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Neurology India
Medknow Publications on behalf of the Neurological Society of India
ISSN: 0028-3886 EISSN: 1998-4022
Vol. 58, Num. 2, 2010, pp. 312-315

Neurology India, Vol. 58, No. 2, March-April, 2010, pp. 312-315

Case Report

Two cases of arachnoid cyst complicated by spontaneous intracystic hemorrhage

Department of Neurosurgery, Bakırköy Hospital of Psychiatric and Neurological Diseases, and
1 Department of Neurosurgery, Bakırköy Dr. Sadi Konuk State Hospital, Bakırkoy-Istanbul-Turkey

Correspondence Address: , Atakoy 2.kisim L29 blok D:2, Bakirkoy-Istanbul, Turkey,

Date of Acceptance: 30-Nov-2009

Code Number: ni10079

PMID: 20508359

DOI: 10.4103/0028-3886.63795


Arachnoid cysts are developmental anomalies which are usually asymptomatic. Intracystic hemorrhage after trauma is a well known complication; however, spontaneous intracystic hemorrhage is rare. This report presents two rare cases of arachnoid cyst complicated by spontaneous intracystic hemorrhage. The first patient was admitted following transient loss of consciousness and speech disturbance, and a subacute subdural hematoma at the left temporal region was diagnosed. The second patient presented with severe headache of four days duration and a subdural hematoma at the left temporoparietal region was diagnosed. In both the patients, both on radiological examination and during surgical intervention, hematomas were found to be intracystic.

Keywords: Arachnoid cyst, intracystic hemorrhage, spontaneous subdural hematoma in arachnoid cyst


Arachnoid cysts are believed to be congenital fluid-filled cavities circumscribed by arachnoidal membrane that have settled in the cisternae and major cerebral fissures. It is estimated that 1% of non-traumatic intracranial mass lesions are arachnoid cysts. [1] Intracystic fluid resembles cerebrospinal fluid (CSF). A sylvian cisterna in the middle cranial fossa is the most common site for arachnoid cyst development. [2] They are usually asymptomatic and diagnosed incidentally on cranial radiological work-up for other reasons or in post mortem studies. [3] When symptomatic, they usually present with symptoms of increased intracranial pressure. On the other hand, symptomatic children may present with abnormal head shape, seizures and focal neurological deficits. There are reports of arachnoid cysts in the literature presenting with subdural, intracystic, or rarely extradural hematoma after trauma. [4],[5],[6],[7],[8],[9],[10],[11] This report presents radiological and clinical features of two patients with arachnoid cyst, complicated by spontaneous intracystic hemorrhage, a rare complication.

Case Reports

Case 1

A 57-year-old male patient was admitted for headache, impaired speech and transient loss of consciousness. His medical and family histories were unremarkable. The neurological examination was normal except for expressive aphasia. The computerized cranial tomography (CT) revealed a left temporal hyperdense lesion. Magnetic resonance (MR) imaging demonstrated a lesion of 5 x 4 x 3 cm, which was iso-hyper-intense on T1-weighted images. The central part of the lesion was hypo intense on T2-weighted images, while the surrounding was hyperintense [Figure - 1]. Workup for coagulopathy was negative. A left temporal craniotomy was performed. On opening the dura, the hematoma was found to be under the arachnoidal membrane. The membrane was opened and the hematoma was evacuated. Additionally the arachnoid membrane was also excised. The macroscopic appearance during surgery was concordant with an arachnoid cyst, complicated by an intracystic hematoma. The patient′s clinical condition improved quickly after surgery. He was discharged on the third postoperative day in good condition.

Early postoperative radiological imaging and the follow-up cranial MRI performed a year after the operation [Figure - 2] demonstrated the arachnoid cyst in the left temporal region.

