Diverse arachnoid cyst morphology indicates different pathophysiological origins

Arachnoid cyst in the quadrigeminal cistern: A case from Afghanistan

Arachnoid cysts, fluid-filled lesions within the central nervous system, pose diagnostic challenges. This study examines a unique case of a quadrigeminal arachnoid cyst in a 13-year-old girl, emphasizing accurate identification and treatment. The patient's symptoms of blurred vision and headaches led to the discovery of papilledema and imaging revealing a sizable cyst causing obstructive hydrocephalus. Urgent surgical intervention involved suboccipital craniectomy and infratentorial-supracerebellar cyst drainage, resulting in favorable postoperative outcomes. Further analysis of anatomical variations, age-related factors, and etiological debates deepens understanding. Diagnostic advancements, notably MRI, are crucial for noninvasive characterization. This case offers nuanced insights into managing arachnoid cysts, highlighting the success of tailored surgical strategies. Recognizing clinical subtleties, utilizing diagnostic innovations, and customizing surgical techniques are essential for navigating complexities. This study underscores the importance of a comprehensive approach in addressing the challenges of arachnoid cysts within the central nervous system.

Growing and symptomatic intracranial arachnoid cyst in an elderly patient: a case report and literature review

We report an elderly patient with a symptomatic and growing arachnoid cyst. Physician should be cautious in counseling asymptomatic arachnoid cyst patients, regardless of their age, and inform them of the possibility, although rare, of growth and symptom development even in their late life.

An extradural cyst in a French Bulldog

CASE HISTORY

A 7-year-old, male neutered French Bulldog was referred to a specialist veterinary hospital for evaluation of progressive paraparesis of 6-months' duration. The owners reported both faecal and urinary incontinence at home.

CLINICAL FINDINGS

The dog presented with ambulatory paraparesis and pelvic limb ataxia that was more pronounced in the right pelvic limb. The pelvic limb withdrawal response and sciatic myotatic response were reduced bilaterally. Postural reaction responses were delayed in both pelvic limbs, and this was more obvious in the right pelvic limb. The anal tone and perineal sensation were normal at the time of examination.An L4-S3 myelopathy was suspected. CT of the spine revealed a compressive, bilobed, extramedullary, cyst-like structure within the vertebral canal, between L7 and S3. Surgical removal of the cyst via a L7-S1 dorsal laminectomy was performed. Histopathological examination and additional immunohistochemistry of the excised structure indicated a probable ependymal cyst with a ciliated lining. The dog recovered well post-operatively, and at follow-up 3 weeks later had some improvement of his neurological signs. The paraparesis and pelvic limb ataxia had improved; however, the remaining neurological examination was similar to the pre-surgical examination.

DIAGNOSIS

Extradural cyst.

CLINICAL RELEVANCE

Spinal cysts can contribute to clinical signs that resemble other common chronic spinal cord diseases, such as intervertebral disc disease. Therefore, this disease should be considered as a differential when dealing with cases of progressive paraparesis and pelvic limb ataxia. This case report may potentially provide opportunities in the future for further understanding of the pathogenesis, behaviour, outcomes and subclassification of spinal cysts in dogs.

Surgical indications in pediatric arachnoid cysts

INTRODUCTION

Arachnoid cysts are developmental lesions consisting of CSF collections within the subarachnoid space. There are many theories and hypotheses about their pathogenesis and histopathology and this may also explain the diversities seen in clinical behaviors of these cysts, their natural history and consequently their management where there is a great controversy about selecting patients for surgical intervention. The most common location in pediatrics is the Sylvian or middle cranial fossa and this made it gain more concern and greater debate about its management where its diagnosis is often accidently or associated with nonspecific symptoms.

AIM

Our aim in this article was to review the main surgical indications for pediatric arachnoid cysts in the literature.

CONCLUSION

We concluded that the decision for surgical intervention for pediatric arachnoid cysts is not a simple one and highly debatable and should be taken cautiously especially with sylvian arachnoid cysts that may reach a large size without symptoms. However, there is a consensus that the occurrence of symptoms definitely correlated to the presence of these cysts or their rupture with consequent subdural hematoma or hygroma are indications for surgical intervention. Large cysts in locations compressing CSF pathways causing hydrocephalus are also candidates for surgical fenestration. The surgical gain from prophylactic surgery is questionable particularly when asymptomatic.

