrane in communication with the general subarachnoid space leading to increased intracranial pressure with or without localizing neurological deficits. Finally, such cysts are associated with increased vulnerability to the effects of head injury, resulting in hemorrhage either into the cyst or external to the cyst to form a subdural hematoma. Recognition of these various manifestations is essential to proper treatment.     

Posterior fossa arachnoid cysts.

Arachnoid cysts of the posterior fossa are rare lesions that are considered to be mostly congenital in origin. In this article, we retrospectively review 12 patients who underwent surgical treatment for their symptomatic posterior fossa arachnoid cysts. The most common presenting symptoms were gait disturbances and headache. The diagnosis was established on computed tomography or magnetic resonance imaging. Surgery consisted of cyst wall excision with fenestration in nine cases and shunting procedures in three cases. In all cases except one who-died, the postsurgical follow-up neuroradiological investigations showed that the cysts had decreased in size, the cerebellum had re-expanded, and if there was preoperative hydrocephalus, the ventricular size was decreased. The follow-up period ranged from 1 to 11 years. All surviving cases are free of symptoms and no arachnoid cysts recurred. The classification, pathophysiology, differential diagnosis and surgical treatment of infratentorial arachnoid cysts are discussed and the relevant literature is reviewed.     

Unusual computed tomographic findings in a case of arachnoid cyst in the middle cranial fossa

A rare case is reported of arachnoid cyst in the middle cranial fossa associated with intracystic hemorrhage and subdural hematoma. The preoperative computed tomography scans showed no difference in density among the cyst, the hematoma, and the brain parenchyma. The serial computed tomography scans after the accident were the most helpful in making the correct diagnosis.     

Paramedian hourglass epidermoid cysts extending in the middle and posterior cranial fossa

Four cases of large paramedian hourglass epidermoid tumors extending both in the middle and posterior cranial fossa are reported and other 16 cases from the literature are reviewed. The length of the clinical history and the triviality of neurological symptoms in spite of the size of the tumor are emphasized. CT scanning well documents the extension of these epidermoids and usually consents to differentiate them from the arachnoid cysts. The subtemporal transtentorial approach is more advisable, although a two-stage operation by subtemporal and suboccipital route can be necessary in some cases. Nevertheless the difficulties and the risk of the surgical treatment make very hard the complete removal of the tumor in most cases.     

A case of arachnoid cyst in the middle cranial fossa presenting with trigeminal neuralgia

A 50-year-old man had been suffering from left trigeminal neuralgia for 30 years. CT scan revealed an arachnoid cyst occupying the anterior two-thirds of the left middle cranial fossa. Cerebral angiography showed elevation of the left middle cerebral artery and medial shift of the left posterior cerebral artery. Metrizamide CT showed that the cyst was not communicating with the subarachnoid space. Air CT revealed the root of the left trigeminal nerve in contact with the arachnoid cyst. The patient became completely free from the trigeminal neuralgia 6 months after cystoperitoneal shunt. This case seems to be a very rare case of trigeminal neuralgia caused by an arachnoid cyst.     

Clinical study on intracranial arachnoid cyst: with reference to the middle cranial fossa

Thirty-two cases of congenital arachnoid cyst (AC), 26 cases of supratentorial, and 6 cases of infratentorial cyst are reported. They were encountered over a period of 9 years. The 26 supratentorial cysts consisted of 21 cases located in the middle fossa, 2 in the frontal, and 3 in the suprasellar. Patients' ages ranged from 7 months to 67 years (mean: 19.3 years), with a male to female ratio of 23:9. The most common symptoms were headache, epileptic seizure, and cranial enlargement. Based on observations between neuroradiological examinations including analysis of the cyst content, and operation, typical AC might be defined as "duplicated arachnoid and its splitting", and it may be said that "there is continuous existence of cerebral structure such as cortex and white matter lying adjacent to AC on MRI". Out of 32 cases, 15 received surgical treatment because of mass effect of AC itself, abnormal dynamics of the AC fluid, and/or increasing sign of ICP. 13 cases had resection of AC outer membrane with craniotomy, and the remaining two had cystoperitoneal shunt. One of the shunting cases complicated subdural hematoma. Surgical treatment was discussed and radical craniotomy rather than a shunt procedure was preferred. Prognosis of all cases was favorable and uneventful.     