Case 2

A 19-year-old female patient presented with severe and continuous headache of four days duration. The neurological and physical examinations were normal. Her medical and family histories were unremarkable. There was no history of trauma. The cranial CT revealed a left temporoparietal lesion isodense to brain parenchyma. The lesion had a maximum width of 3 cm and the imaging findings were consistent with a subdural hematoma. MRI demonstrated a lesion on left temporoparietal region with a maximum width of 4 cm, causing a 2 cm cerebral shift to the right side. The lesion was hypointense on T1, hyper intense on T2 and isointense on FLAIR weighted images. There was no contrast enhancement and the features were consistent with a subacute subdural hematoma [Figure - 3]. Workup for coagulopathy was negative.

An immediate left temporoparietal craniotomy was performed and the hematoma was evacuated. The macroscopic appearance during surgery was consistent with an arachnoid cyst, complicated by an intracystic hematoma, which was characterized like a subdural hematoma. Postoperative radiological imaging showed that the hematoma was removed and the arachnoid cyst was present [Figure - 4]. Postoperatively the patient had a normal neurological examination and was dismissed on the fourth day.


Arachnoid cysts are congenital malformations resulting form CSF accumulation in between the laminae of the arachnoid membrane. [7],[12] They are usually found in the Sylvian fissure; however, parasellar region, cerebral convexity, interhemispheric fissure, quadrigeminal plate, cerebellopontine angle, vermian and retroclival area are also the regions where arachnoid cysts can develop. [2] Galassi has classified arachnoid cysts into three groups according to their size and relation with the Sylvian fissure. Type 1: Small and spindle shaped cysts which are localized in the anterior temporal pole. Enhanced CT cisternography usually reveals their connection with the subarachnoid space. Type 2: Cysts localized in the middle and proximal parts of the sylvian cisterna. The insula is uncovered. Type 3: Cysts covering the entire Sylvian fissure, leading to midline shift. They have minimal connection with the subarachnoid space. [13],[14]

Arachnoidal differentiation is completed at the fifteenth week of the gestation and arachnoid cysts may be the result of tears in the arachnoid during the formation of the subarachnoid cisternae resulting from the changes in the CSF flow, [15] or, they can be the result of entrapment of the CSF in a diverticulum. [2] Another hypothesis asserts that arachnoid cysts are formed during the separation of the arachnoid membrane from the dura mater. Trauma is another factor suspected to be the underlying pathogenesis of arachnoid cysts. [16] According to Naidich et al., arachnoid cysts are the result of pulsation of the CSF and the changes in the developing central nervous system, arachnoid and the pia. [17] The wall of the arachnoid cyst is covered with arachnoid membrane and includes lamellar and collagen connections. The membrane can contain veins and capillaries and the ependyma can have cuboidal epithelia. In most of the cases, the arachnoid duplicates itself at the borders of the cyst wall. They are usually formed of static fluid compartments; however, some can grow in time. These can have remnants of the choroid plexus, arachnoid granulations or the subdural neuroepithelium, leading to active CSF secretion. [2]

