Bilateral temporal arachnoid cysts in neurofibromatosis

Coexistence of Trigonocephaly and Sylvian Arachnoid Cysts: A Coincidence?

INTRODUCTION

The association between trigonocephaly and Sylvian fissure arachnoid cysts (ACs) has been occasionally reported in the literature. However, the real incidence of this association and its clinical relevance remain unknown.

METHODS

The authors collected and retrospectively reviewed all clinical charts and CT scans of patients surgically treated for trigonocephaly at the Pediatric Neurosurgical Department of Fondazione Policlinico Universitario "Agostino Gemelli" IRCCS from January 2014 to June 2023.

RESULTS

During the study period, 136 patients with trigonocephaly underwent surgery. Analysis of the clinical charts revealed that in 39.7% of the cases (54/136), preoperative CT scan depicted the presence of a Sylvian fissure AC. Of these, AC was bilateral in 23 cases and unilateral in the remaining 31. All unilateral ACs were on the left side. The ACs were classified as Galassi grade I in 52 cases (96.3%) and Galassi grade II in 2 cases (3.7%). Interestingly, in 1 case we reported a Galassi grade I AC enlargement during follow-up, thereby necessitating surgical fenestration.

CONCLUSION

ACs and trigonocephaly are well-known conditions for pediatric neurosurgeons; however, their association is poorly defined. Despite the lack of reports on the incidence and clinical significance of this association, it is worth knowing that radiological follow-up is essential in monitoring AC evolution.

Arachnoid cysts in paediatrics

PURPOSE OF REVIEW

Arachnoid cysts are incidentally found on neuroimaging at an increasing rate in the paediatric population. Hence, learning their clinical implications to better inform families is important. The purpose of this review is to outline the current understanding of epidemiology, disease and clinical features based on location, imaging and management of arachnoid cysts in paediatrics.

RECENT FINDINGS

The prevalence of arachnoid cysts is 2.6% in paediatrics, with greater than 90% being asymptomatic. When they do cause symptoms, it is based primarily on their location and size. The most accurate diagnostic modality is MRI. Recent literature focuses primarily on the origin of arachnoid cysts, new approaches to treating symptomatic arachnoid cysts and long-term implications for patients.

SUMMARY

Incidental arachnoid cysts are being found most often due to the more frequent use of neuroimaging. There is a higher prevalence for arachnoid cysts in men and they are more commonly found on the left side. Despite their impressive size or location, greater than 90% of these lesions are asymptomatic and require no intervention. However, follow up with neurosurgery to help determine the clinical significance of these lesions is essential.

Neurological manifestations of neurofibromatosis type 1: our experience

INTRODUCTION

Neurofibromatosis type 1 (NF1) is a progressive multisystem disorder following an autosomal dominant inheritance pattern that presents with multiple neurological manifestations.

METHODS

We reviewed medical histories of patients with NF1 followed up at our hospital's paediatric neurology department from May 1990 to 31 December 2018. We collected data on neurological symptoms.

RESULTS

A total of 128 patients with NF1 were identified. Mean age (SD) at NF1 diagnosis was 4.43 (3.38) years (range, 0.5-14.5 years). There was a slight female predominance (53.1%). Macrocephaly (head circumference over 2 SDs above average for age) was present in 37.5% of cases. Attention-deficit/hyperactivity disorder was recorded in 28.9% of patients (37): combined type in 20 patients, predominantly inattentive in 15, and predominantly impulsive/hyperactive in 2. Other manifestations included headache (18.6%), cognitive impairment (7.8%), motor deficit (6.2%), and epilepsy (4.68%). Brain MRI was performed in 85 patients, revealing T2-weighted hyperintensities in the basal ganglia and/or cerebellum in 60 patients (70.5%), Chiari malformation type 1 in 4 cases, and arachnoid cysts in 3. Optic nerve gliomas were identified by MRI in 22 patients (25.8%). Other MRI findings included plexiform neurofibromas (9.3%) and central nervous system gliomas (3.1%).

CONCLUSIONS

The neurological manifestations identified in our sample are consistent with those reported in the literature. Effective transfer strategies from paediatric neurology departments and subsequent clinical follow-up by adult neurology departments are needed to prevent loss to follow-up in adulthood.

