De novo suprasellar arachnoid cyst: case report and review of the literature

Postnatal Posterior Fossa Arachnoid Cyst: A Developmental Etiology to Be Considered

Intracranial arachnoid cyst is the most common cystic congenital anomaly in the brain. In this study, we discuss a pregnancy that had serial fetal ultrasound scans throughout the pregnancy and a fetal anomaly scan at 24 weeks of gestation that was normal. The child was born healthy with normal development, but 12 months onward the head began to enlarge. The magnetic resonance imaging of the brain showed a large posterior fossa arachnoid cyst with hydrocephalus. We discuss the postulation to explain this pathogenesis of the cyst. This case highlights that not all symptomatic arachnoid cysts are congenital despite the manifestation being as early as infancy.

Formation of de Novo Symptomatic Premedullary Arachnoid Cyst in Adult

BACKGROUND

Intracranial de novo arachnoid cysts in adults are rare, suggesting the involvement of head trauma and inflammatory diseases. We report a symptomatic adult case of nontraumatic de novo arachnoid cyst on the ventral medulla oblongata.

CASE DESCRIPTION

A 56-year-old man came to our hospital complaining of dysphagia and writing difficult since 3 months ago. There was no history of head injury or inflammatory disease. A 25-mm cystic lesion was found on the ventral side of the medulla oblongata on brain magnetic resonance imaging, and the lower cranial nerve and medulla oblongata were highly compressed. The lesion did not exist on magnetic resonance imaging performed 9 years ago. Capsular resection was performed, and the histologic diagnosis was a typical arachnoid cyst. After the operation, all neurologic symptoms disappeared and no recurrence has been observed after 6 months.

CONCLUSIONS

The pathophysiology of nontraumatic de novo arachnoid cysts has many unknown features, and it appears necessary to accumulate further case reports.

Surgically Treated de Novo Cervicomedullary Arachnoid Cyst in Symptomatic Adult Patient

BACKGROUND

Arachnoid cysts are a relatively common finding in adult patients, especially with the advent of advanced imaging techniques. The overall incidence ranges from 1%-2%, and the majority are clinically silent. Arachnoid cysts are postulated to arise by congenital anomalies or trauma. De novo formation of arachnoid cysts has been reported but is exceptionally rare and mostly found in the pediatric population after head trauma. There have only been 2 reported cases of symptomatic de novo arachnoid cyst formation in adult patients to date, both with histories of head trauma.

CASE DESCRIPTION

We present a case of a 71-year-old male patient with progressive vertigo who had previous brain magnetic resonance imaging studies without abnormalities. Another MRI was performed 3 years from the last study that showed interval development of a large cystic lesion compressing the right cervicomedullary junction, as well as radiologic evidence of neurosarcoidosis. Intraoperative findings showed a cystic mass with clear, gelatinous fluid. The cyst was drained, and the walls were resected and sent to pathology. Histopathologic testing confirmed the lesion was an arachnoid cyst. The patient's vertiginous symptoms improved after surgery.

CONCLUSIONS

This case represents the first incidence of a pathology-proven, nontraumatic de novo arachnoid cyst.

Huge Frontal-Temporal Lobe Arachnoid Cyst Presenting as an Weariness Migraine

To the authors' knowledge, most of intracranial arachnoid cyst located in middle cranial fossa and lateral fissure cistern. So, huge frontal-temporal lobe arachnoid cyst is rare. Symptoms of arachnoid cyst may be atypical, including headache, nausea, vomiting, epilepsy, poor memory, and so on. Of course, migraine related to weariness is a rare benign headache disorder. The authors reported a patient presenting with weariness migraine associated with large frontal-temporal lobe arachnoid cyst.

[«De novo» development of a suprasellar arachnoid cyst]

Intracranial arachnoid cysts are fluid-filled cavities that arise within the cranial arachnoid, representing approximately 1%-2% of all intracranial lesions among the paediatric population. We present the case of a 2-year-old boy who presented with instability and episodes of ocular deviation. A computed tomography scan (CT scan) and magnetic resonance imaging (MRI) of the brain revealed a suprasellar cyst and obstructive hydrocephalus. At birth a transfontanellar ultrasound was normal. The cyst underwent endoscopic fenestration with complete remission of symptoms. In the review of the literature, we found only 6 previous cases of an intracranial arachnoid cyst whose origin was not clearly congenital or traumatic, and ours is the second case of a suprasellar arachnoid cyst to arise de novo. The clinical features, imaging characteristics and treatment of the previously reported cases are discussed.

Diverse arachnoid cyst morphology indicates different pathophysiological origins

BACKGROUND

There are few, limited, and to some extent contradictory, reports on the cellular and subcellular morphology of arachnoid cysts. In the literature cyst membranes are described as similar to, or as vastly different from, normal arachnoid membranes.

METHODS

This paper reports electron microscopic analyses of symptomatic cysts from 24 patients (12 males and 12 females; age 10-79), that underwent fenestration surgery. Fourteen cysts were located in the middle cranial fossa (temporal), one in the interpeduncular cistern, five in the posterior fossa, and four were overlying the frontal cortex.

RESULTS

Microscopic findings confirmed the diverse nature of this clinical condition. Twelve cyst walls resembled normal arachnoid, four had a conspicuous core of dense fibrous tissue with a simple epithelial lining, and the remaining aberrant cysts exhibited non-arachnoid luminal epithelia with plentiful microvilli and/or cilia, and also nervous tissue components in the wall. The possible identity and origin of various cyst types are discussed. We hypothesize that cysts are formed mostly at an early stage of embryonic development, as a teratological event.

CONCLUSIONS

Cysts with various epithelial linings and extracellular components most likely have different barrier properties and fluid turnover characteristics. Further studies are needed to elucidate relations between cyst morphology, fluid composition, pathogenesis, and clinical behaviour including growth rate and relapse tendency.