Arachnoid cysts demonstrate non-enhancing, well circumscribed, non-calcified, and extra-parenchymal cystic mass lesions on CT or MR. [18],[19] These techniques are also useful in cases of arachnoid cysts complicated by hemorrhage. Gradual density of the hemorrhage demonstrated in CT is the sign of chronicity of the hemorrhage. In the hyperacute stage T1-weighted MR images reveal hypointensity, while T2-weighted images demonstrate hyperintensity. In the acute stage, T1-weighted MR images demonstrate iso- or minimal hypointensity, whereas T2-weighted images demonstrate hyperintensity. In the subacute stage, both sequences demonstrate hyperintense lesions, and in the chronic stage, the peripheral part of the lesion is hypointense, while the central part is hyper intense. Hypointensity advances to the peripheral part of the lesion in time. [18],[19],[20],[21],[22] In our first patient, the T1-weighted slices demonstrated hyperintensity, while T2-weighted images demonstrated central hypointensity and peripheral hyperintensity. This was consistent with late phase acute intracystic hemorrhage. In the second patient the T1-weighted images demonstrated isointensity to brain parenchyma and T2 and FLAέR weighted images demonstrated hyperintensity. This was consistent with a phase of between acute and subacute hematoma. Arachnoid cyst complicated by subdural or intracystic hemorrhage is a rare entity. Robinson and Smith have reported that 2.43% of the arachnoid cysts in the middle cranial fossa can present with subdural hematoma or hygroma. [1],[11],[23] These cases are usually diagnosed after neurological impairment following moderate head injury. Cases of arachnoid cysts presenting with intracranial hematoma have also been reported. [4],[5],[7],[10],[24] The lower compliance of the cyst tissue compared to the normal brain or tears in the bridging veins may be the underlying factors. [8],[25],[26],[27] Probably this is the mechanism for the spontaneous hemorrhage in both our patients. But in both our patients, history of previous head trauma was absent. Spontaneous intracystic hemorrhages are extremely rare. There are four reports of arachnoid cysts complicated by spontaneous intracystic hemorrhage in the literature. [9],[22],[28],[29] We wish to highlight the point, although rare spontaneous intracystic hemorrhage into an arachnoid cyst can occur and one should consider this possibility in an appropriate clinical setting.