[Epidemiology and classification of arachnoid cysts in children]

The prevalence of arachnoid cysts in children is 1-3%. They are more frequent in boys. They can be located intracranially or in the spine. Intracranial cysts are classified as supratentorial, infratentorial, and supra-infratentorial (tentorial notch). Supratentorial are divided into middle cranial fossa, convexity, inter-hemisferic, sellar region, and intraventricular. Infratentorial are classified into supracerebellar, infracerebellar, hemispheric, clivus, and cerebellopontine angle. Finally spinal arachnoid cysts are classified taking into account whether they are extra- or intradural, and nerve root involvement.

Outcome of 12 antenatally diagnosed fetal arachnoid cysts: case series and review of the literature

OBJECTIVES

To investigate the natural history, associated abnormalities and outcome of 12 fetuses with arachnoid cyst diagnosed antenatally by ultrasound and magnetic resonance imaging and to compare the outcome with cases in the literature.

METHODS

A retrospective study of all cases of antenatally detected fetal arachnoid cysts was performed in patients referred to a tertiary unit between 2007 and 2013. Associated abnormalities, pregnancy outcome and postnatal follow-up were analyzed. All papers about prenatally diagnosed arachnoid cysts, of the last 30 years, were evaluated (search terms in Pubmed: "prenatal diagnosis", "Arachnoid Cysts").

RESULTS

Fetal arachnoid cysts were diagnosed in 12 fetuses, 9 were females. The mean gestational age of diagnosis was 28 1/7 (range 19 1/7-34 2/7 weeks). A total of 9 cases were supratentorial, 3 were located in the posterior fossa. In 10 cases a fetal MRI was performed which confirmed brain compression in 4 out of 5 supratentorial arachnoid cyst. MRI did not reveal other malformations nor signs of nodular heterotopia. Only one fetus presented with additional major anomalies (bilateral ventricumomegaly of >20 mm and rhombencephalosynapsis) leading to a termination of pregnancy. Two neonates underwent endoscopic fenestration of the arachnoid cyst in the first week of life with no additional intervention in childhood. All but one (10/11) had a favorable postnatal outcome. This child suffered from visual impairment at autism was diagnosed at the age of 5. One child had a surgical correction of strabismus later in childhood. In one child the infratentorial arachnoid cyst regressed spontaneously on ultrasound and MRI in the postnatal period.

CONCLUSIONS

The majority of arachnoid cysts in this series are of benign origin and remain stable. Based on the current series and the review of the literature, in the absence of other associated anomalies and when the karyotype is normal, the postnatal overall and neurological outcome is favorable. Large suprasellar arachnoid cysts however, may cause visual impairment and endocrinological disturbances. Rarely associated cerebral or cerebellar malformations are present. Modern postnatal management of suprasellar arachnoid cyst consists of endoscopic cystoventriculostomy.

Prevalence and natural history of arachnoid cysts in adults

Object

Arachnoid cysts are a frequent finding on intracranial imaging. The prevalence and natural history of these cysts in adults are not well defined.

Methods

We retrospectively reviewed the electronic medical records of a consecutive series of adults who underwent brain MRI over a 12-year interval to identify those with arachnoid cysts. The MRI studies were reviewed to confirm the diagnosis. For those patients with arachnoid cysts, we evaluated presenting symptoms, cyst size, and cyst location. Patients with more than 6 months' clinical and imaging follow-up were included in a natural history analysis.

Results

A total of 48,417 patients underwent brain MRI over the study period. Arachnoid cysts were identified in 661 patients (1.4%). Men had a higher prevalence than women (p < 0.0001). Multiple arachnoid cysts occurred in 30 patients. The most common locations were middle fossa (34%), retrocerebellar (33%), and convexity (14%). Middle fossa cysts were predominantly left-sided (70%, p < 0.001). Thirty-five patients were considered symptomatic and 24 underwent surgical treatment. Sellar and suprasellar cysts were more likely to be considered symptomatic (p < 0.0001). Middle fossa cysts were less likely to be considered symptomatic (p = 0.01. The criteria for natural history analysis were met in 203 patients with a total of 213 cysts. After a mean follow-up of 3.8 ± 2.8 years (for this subgroup), 5 cysts (2.3%) increased in size and 2 cysts decreased in size (0.9%). Only 2 patients developed new or worsening symptoms over the follow-up period.