Understanding intracranial arachnoid cysts: a review of etiology, pathogenesis, and epidemiology

Arachnoid cysts (AC) are one of the common pathologies encountered in pediatric neurosurgical settings. It comes to clinical attention more often incidentally but also more often than previously due to the wide availability of diagnostic imaging. However, the accurate incidence and prevalence remain unknown. There is an ongoing debate on symptomatology, indications of treatment, and best treatment modalities. In this review, we aimed to discuss the current general knowledge about the arachnoid cyst, focusing on the etiology, pathogenesis, and epidemiology. Specific findings related to locations, such as the Sylvian fissure, are also emphasized.

Identification of lymphatic endothelium in cranial arachnoid granulation-like dural gap

The dynamics of cerebrospinal fluid (CSF) are essential for maintaining homeostasis in the central nervous system. Despite insufficiently detailed descriptions of their structural and molecular properties for a century, cranial arachnoid granulations (CAGs) on meninges have been thought to participate in draining CSF from the subarachnoid space into the dural sinuses. However, recent studies have demonstrated the existence of other types of CSF drainage systems, such as lymphatic vessels adjacent to dural sinus and paravascular space in the brain so-called glymphatic system. Therefore, the role of CAGs in CSF drainage has become dubious. To better understand CAG function, we analyzed the ultrastructure and molecular identity of CAG-like structure on meninges adjacent to the superior sagittal sinus of pigs. Transmission electron microscopy analysis revealed that this structure has a reticular conglomerate consisting of endothelial cells that resembles lymphatic linings. Furthermore, immunohistochemistry and immunoelectron microscopy showed that they express molecules specific to lymphatic endothelial cell. We coined a name 'CAG-like dural gap (CAG-LDG)' to this structure and discussed the physiological relevance in terms of CSF drainage.

PKD1-Associated Arachnoid Cysts in Autosomal Dominant Polycystic Kidney Disease

OBJECTIVES

the prevalence of intracranial aneurysms and arachnoid cysts is higher in patients with autosomal dominant polycystic kidney disease (ADPKD) than in the general population. A genotype correlation was reported for intracranial aneurysms, but it is unclear for arachnoid cysts. Therefore, the genotype correlation with intracranial aneurysms and arachnoid cysts was investigated in ADPKD.

MATERIALS AND METHODS

intracranial aneurysms and arachnoid cysts were screened by magnetic resonance imaging (MRI), and PKD genotypes were examined using next-generation sequencing for 169 patients with ADPKD.

RESULTS

PKD1-, PKD2- and no-mutation were identified in 137, 24 and 8 patients, respectively. Intracranial aneurysms and arachnoid cysts were found in 34 and 25 patients, respectively, with no significant difference in frequency. Genotype, sex, estimated glomerular filtration rate and age at ADPKD diagnosis significantly affected the age at brain MRI. The proportional hazard risk analyzed using the age at brain MRI adjusted by these four variables was 5.0-times higher in the PKD1 group than in the PKD2 group for arachnoid cysts (P = 0.0357), but it was not different for intracranial aneurysms (P = 0.1605). Arachnoid cysts were diagnosed earlier in the PKD1 group than in the PKD2 group (54.8 vs 67.7 years, P = 0.0231), but no difference was found for intracranial aneurysms (P = 0.4738) by Kaplan-Meier analysis.

CONCLUSIONS

this study demonstrated the correlation between arachnoid cysts and PKD1 mutation. The reported association of arachnoid cysts with advanced renal disease may be due to the common correlation of these factors with PKD1 mutation.

Cystoventricular Drainage of Intracranial Arachnoid Cysts in Adults

BACKGROUND

Intracranial arachnoid cysts (ACs) are generally benign fluid-filled cysts with a prevalence of 0.5%-2.7%. They can be treated through craniotomy with cyst removal, endoscopic fenestration, or cystoperitoneal or ventriculoperitoneal shunting. However, the outcome of these treatments has not been completely satisfactory. Cystoventricular shunting was described as an alternative method for the treatment of intracranial ACs in children in 2003. In the present report, we have described the outcomes of cystoventricular shunting in adults with symptomatic intracranial ACs.

