|Year : 2019 | Volume
| Issue : 1 | Page : 28-29
Retrocerebellar arachnoid cyst of the posterior fossa presenting with headache
Department of Radiology, Holy Family Hospital, Thodupuzha, Kerala, India
|Date of Submission||04-Dec-2018|
|Date of Acceptance||23-Apr-2019|
|Date of Web Publication||20-Jun-2019|
Dr. Reddy Ravikanth
Department of Radiology, Holy Family Hospital, Thodupuzha - 685 605, Kerala
Source of Support: None, Conflict of Interest: None
Arachnoid cysts are benign, fluid-filled, cyst-liked malformations related to the arachnoid mater. Arachnoid cysts involving the posterior fossa are less common and exert local mass effect resulting in the symptoms and signs of cerebellar and brainstem dysfunction. Here, we present a case of a 14-year-old female with a retrocerebellar arachnoid cyst.
Keywords: Arachnoid cyst, episodic headache, gait disturbances, retrocerebellar
|How to cite this article:|
Ravikanth R. Retrocerebellar arachnoid cyst of the posterior fossa presenting with headache. BLDE Univ J Health Sci 2019;4:28-9
Arachnoid cysts are benign, fluid-filled, cyst-liked malformations related to the arachnoid mater. They can be formed everywhere of cerebrospinal axis with preference in the middle cranial fossa. Arachnoid cysts involving the posterior fossa are less common and are most often found in the cerebellopontine angle. Rarely, midline or unilateral posterior fossa arachnoid cysts exert local mass effect resulting in the symptoms and signs of cerebellar and brainstem dysfunction. Here, we present a case of a 14-year-old female with a retrocerebellar arachnoid cyst.
| Case Report|| |
A 14-year-old adolescent female presented with episodes of severe headache, vomiting, and gait disturbances for 3 months. On examination, her higher mental functions were normal. There was no evidence of papilledema or sensory-motor deficit. Cranial nerve examination was normal. Computed tomography (CT) imaging demonstrated a retrocerebellar posterior fossa arachnoid cyst of the left cerebellar convexity causing mass effect on the ipsilateral cerebellar hemisphere [Figure 1] with scalloping of the inner table of the occipital bone [Figure 2].
|Figure 1: Computed tomography brain image demonstrating a posterior fossa arachnoid cyst of the left cerebellar convexity exerting mass effect on the left cerebellar hemisphere|
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|Figure 2: Computed tomography brain image in bone window showing retrocerebellar arachnoid cyst causing scalloping of the inner table of the occipital bone|
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| Discussion|| |
Arachnoid cysts constitute 1% of all intracranial masses and are benign cysts with cerebrospinal fluid (CSF) as contents. Arachnoid cysts have an increased frequency in mucopolysaccharidoses. Arachnoid cysts appear in the subarachnoid space and are asymptomatic, and common locations include posterior fossa, middle fossa in the region of the temporal lobe and suprasellar region in the region of the third ventricle. Common presenting complaints include headache, visual disturbances, gait disturbances, and seizures. Rare manifestations include macrocephaly, focal neurologic deficits, cognitive decline, and cranial nerve palsies. In our patient, gait disturbances were likely due to the mass effect exerted by the arachnoid cyst on the left cerebellar hemisphere. Arachnoid cysts are incidentally detected on cross-sectional imaging during evaluation for seizures or headache. Patients with arachnoid cysts present with vague symptoms, and this often leads to delay in diagnosis.
On imaging, arachnoid cysts have an imperceptible wall, are well circumscribed, and may cause pressure effect like remodeling effect on the adjacent bone. Arachnoid cysts demonstrate communication with the subarachnoid space and pooling of contrast in the dependent region on CT cisternography. Arachnoid cysts follow CSF signal intensity on all magnetic resonance imaging (MRI) sequences which can help differentiate them from epidermoid cysts. Epidermoids show restriction on diffusion-weighted MRI sequence. No contrast enhancement is seen on CT/MRI. Differential diagnosis of arachnoid cysts includes mega cisterna magna, epidermoid cyst, and neuroenteric and neuroglial cysts. Large size of arachnoid cyst and features of raised intracranial pressure warrant for surgery. Shunting of cyst contents into the ventricle, cystoperitoneal shunt, fenestration into adjacent arachnoid spaces, and open craniotomy are the surgical options for cyst removal. Surgical treatment of arachnoid cyst can lead to complications such as pseudomeningocele, CSF leak, and subdural hygroma.
| Conclusion|| |
In patients presenting with headache or other neurological symptoms who have retrocerebellar space-occupying lesions, arachnoid cysts should be considered as a differential diagnosis which can be only followed up in asymptomatic cases because of their benign nature, whereas in symptomatic cases, surgical methods such as shunting of the cyst or fenestration into the adjacent subarachnoid spaces can be considered as the most effective treatment.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]