Conclusions

Arachnoid cysts are a common incidental finding on intracranial imaging in all age groups. Although arachnoid cysts are symptomatic in a small number of patients, they are associated with a benign natural history for those presenting without symptoms.

The intracranial arachnoid mater : a comprehensive review of its history, anatomy, imaging, and pathology

INTRODUCTION

The arachnoid mater is a delicate and avascular layer that lies in direct contact with the dura and is separated from the pia mater by the cerebrospinal fluid-filled subarachnoid space. The subarachnoid space is divided into cisterns named according to surrounding brain structures.

METHODS

The medical literature on this meningeal layer was reviewed in regard to historical aspects, etymology, embryology, histology, and anatomy with special emphasis on the arachnoid cisterns. Cerebrospinal fluid dynamics are discussed along with a section devoted to arachnoid cysts.

CONCLUSION

Knowledge on the arachnoid mater and cerebrospinal fluid dynamics has evolved over time and is of great significance to the neurosurgeon in clinical practice.

Arachnoid cysts

Arachnoid cysts are fluid-filled duplications or splittings of the arachnoid layer with a content which is similar but not equal to the cerebrospinal fluid. Arachnoid cysts are not actual neurodegenerative disorders, rather the underlying defect of the texture of the arachnoid layer is probably congenital in nature. They can occur sporadically or can be associated with other malformations or diseases. Arachnoid cysts may be discovered in early childhood. However, they can develop de novo, grow or decrease in size. They may be diagnosed by ultrasound screening in the fetal period or be discovered during childhood or adulthood. Many arachnoid cysts are asymptomatic.Treatment strategies are discussed controversially. If they are diagnosed incidentally or are correlated with only very mild symptoms, a conservative management with follow-up imaging may be favored. If they grow, they can cause headaches, seizures or other neurological symptoms and require neurosurgical treatment. This chapter addresses aspects of pathogenesis, clinical symptoms, indication for neurosurgical treatment and treatment options.

Bilateral temporal arachnoid cysts associated with tuberous sclerosis complex

The association between tuberous sclerosis complex and intracranial abnormalities such as hemimegalencephaly, schizencephaly, intracranial arterial aneurysms, and corpus callosum agenesis/dysplasia has been reported in the recent literature. However, the association between tuberous sclerosis complex and bilateral temporal arachnoid cysts has not been reported. A case of an 8-year-old boy with a mental impairment and epileptic seizures that began 5 years earlier is presented. The neuro-radiological findings are consistent with tuberous sclerosis complex associated with bitemporal arachnoid cysts. His epileptic seizures were treated with antiepileptic medications. To the authors' knowledge, this is the first reported case of tuberous sclerosis complex associated with bilateral arachnoid cysts of the temporal region. In such cases, arachnoid cysts may exacerbate the clinical picture.

Posterior fossa arachnoid cysts can mimic Meniere’s disease

Arachnoid cysts constitute 1% of all intracranial space-occupying lesions. In the posterior fossa, they typically produce vague, nonspecific symptoms. However, a subset of these lesions can produce signs and symptoms indistinguishable from those of Meniere's disease. We discuss the clinical and laboratory features of 2 cases of posterior fossa arachnoid cysts mimicking Meniere's disease as well as the substantial resolution of symptoms in 1 patient after cysto-peritoneal shunt. Posterior fossa arachnoid cyst must be considered in the differential diagnosis of patients presenting with signs and symptoms of Meniere's disease.

Familial arachnoid cysts in association with autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is a systemic disorder well-known for its association with intracranial aneurysms. Recently, intracranial arachnoid cysts have also been reported to be associated with ADPKD. We describe a father and daughter who each has a posterior fossa arachnoid cyst and asymptomatic ADPKD. To our knowledge, this is the first report of familial occurrence of arachnoid cysts in association with ADPKD.