A case of neurogenic bladder due to arachnoid cyst of the middle cranial fossa

A 6-year-old girl, with urinary incontinence for the past 3 years, showed an overactive bladder and detrusor-sphincter dyssynergia (DSD) in urodynamic study. An epileptic focus in the right occipital area, as well as a large arachnoid cyst in the left middle cranial fossa was revealed by EEG and intracranial CT. After surgery for the arachnoid cyst, urinary incontinence was improved with disappearance of the epileptic focus in EEG, and an alteration of overactive bladder into normolactive one and improvement of DSD were observed in urodynamic study. It was considered that the urinary incontinence of this case might be associated with the ectopic epileptic focus due to the arachnoid cyst.     

Spontaneous disappearance of a large middle fossa arachnoid cyst

A case of a large middle fossa arachnoid cyst that spontaneously disappeared is reported. The possible mechanisms involved in the "natural cure" of this lesion and the indications for surgical versus conservative treatment of middle fossa arachnoid cysts are discussed.     

Endoscopic surgery for large posterior fossa arachnoid cysts.

The authors report two cases of large arachnoid cysts of the posterior fossa treated by endoscopic surgery. One patient underwent a successful endoscopic cyst fenestration by burr hole approach after several procedures of shunt revision. In another an endoscope-assisted microsurgical intervention was necessary. Lateral (cerebellar or cerebellopontine angle) cysts, as two reported cases, may be treated through a lateral retromastoid approach by fenestration into the prepontine cistern and eventually into the cisterna magna. We advise to start the operation through a burr hole and to try to realize the fenestration by endoscopy only. If this attempt fails, an endoscope-assisted microsurgical technique may be performed by enlarging the craniectomy. In this last instance the endoscope is useful particularly deeply to fenestrate the anterior cyst wall in the prepontine or ambient cisterns, where it provides more illumination and helps to identify the nervous and vascular structures.     

Extracerebral neural tissue mass in the middle cranial fossa extending into the oropharynx in a neonate. Case report

The authors report the case of a newborn baby girl who had a large extracerebral neural tissue mass in the right middle cranial fossa which extended into the oropharynx through an enlarged foramen ovale. The surgical specimen comprised various kinds of neural tissue, including primitive neuroepithelium, mature as well as immature neurons and glia, myelinated fibers, ependyma, choroid plexus, ocular pigmented epithelium, and a number of calcospherites. The mass was partially covered by its own leptomeninges. The question of whether this mass is a true neoplasm or a heterotopia is discussed.     

Bilateral cerebellopontine angle arachnoid cysts: case report

OBJECTIVE AND IMPORTANCE: A rare case of bilateral cerebellopontine angle (CPA) arachnoid cysts (ACs), accompanied by cerebellar tonsillar displacement toward the foramen magnum, is presented. CLINICAL PRESENTATION: A 45-year-old woman presented with progressive dysphagia, vertigo, and truncal ataxia. Magnetic resonance imaging revealed bilateral CPA ACs and cerebellar tonsillar displacement. INTERVENTION: The right CPA AC was excised via a suboccipital approach. Decompression of the foramen magnum and duraplasty were also performed. CONCLUSION: The case reported here is the first case of bilateral CPA ACs. Decompression of the foramen magnum and excision of the cyst resulted in complete relief of symptoms.     

Gender distribution and sidedness of middle fossa arachnoid cysts: a review of cases diagnosed with computed imaging.

According to earlier reports, arachnoid cysts seem to occur more frequently in males, and on the left side. The latter phenomenon could, however, be explained by a greater significance attributed to symptoms from the dominant hemisphere as a justification for invasive procedures in the pre-computed tomography era. The literature from the last third of the era of computed tomography is reviewed with respect to gender distribution and sidedness for middle fossa arachnoid cysts. Also included are a few cases of our own from the same period. It is evident from this survey of the literature, based on computed tomography studies, that there is a significant tendency for these cysts to occur in males, with a male/female ratio of nearly 3:1. This preponderance toward males could not be explained by the somewhat higher frequency of associated subdural hematomas that was found in male patients. The survey also showed that middle fossa arachnoid cysts occur or are detected significantly more frequently on the left side than on the right, with a ratio of 1.8:1.     

