Do arachnoid cysts grow? A retrospective CT volumetric study

The volumes of intracranial arachnoid cysts were measured in 136 CT scans of 86 patients. Absolute and relative cyst size was calculated. Left hemisphere and middle cranial fossa location prevailed. A slight negative correlation of relative cyst size with age (r = -0.21, NS) disappeared when analysis was restricted to the adult age group (greater than or equal to 20 years). After the sample was divided into two groups according to relative cyst size (cysts less than mean volume vs cysts greater than mean volume), small AC showed no correlation with age, while large AC correlated positively with age (r = 0.79, P less than 0.05). A subgroup of large AC appears to expand with time, while the majority of small AC remain unchanged.

Thoracic intradural arachnoid cyst: possible pitfalls with myelo-CT and MR

A thoracic intradural arachnoid cyst presenting as an intradural extramedullary mass highly suggestive of psammoma on myelogram and myelo-CT is reported in a 34-year-old female. High densities of the cyst were related to collection of contrast media within the cyst. However MR examination of the thoracic spinal cord including sagittal T1 (without and with contrast) and T2 studies failed to demonstrate the mass. Lack of MR changes were related on one hand to the small size of the cyst and to the absence of mass effect on the spinal cord, and on the other hand to a CSF-like signal of the contents of the cyst. Only combination of myelography, myelo-CT and MR allows precise diagnosis of small intradural arachnoid cyst; however MR is the method of choice for evaluation of large intradural subarachnoid cysts.

Rare causes of hemifacial spasm. Report of two cases

Two patients are presented whose sole symptom was hemifacial spasm. Cerebellar arachnoid cyst was diagnosed in one patient who was treated effectively by removal of the cyst and decompression of the facial nerve. The second patient had an AVM of the posterior fossa. Surgery was withheld in this case.

Cauda equina syndrome associated with multiple lumbar arachnoid cysts in ankylosing spondylitis: improvement following surgical therapy

A case of cauda equina syndrome with multiple lumbar arachnoid cysts complicating ankylosing spondylitis (AS) is described. The value of computerised tomography (CT) and magnetic resonance imaging (MRI) as a non-invasive means of establishing the diagnosis is emphasised. In contrast to previously reported cases the patient showed neurological improvement following surgical therapy. Surgery may be indicated in some patients, particularly when there is nerve root compression by the arachnoid cysts and when the patient is seen early before irreversible damage to the cauda equina has occurred.

Unusual intra- and extracranial arteriovenous communication--case report

The authors report an unusual case of arteriovenous communication between extracranial and intracranial vessels, accompanied by incidentally detected bilateral arachnoid cysts of the middle cranial fossa. A 52-year-old male was admitted with a sudden onset of headache, vomiting, and conjunctival hyperemia of the right eye followed by progressive chemosis and proptosis. He had undergone a craniotomy for hypertensive right putaminal hemorrhage 4 months previously. Angiography showed the main feeding artery to be the superficial temporal artery and the draining veins to be the superficial Sylvian veins and the basal vein of Rosenthal. Partial obstruction of the right cavernous sinus was also shown. At surgery, granulation tissue continued to the dura mater through the skull aperture of previous craniotomy and adhered to the underlying damaged cerebrum. The extremely unusual nature of the communication, the operative findings, and the atypical fistulous figures suggested that communication had occurred postoperatively via newly generated vessels in granulation tissue.

Arachnoid cysts of the middle cranial fossa: a clinical, radiological and follow-up study

Twenty-seven patients with CT-scan-diagnosed arachnoid cysts in the middle cranial fossa were studied. Five (18%) presented with progressive symptoms related to raised intracranial pressure which had developed after minor trauma and secondary bleeding, 12 (44%) presented with non-progressive symptoms, and 10 (37%) exhibited neurological syndromes not referable to the cyst. Among those with non-progressive symptoms, epilepsy was the most common presentation (67%). More than 60% of the cysts were small and limited to the anterior temporal region or to the Sylvian fissure, the remaining cysts involved both the anterior temporal region and the Sylvian fissure, and expanded to the adjacent fronto-temporal or fronto-parietal regions. The volume measurements of the brain tissue performed on CT scan revealed that between the volume of the two hemispheres there was no significant difference suggesting any evidence of agenesis or hypoplasia of the affected temporal lobe.

[Radioisotope cisternography in the diagnosis of subarachnoid cysts]

Two cases of subarachnoid cysts are presented. Radioisotope cisternography proved successful in the diagnosis of this disorder. CT-scan and surgery confirmed diagnostic value of the radioisotope cisternography. It may be useful in case of inability to use CT-scan, being safe and valuable.

Cranial computed tomography and magnetic resonance imaging in autosomal dominant polycystic kidney disease

High resolution computed tomography or magnetic resonance imaging of the head with 3-mm sections through the circle of Willis was obtained in 96 patients with autosomal dominant polycystic kidney disease. These scans are well suited for the noninvasive, presymptomatic diagnosis of intracranial aneurysms at high risk of rupture, since the risk of rupture of unruptured aneurysms is heavily dependent on their size, and aneurysms equal to or larger than 6 mm in diameter are not likely to escape detection by these techniques. No definite aneurysm was observed in any of the 96 patients. Small areas (2-4 mm) of contrast enhancement or signal void were detected in 11 patients. These areas are possibly due to vascular tortuosity, but the studies were considered to be indeterminate because a small aneurysm could not be ruled out. Cerebral angiography in two of these 11 patients was normal. Arachnoid cysts were observed more frequently in the patients with polycystic kidney disease than in a control group of patients matched by gender, age, and type and date of examination.

Arachnoid cyst with rupture into the subdural space

Arachnoid cysts which develop in relation to the cerebral hemispheres are usually found in the middle cranial fossa. These cysts are usually asymptomatic but can produce symptoms if there is haemorrhage into the cyst or the development of an associated subdural hematoma. Recent publications have emphasised the association of arachnoid cysts of the middle fossa with subdural haematomas. This report describes a case of an asymptomatic arachnoid cyst which ruptured into the subdural space. This event was followed by the development of symptoms despite the lack of haemorrhage.

Ankylosing spondylitis: cauda equina syndrome with multiple spinal arachnoid cysts

✓ A case of ankylosing spondylitis in a patient with a cauda equina syndrome is reported. A lumbar myelogram revealed erosions of the bones of the neural canal with enclosed multiple intraspinal cysts.