METHODS

A total of 24 patients with symptomatic ACs underwent cystoventricular drainage from 2012 to 2019. The most common symptom preoperatively was headache, followed by dysphasia, motor weakness, memory loss, seizures, and balance disturbances. After radiological evaluation, a ventricular catheter was placed in the AC and another in one of the lateral ventricles and connected extracranially after subgaleal tunneling using a straight metal connector.

RESULTS

At 3-6 months of postoperative follow-up, 21% of patients were asymptomatic and 42% showed improvement in clinical symptoms. No patient had experienced impairment or progression of symptoms postoperatively. Three patients had required revision of the catheters and one patient had developed a postoperative superficial skin infection without signs of deeper infection.

CONCLUSIONS

Cystoventricular drainage seems to be an effective, reliable, and safe procedure to treat intracranial ACs when fenestration to the basal cisterns is not possible.

Space-occupying brain lesions, trauma-related tau astrogliopathy, and ARTAG: a report of two cases and a literature review

Astrocytes with intracellular accumulations of misfolded phosphorylated tau protein have been observed in advanced-stage chronic traumatic encephalopathy (CTE) and in other neurodegenerative conditions. There is a growing awareness that astrocytic tau inclusions are also relatively common in the brains of persons over 70 years of age-affecting approximately one-third of autopsied individuals. The pathologic hallmarks of aging-related tau astrogliopathy (ARTAG) include phosphorylated tau protein within thorn-shaped astrocytes (TSA) in subpial, subependymal, perivascular, and white matter regions, whereas granular-fuzzy astrocytes are often seen in gray matter. CTE and ARTAG share molecular and histopathologic characteristics, suggesting that trauma-related mechanism(s) may predispose to the development of tau astrogliopathy. There are presently few experimental systems to study the pathobiology of astrocytic-tau aggregation, but human studies have made recent progress. For example, leucotomy (also referred to as lobotomy) is associated with a localized ARTAG-like neuropathology decades after the surgical brain injury, suggesting that chronic brain injury of any type may predispose to later life ARTAG. To examine this idea in a different context, we report clinical and pathologic features of two middle-aged men who came to autopsy with large (> 6 cm in greatest dimension) arachnoid cysts that had physically displaced and injured the subjects' left temporal lobes through chronic mechanical stress. Despite the similarity of the size and location of the arachnoid cysts, these individuals had dissimilar neurologic outcomes and neuropathologic findings. We review the evidence for ARTAG in response to brain injury, and discuss how the location and molecular properties of astroglial tau inclusions might alter the physiology of resident astrocytes. These cases and literature review point toward possible mechanism(s) of tau aggregation in astrocytes in response to chronic brain trauma.

Ruptured intra-cranial arachnoid cysts: a case series from a single UK institution

INTRODUCTION

Intracranial arachnoid cysts are a common incidental finding; however presentation with cyst rupture is a recognised complication. Patients are advised to avoid contact sports to reduce the risk of cyst rupture but the risk of rupture is not currently known. The aim of this study is to describe a single institution's experience of managing ruptured intra-cranial arachnoid cysts.

METHOD

A retrospective case note review of all patients admitted to a single institution with a ruptured intra-cranial arachnoid cyst between 2005 and 2016 (inclusive). Medical records were reviewed for demographics, history of trauma, surgical treatment and radiological evidence of cyst rupture.

RESULTS

Fourteen patients were identified for inclusion with an average age of 23.4 years (range 7-57) and 10 (71%) were male. Nine patients (64%) had a documented history of head trauma. Eleven patients (78.6%) required neurosurgical intervention which included hygroma/haematoma evacuation only (n = 5), haematoma evacuation with cyst fenestration (n = 4) and cyst fenestration/shunting only (n = 2). Twelve patients (85%) experienced full recovery and the remaining two had persisting headaches or neurological symptoms.

DISCUSSION

Cyst rupture remains an uncommon cause for presentation with arachnoid cysts. However the majority are associated with head trauma and thus current advice to avoid contact sports seems justified.