1.Robinson RG. Congenital cysts of the brain: arachnoid malformations. Prog Neurol Surg 1971;4:133-74.  Back to cited text no. 1    
2.Kanev PM. Arahnoid cysts. In: Winn HR, Youmans JR, editors. Neurological Surgery. Vol. 3. 5th ed. Philadelphia: WB Saunders; 2004. p. 3289-99.  Back to cited text no. 2    
3.Ide C, De Coene B, Gilliard C, Pollo C, Hoebeke M, Godfraind C, et al. Hemorrhagic arachnoid cyst with third nerve paresis: CT and MR findings. AJNR Am J Neuroradiol 1997;18:1407-10.   Back to cited text no. 3    
4.Boviatsis EJ, Maratheftis NL, Kouyialis AT, Sakas DE. Atypical presentation of an extradural hematoma on the grounds of a temporal arachnoid cyst. Clin Neurol Neurosurg 2003;105:225-8.   Back to cited text no. 4    
5.De K, Berry K, Denniston S. Hemorrhage into an arachnoid cyst: A serious complication of minor head trauma. Emerg Med J 2002;19:365-6.   Back to cited text no. 5    
6.Donaldson JW, Edwards-Brown M, Luerssen TG. Arachnoid cyst rupture with concurrent subdural hygroma. Pediatr Neurosurg 2000;32:137-9.  Back to cited text no. 6    
7.Ergόngφr MF, Dalgύη A, Nacar OA, Okay Φ, Gezici AR. Arachnoid cyst complicated with subdural hematoma: Case report and review of the literature. Turkish Neurosurg 2006;16:89-93.   Back to cited text no. 7    
8.Galassi E, Tognetti F, Pozzati E, Frank F. Extradural hematoma complicating middle fossa arachnoid cyst. Childs Nerv Syst 1986;2:306-8.   Back to cited text no. 8    
9.Hirose S, Shimada S, Yamaguchi N, Hosotani K, Kawano H, Kubota T. Ruptured aneurysm associated with arachnoid cyst: Intracystic hematoma without subarachnoid hemorrhage. Surg Neurol 1995;43:353-6.   Back to cited text no. 9    
10.Ildan F, Cetinalp E, Bagdatoglu H, Boyar B, Uzuneyuoglu Z. Arachnoid cyst with traumatic intracystic hemorrhage unassociated with subdural hematoma. Neurosurg Rev 1994;17:229-32.   Back to cited text no. 10    
11.Parsch CS, Krauss J, Hofmann E, Meixensberger J, Roosen K. Arachnoid cyst associated with subdural hematomas and hygromas: Analysis of 16 cases, long term follow-up and review of literature. Neurosurgery 1997;40:483-90.  Back to cited text no. 11    
12.Galassi E, Gaist G, Giuliani G, Pozzati E. Arachnoid cyst of middle cranial fossa: Experience with 77 cases treated surgically. Acta Neurochir suppl (Wien) 1988;42:201-4.   Back to cited text no. 12    
13.Galassi E, Tognetti F, Gaist G, Fagioli L, Frank F, Frank G. CT scan and metrizamide CT sisternography in arachnoid cyst of middle cranial fossa: Classification and pathophysiological aspect. Surg Neurol 1982;17:363-9.  Back to cited text no. 13    
14.Greenberg MS. Handbook of Neurosurgery. 6th ed. New York: Thieme Medical Publishers; 2006.  Back to cited text no. 14    
15.Lemire RJ, Loeser JD, Leech RW. Normal and abnormal development of the human nervous system. New York: Harper and Row; 1975.   Back to cited text no. 15    
16.Choi J, Kim D. Pathogenesis of arachnoid cyst: Congenital or traumatic? Pediatr Neurosurg 1998;29:260-6.  Back to cited text no. 16    
17.Naidich TP, McLone DG, Radkowski MA. έntracranial arachnoid cyts. Pediatr Neurosci 1985-1986;12:112-22.   Back to cited text no. 17    
18.Osborn AG, Blaser SI, Salzman KL, Provenzale J, Castillo M, Hedlund GL, et al. Diagnostic Imaging: Brain, 1st ed. Manitoba, Kanada: Amirsis; 2004.  Back to cited text no. 18    
19.Taveras JM, Pile-Spellman J. Neuroradiology. 3rd ed. Baltimore USA: William and Wilkins; 1996.  Back to cited text no. 19    
20.Demirci A. έntrakranyal kanamanύn MRG bulgularύ. In: Erden έ, editor. Kranyospinal Manyetik Rezonans. Ankara: Pozitif matbaacύlύk; 2003. p. 50-7.  Back to cited text no. 20    
21.έbarra R, Kesav PP. Role of MR imaging in the diagnosis of complicated arachnoid cyst. Pediatr Radiol 2000;30:329-31.  Back to cited text no. 21    
22.Iglesias A, Arias M, Meijide F, Brasa J. Arachnoid cyst complicated by intracystic hemorrhage and spontaneous subdural hematoma: Magnetic resonance findings. Radiologia 2006;48:245-8.   Back to cited text no. 22    
23.Smith RA, Smith WA. Arachnoid cyts of the middle fossa. Surg Neurol 1976;5:366-9.   Back to cited text no. 23    
24.Kawanishi A, Nakayama M, Kadota K. Heading injury precipitating subdural hematoma associated with arachnoid cysts- two case reports. Neurol Med Chir (Tokyo) 1999;39:2312-3.   Back to cited text no. 24    
25.Page A, Paxton RM, Mohan D. A reappraisal of the relationship between arachnoid cysts of the middle fossa and chronic subdural hematoma. J Neurol Neurosurg Psychiatry 1987;50:1001-7.  Back to cited text no. 25    
26.Rogers MA, Klug GL, Siu KH. Middle fossa arachnoid cysts in association with subdural haematomas: A review and recommendations for management. Br J Neurosurg 1990;4:497-502.   Back to cited text no. 26    
27.Ulmer S, Engellandt K, Stiller U, Nabavi A, Jansen O, Mehdorn MH. Case report and review of literature: Chronic subdural hemorrhage into a giant arachnoidal cyst (Galassi Classification Type III). J Comput Assist Tomogr 2002;26:647-53.  Back to cited text no. 27    
28.Ochi M, Morikawa M, Ogino A, Nagaoki K, Hayashi K. Supratentorial arachnoid cyst and associated subdural hematoma: Neuroradiologic studies. Eur Radiol 1996;6:640-4.  Back to cited text no. 28    
29.Sener RN. Arachnoid cysts associated with post-traumatic and spontaneous rupture into the subdural space. Comput Med Imaging Graph 1997;21:341-4.  Back to cited text no. 29    

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