Intracranial arachnoid cysts in children: a review of pathogenesis, clinical features, and management

Arachnoid cysts are developmental anomalies that are most often diagnosed in childhood. They are often discovered as incidental findings found on imaging. Occasionally they may produce symptoms because of expansion or bleeding. There may be underlying maldevelopment of the cortex especially the temporal lobe. There is controversy regarding the role and the type of surgery indicated in its treatment. Recent descriptions of aphasia and attention-deficit disorders associated with these cysts indicate that we do not fully understand this entity. There is also no acceptable explanation for the male preponderance and increased incidence on the left side. The distribution, clinical features, treatment modalities, and some unusual syndromes associated with arachnoid cysts in children are discussed in this review.

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.

Bilateral medial temporal lobe damage without amnesic syndrome: a case report

After the case report H.M. [42], unilateral neurosurgical interventions in the mediotemporal area have no longer been performed, if damage to the contralateral mediotemporal region was present, because of running the risk of provoking a postoperative amnesic syndrome. We present a patient with bilateral mediotemporal cysts and medically refractory complex partial seizures originating in the left mediotemporal region. Although our patient had additional right mediotemporal damage and poor non-verbal learning and memory, the left amygdaloid body and the left hippocampal formation were resected because the patient passed a selective anterior temporal lobe Amobarbital test. Postoperatively, our patient's non-verbal memory recovered to normal, but his verbal memory declined. Nevertheless, he was non-amnesic and seizure-free.

Intracranial cysts in autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is a systemic disorder well known for its association with intracranial aneurysms. A series of patients with ADPKD who were screened for the presence of an intracranial aneurysm were reviewed and found to include an unexpectedly high number with intracranial arachnoid cysts. Among 247 patients with ADPKD who underwent magnetic resonance imaging (180 cases) or high-resolution contrast-enhanced computerized tomography (67 cases), there were 151 women and 96 men with a mean age of 44 years. Intracranial arachnoid cysts were found in 20 patients (8.1%) with ADPKD compared to two (0.8%) in a control group without ADPKD matched for age, sex, and method of imaging (p < 0.0001). Multiple intracranial arachnoid cysts were found in two patients. Polycystic liver disease was present in 17 (85.0%) of the 20 patients with intracranial arachnoid cysts compared to 119 (52.4%) of the 227 patients without (p < 0.004). Pineal cysts were found in two patients (0.8%) and choroid plexus cysts were found in three patients (1.2%) but this was not different from the control population. None of the intracranial cysts was symptomatic and none was treated surgically. Intracranial arachnoid cysts are a relatively frequent incidental finding in patients with ADPKD, providing further support for the systemic nature of this disease. In the authors' experience with approximately 1500 patients with ADPKD, no complication has been encountered from an intracranial arachnoid cyst, suggesting that asymptomatic intracranial arachnoid cysts in patients with ADPKD require no treatment.

Spontaneous carotid-jugular fistula and carotid dissection in a patient with multiple intracranial arachnoid cysts and hemifacial atrophy: a generalized connective tissue disorder? Case report

The authors report a case of a 45-year-old woman with pulsatile tinnitus who was found to have an unusual spontaneous fistula between the petrous internal carotid artery and internal jugular vein. The fistula resolved spontaneously, possibly related to daily manual compression of the ipsilateral common carotid artery. The patient also had a contralateral carotid artery dissection, multiple intracranial arachnoid cysts, and hemifacial atrophy. Her medical history was significant for easy bruisibility, abnormal scarring, and mitral valve prolapse. This association appears unique and may represent a previously underscribed generalized connective tissue disorder.

Absence of the greater sphenoid wing in neurofibromatosis type I: congenital or acquired: case report

unilateral absence of the greater wing of the sphenoid bone is a distinctive but uncommon manifestation of Type I neurofibromatosis, which has until now been regarded as a developmental anomaly of mesodermal origin. A computed tomographic scan was obtained in a 4-week-old infant with an abnormal left eye. The scan demonstrated an intact ipsilateral sphenoid bone, except for minor expansion of the medial end of the left superior orbital fissure. Another computed tomographic scan was obtained 6 years later, when the child had café-au-lait patches, axillary freckling, Lisch nodules, and left phthisis bulbi. This later scan showed typical sphenoid dysplasia. Much of the greater wing was absent, and the anterior temporal pole was displaced anteriorly. In this article, we discuss the implications of this case in terms of the cause of this condition and the diagnosis of Type I neurofibromatosis.