Arachnoid cysts: using prenatal imaging and need for pediatric neurosurgical intervention to better understand their natural history and prognosis

OBJECTIVES

Intracranial arachnoid cysts are commonly characterized as congenital. Evidence to support a congenital origin is scant and documented evolution during infancy also calls into question the genesis of these lesions. To improve our understanding of the natural history and the clinical significance of arachnoid cysts on prenatal ultrasound, we conducted a study to describe the fate of these cysts after initial diagnosis.

METHODS

We conducted a retrospective descriptive review of all prenatal ultrasounds with reported intracranial arachnoid cysts at a tertiary care center from 2010 to 2016 and cohort study comparing patients with additional ultrasound abnormalities to those with an isolated finding of arachnoid cyst. Data collected included gestational age at cyst diagnosis, cyst evolution on follow-up imaging, cyst size and cyst location, postnatal imaging and neurosurgical consultation and intervention. Statistical analysis including Chi-square and Fisher's exact tests and univariate logistic regressions were performed using Stata v. 13 (StataCorp 2013. Stata Statistical Software: Release 13. College Station, TX: StataCorp LP). Confidence intervals were reported at 95% and a p-value < .05 was considered significant.

RESULTS

A total of 33,621 anatomical ultrasound scans were performed from 2010 to 2016. Seventy patients (0.2%) had prenatal findings of arachnoid cyst, of which the mean gestational age was 21.46 weeks. Ventriculomegaly was observed in one patient (1.4%) at the time of diagnosis and other abnormalities were found in twelve patients (17%). Complete sonographic follow-up prior to delivery was obtained in 53 (75.7%) patients with 5(9.4%) progression, 5(9.4%) regression, and 43(81.1%) no longer visualized. Forty-three cysts (81.1%) were no longer visualized on follow-up imaging, all of which were interhemispheric in location. All of the cysts that progressed in size on prenatal ultrasounds were > 2 cm in size on initial diagnosis. Cyst fenestration was performed in two patients (2.9%) that had arachnoid cysts measuring at least 3 cm in each dimension on prenatal imaging, one at eight months and one at six months of age. Patients with and without additional sonographic abnormalities had similar rates of AMA (23.1% vs 26.3%, p = .56), nulliparity (61.5% vs 70.2%, p = .38), obesity (0.0% vs 12.3%, p = .221), major medical comorbidities (38.5% vs 33.3%, p = .48) and pregnancy achieved via Assisted Reproductive Technology (38.5% vs 24.6%, p = .25), respectively. Patients with additional sonographic abnormalities were significantly more likely to have prenatal Magnetic Resonance Imaging (OR: 8.28, CI: 1.84-40.4, p = .07), prenatal neurosurgery consultation (OR: 8.25, CI: 1.23-69.05, p = .04) and invasive diagnostic genetic testing (OR: 11.25, CI: 2.33-64.35, p = .003).

CONCLUSIONS

Arachnoid cysts are infrequently found on prenatal screening. Size greater than 2 cm on second trimester ultrasound and location outside of the interhemispheric fissure may indicate the need for further evaluation and eventual fenestration. Prenatally diagnosed arachnoid cysts are not typically associated with other anatomic or genetic abnormalities, although the presence of additional abnormalities usually leads to more intensive prenatal and postnatal investigations.

Glimpse into Pathophysiology of Sellar Arachnoid Cysts

BACKGROUND

Sellar arachnoid cysts are a rare occurrence but may impinge on vital parasellar anatomy and thus are often symptomatic. The etiology of sellar arachnoid cysts is contentious, fueled by heterogeneity in cyst wall structure and contents between cases. The "ball-valve" mechanism is 1 of 2 predominant theories describing their formation, which contends that an aperture in the diaphragm allows cerebrospinal fluid to enter the cyst, propelled by pulsatile flow, but its egress is obscured by the pituitary during the ebb of the pressure wave.

CASE DESCRIPTION

Here we present a case of a 51-year-old female with a symptomatic sellar arachnoid cyst. She underwent an endoscopic transsphenoidal fenestration which alleviated her symptoms.

CONCLUSIONS

Intraoperative video evidence during arachnoid cyst fenestration supports the "ball-valve" theory of sellar arachnoid cyst development.

