Bilateral cerebellopontine angle arachnoid cysts: case report

Arachnoid Cyst of the Cerebellopontine Angle: A Systematic Literature Review

OBJECTIVE

The role of surgical management of arachnoid cyst (AC) of the cerebellopontine angle (CPA) is uncertain. This topic has remained controversial with varying contradictory recommendations in the literature, which is limited to mostly case reports. We aimed to provide a comprehensive summary and analysis of symptoms, operative techniques, outcomes, and recurrence of all available surgical cases of AC of the CPA to date.

METHODS

A systematic literature search was performed in May 2022 querying several scientific databases. Inclusion criteria specified all studies and case reports of patients with AC located at the CPA for which any relevant surgical procedures were performed.

RESULTS

A total of 55 patients from the literature and 5 treated at our institution were included. Mean patient age was 29 years (range, 0.08-79 years), with nearly twice (1.7×) as many female as male patients (37 female, 22 male). Headaches (35%), hearing loss (30%), vertigo (22%), and ataxia (22%) were the most common presentations. Following surgery, 95% experienced symptom improvement, with complete resolution in 64%. Of patients with hearing loss, 44% reported a return to normal. The rate of mortality was 1.69%, and 10% of tumors recurred (mean follow-up 2.3 years [range, 0-15 years].

CONCLUSIONS

Symptomatic AC of the CPA is rare. It exhibits a proclivity for females and commonly manifests with headache, hearing loss, vertigo, and ataxia. While careful selection for surgical candidacy is needed and intervention should be reserved for patients with severe symptoms, surgical decompression is an effective tool for symptom alleviation and recovery.

Bilateral cerebellopontine arachnoid cyst: A rare entity

Bilateral cerebellopontine angle (CPA) arachnoid cysts (ACs) are very rare: only one case is reported in literature. Pathogenesis of those cysts is unknown; they are thought to be congenital. The presenting symptoms of CPA AC are frequently nonspecific or otological. The management of ACs of the CPA is controversial. We are reporting two cases of bilateral CPA AC with their pathophysiology and review of literature.

Arachnoid cyst of the cerebellopontine angle associated with gliosis of the eighth cranial nerve

The clinical syndrome produced by a cyst in the cerebellopontine angle (CPA) may closely mimic that of an acoustic neuroma, with sensorineural hearing loss, impaired corneal reflex, and cerebellar signs with increased intracranial pressure. Facial palsy is seldom reported. Gliosis of the eighth nerve is common but its association with CPA arachnoid cyst is very rare and not previously reported. We report a patient with a CPA arachnoid cyst associated with gliosis of the eighth cranial nerve. He presented with right peripheral facial palsy, and gliosis of the eighth nerve was diagnosed intraoperatively. CPA arachnoid cysts should be included in the differential diagnosis of peripheral facial palsy and the eighth cranial nerve should be examined during the resection and fenestration of the arachnoid cyst.

CEREBELLOPONTINE ANGLE CYST COMPRESSING THE VAGUS NERVE

OBJECTIVE

The cerebellopontine angle (CPA) is a rare location for an arachnoid cyst. We describe a patient with a CPA arachnoid cyst who presented with hoarseness (unilateral vocal cord paralysis) and dysphagia secondary to isolated compression of the vagus nerve. This rare presentation of a CPA arachnoid cyst has not been reported previously.

CLINICAL PRESENTATION

The patient described is a 50-year-old man who experienced a precipitous onset of hoarseness and dsyphagia. An otolaryngological evaluation revealed right-sided vocal cord paralysis. Brain magnetic resonance images displayed a cystic mass at the right CPA and anterior displacement of the vagus nerve.

INTERVENTION

The patient underwent retrosigmoidal craniectomy with cyst fenestration, which was well tolerated. Intraoperatively, Cranial Nerve X was found splayed over the cyst and was consequently decompressed.

CONCLUSION

Postoperatively, the patient's dysphagia completely resolved. However, the results of a laryngeal electromyocardiogram revealed minimal evidence of recovery in the affected vocal fold, and the patient continued to suffer from dysphonia. Although CPA arachnoid cysts are rare, they should be considered when a patient presents with an isolated cranial nerve palsy. Treatment options include cyst fenestration and cranial nerve decompression.

Congenital peripheral facial palsy associated with cerebellopontine angle arachnoid cyst

OBJECTS

A rare case of cerebellopontine angle arachnoid cyst leading to congenital peripheral facial palsy was presented.

CLINICAL PRESENTATION

A 1-year-old girl presented with peripheral facial paralysis since birth. Computed tomography and magnetic resonance imaging revealed left cerebellopontine angle arachnoid cyst causing moderate displacement of the brain stem.

INTERVENTION

Retrosigmoid suboccipital craniotomy was performed and microsurgical resection of the cyst wall and fenestration of the cyst to the basal cisterns were achieved.

CONCLUSIONS

Cerebellopontine angle arachnoid cyst should be considered as a potential cause of congenital peripheral facial palsy.

A different approach to cysts of the posterior fossa

Posterior fossa cysts are frequently identified on MR studies. This paper takes a different approach to analyzing these cysts based on the pathology of the cyst wall and the embryology of the hindbrain, choroid plexus, and meninges. The type of cyst depends on the histologic components of the cyst wall. Frequent types of posterior fossa cysts are arachnoid, Blake's pouch, and cysts associated with Dandy Walker malformation. All of these cysts may mimic the others in terms of position of the torcula, vermian abnormalities, and mass effect on the cerebellum and occipital bone. A clue to the nature of the cyst may be the position of the choroid plexus in the fourth ventricle; normal in arachnoid cyst, absent in Dandy Walker malformation, and displaced into the superior cyst wall in Blake's pouch. When the cyst wall histology is not known, it is suggested to use a descriptive term such as "retrocerebellar cyst".