Simultaneous posterior and middle cranial fossa neurinomas

Summary A case of unilateral association of a neurinoma of the VIII nerve and a neurinoma of the temporal fossa in a 33-year-old woman without von Recklinghausen disease stigmata is presented.This uncommon association can mimic the picture of a trigeminal neurinoma with a dumb-bell extension into the posterior fossa.     

Diagnosis and treatment of arachnoid cysts of the posterior fossa

Arachnoid cysts of the posterior fossa are rare. When arachnoid cysts are encountered, the presenting symptoms are frequently otologic, with hearing loss and imbalance occurring commonly. Three cases are presented with a previously unreported otologic symptom, that of bilateral hearing loss, which in one case was fluctuant. None of the patients had the common symptoms of unilateral hearing loss and headache. With the advent of computed tomography and magnetic resonance imaging, these cysts may be readily identified, usually with diagnostic imaging alone. Unfortunately there is often a delay in diagnosis because of the vague and fleeting nature of the symptoms. Because no single diagnostic symptom pattern is able to characterize all cases, it is believed computed tomography or magnetic resonance imaging or both are indicated in patients with long-standing otologic complaints--even in the absence of unilateral symptoms. Treatment of posterior fossa arachnoid cysts primarily consists of surgical procedures designed to decompress the cyst. In this series, treatment with diuretics alone resulted in improvement of symptoms during several years of followup, with no evidence of enlargement of the cysts.     

Microsurgical keyhole approach for middle fossa arachnoid cyst fenestration

OBJECTIVE: The optimal surgical treatment for symptomatic temporal arachnoid cysts is controversial. Therapeutic options include cyst shunting, endoscopic fenestration, and craniotomy for fenestration. We reviewed the results for patients who were treated primarily with craniotomy and fenestration at our institution, to provide a baseline for comparisons of the efficacies of other treatment modalities. METHODS: A retrospective review of data for 50 children who underwent keyhole craniotomy for fenestration of temporal arachnoid cysts between 1994 and 2001 was performed after institutional review board approval. During that period, the first-line treatment for all symptomatic middle fossa arachnoid cysts was microcraniotomy for fenestration. Microsurgical dissection to create communications between the cyst cavity and basal cisterns was the goal. All patient records were reviewed and numerous variables related to presentation, cyst size and classification, treatment, cyst resolution, symptom resolution, follow-up periods, and cyst outcomes were recorded. RESULTS: Fifty temporal arachnoid cysts in 50 treated patients were identified. The average age at the time of surgery was 68 +/- 57.2 months. The follow-up periods averaged 36 months. There were 34 male and 16 female patients in the series. Twenty-six cysts were on the left side. Indications for surgery included intractable headaches (45%), increasing cyst size (21%), seizures (25%), and hemiparesis (8%). The symptoms most likely to improve were hemiparesis (100%) and abducens nerve palsies. Headaches (67%) and seizure disorders (50%) were less likely to improve. Nine patients exhibited progressive increases in cyst size in serial imaging studies. Those patients were monitored for a mean of 40 +/- 23 months before intervention. In the entire series, 82% of patients demonstrated decreases in cyst size in serial imaging studies. Of those patients, 18% demonstrated complete cyst effacement. Overall, 83% of patients with Grade II cysts and 75% of patients with Grade III cysts exhibited evidence of decreases in cyst size in long-term monitoring. Two patients required shunting after craniotomy (4%). Hospital stays averaged 3.4 days. Total surgical times averaged 115 minutes. No significant blood loss occurred (5-50 ml). Complications included spontaneously resolving pseudomeningocele (10%), transient Cranial Nerve III palsy (6%), cerebrospinal fluid leak (6%), subdural hematoma (4%), and wound infection (2%). CONCLUSION: A microsurgical keyhole approach to arachnoid cyst fenestration is a safe effective method for treating middle fossa cysts. This procedure can be performed with minimal morbidity via a minicraniotomy. Compared with an endoscopic approach, better control of hemostasis can be obtained, because of the ability to use bipolar forceps and other standard instruments. The operative time and length of hospital stay were not excessively increased.