Does subjective improvement in adults with intracranial arachnoid cysts justify surgical treatment?

OBJECTIVE

Subjective improvement of patients who have undergone surgery for intracranial arachnoid cysts has justified surgical treatment. The current study aimed to evaluate the outcome of surgical treatment for arachnoid cysts using standardized interviews and assessments of neuropsychological function and balance. The relationship between arachnoid cyst location, postoperative improvement, and arachnoid cyst volume was also examined.

METHODS

The authors performed a prospective, population-based study. One hundred nine patients underwent neurological, neuropsychological, and physiotherapeutic examinations. The arachnoid cysts were considered symptomatic in 75 patients, 53 of whom agreed to undergo surgery. In 32 patients, results of the differential diagnosis revealed that the symptoms were due to a different underlying condition and were unrelated to an arachnoid cyst. Neuropsychological testing included target reaction time, Grooved Pegboard, Rey Auditory Verbal Learning, Rey Osterrieth complex figure, and Stroop tests. Balance tests included the extended Falls Efficacy Scale, Romberg, and sharpened Romberg with open and closed eyes. The tests were repeated 5 months postoperatively. Cyst volume was pre- and postoperatively measured using OsiriX software.

RESULTS

Patients who underwent surgery did not have results on balance and neuropsychological tests that were different from patients who declined or had symptoms unrelated to the arachnoid cyst. Patients with a temporal arachnoid cyst performed within the normal range on the neuropsychological tests. Seventy-seven percent of the patients who underwent surgery reported improvement, yet there were no differences in test results before and after surgery. Arachnoid cysts in the temporal region and posterior fossa did not influence the preoperative results of neuropsychological and motor tests. The arachnoid cyst volume decreased postoperatively (p < 0.0001), but there was no relationship between volume reduction and clinical improvement.

CONCLUSIONS

The results of this study speak against objectively verifiable improvement following surgical treatment in adults with intracranial arachnoid cysts.

Prevalence and symptoms of intracranial arachnoid cysts: a population-based study

To investigate the prevalence of intracranial arachnoid cysts in a large population-based sample. We also aimed to assess the association between arachnoid cysts and cognitive impairment, depression, epilepsy, headache, dizziness, previous head trauma, hip fractures, and mortality. A population-based cohort and nested case-control study. The sample comprised representative populations (n = 1235) aged ≥ 70 years. All participants underwent baseline neuropsychiatric examinations, including computed tomography (CT) of the brain, between 1986 and 2000. All CT scans were examined for arachnoid cysts. Headache, dizziness, history of head trauma, dementia, depression, epilepsy, and hip fracture were assessed using data from clinical examinations, interviews and the Swedish hospital discharge register. Cognition was assessed using the Mini-Mental Status Examination, and depressive symptoms using the Montgomery-Åsberg Depression Rating Scale. Date of death was obtained from the National Swedish Death Registry. The prevalence of arachnoid cysts was 2.3 % (n = 29), with no significant difference between men and women. Probands with and without cysts had the same frequency of headache, dizziness, previous head trauma, cognitive impairment, and depressive symptoms. Furthermore, there were no differences regarding the prevalence of dementia, depression, epilepsy, or previous hip fracture. Arachnoid cysts were not associated with increased mortality. Arachnoid cysts are common incidental finding, with the same rate in men and women, and are probably asymptomatic. The lack of relation with symptoms like headache, dizziness and cognitive impairment suggest caution in ascribing symptoms to incidentally discovered arachnoid cysts and a restrictive attitude to treatment.

Intracranial Intra-arachnoid Diverticula and Cyst-like Abnormalities of the Brain

Primary intracranial cystic or cyst-like lesions include intra-arachnoid, epidermoid, dermoid, and choroid plexus cysts. Differentiation of these cystic lesions can usually be accomplished by imaging studies alone; however, some cysts are similar in appearance and require histopathology for definitive diagnosis. Clinical signs often reflect the location of the cysts within the intracranial cavity rather than the type of cyst. If clinical signs are significant and progressive, surgical removal is warranted and may be successful, although cystic contents could be harmful if allowed to contact surrounding brain parenchyma or meninges.