Case Report Unusual Volume Reduction of Galassi Grade III Arachnoid Cyst Following Head Trauma Marek Prokopienko1 Przemysław Kunert1 Andrzej Marchel1 1 Department of Neurosurgery, Medical University of Warsaw, Warsaw, Mazowieckie, Poland Address for correspondence Marek Prokopienko, MD, Department of Neurosurgery, Medical University of Warsaw, Banacha 1a, Warsaw, Mazowieckie 02-097, Poland (e-mail: mpro76@tlen.pl). J Neurol Surg A 2013;74(Suppl 1):e198–e202. Abstract Keywords ► arachnoid cyst ► sylvian fissure ► head trauma We report the case of a 36-year-old woman with a Sylvian fissure arachnoid cyst, which diminished after head trauma and minor hemorrhage into the cyst. We discuss the relationship between the cyst volume reduction and the head trauma to determine the main mechanism of this self-healing process. Introduction Middle cranial fossa and Sylvian fissure are the most frequent locations of intracranial arachnoid cysts. They were classified by Galassi using computed tomography (CT) and CT cisternography according to three basic types.1,2 In adulthood they are asymptomatic in the majority of cases. Headaches may be concern as a relatively frequent symptom. Less commonly, arachnoid cysts can occur with epileptic seizures. Rarely, they can result in chronic subdural or intracystic hematoma.3,4 Head trauma is the most common reason for the neuroimaging studies and the incidental diagnosis of the cyst. Even though intracranial hemorrhage in the case of the arachnoid cyst after head trauma is not uncommon, bleeding into the cyst is not frequent.5 Spontaneous disappearance of this pathology is very rare.6–8 We report a case in which a Sylvian fissure arachnoid cyst regressed after minor intracystal bleeding after a head trauma, and discuss the likely cause of the healing process. Case Report A 36-year-old woman was admitted after a car accident with a head trauma. At the time of admission, she was fully conscious and without any neurological deficit. A meticulous interview with the patient disclosed a prolonged history of headaches and epileptic seizures (episodes of ascending epigastric sensations, olfactory hallucinations, absence seizures). A CT scan of the brain at the time of admission showed received April 30, 2012 accepted after revision December 20, 2012 published online May 21, 2013 no posttraumatic lesions; however, a large right-sided Sylvian fissure arachnoid cyst was found. A bone scan revealed thinning of adjacent skull bone. Magnetic resonance imaging (MRI) confirmed the presence of the grade III Sylvian fissure cyst, according to Galassi classification.1 Electroencephalography revealed no abnormality. After 7 days, repeated MRI scans revealed insignificant subdural hygroma and a change of signal in the intracystic fluid. Minor hemorrhage into the cyst with rupture of cyst fluid to the subdural space was suspected. During the hospital stay, the patient was stable and no neurosurgical intervention was needed. Due to the history of previous epileptic seizures, an antiepileptic therapy was administered. After a few days the patient was discharged home without any neurological deficits. No consecutive epileptic seizures were noticed during the hospitalization or after the discharge. Shortly afterward, the antiepileptic therapy was discontinued based on the patient’s own demand. One month later, a follow-up MRI scan showed significant regression of the arachnoid cyst volume. The signal of intracystal fluid became less hypointensive in T1-weighted and more hyperintensive in T2-weighted images compared with cerebrospinal fluid outside the cyst. In addition, a slight contrast enhancement on the internal surface of the cyst appeared. The capsule of a discrete subdural hematoma, which was not present in the previous studies, was enhancing remarkably after contrast administration, but no remnant of hematoma was found outside the cyst (►Fig. 1). Fifteen months later, a control MRI study revealed further volume © 2013 Georg Thieme Verlag KG Stuttgart · New York DOI http://dx.doi.org/ 10.1055/s-0033-1342931. ISSN 2193-6315. This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited. e198 Prokopienko et al. Fig. 1 (A, B) Initial computed tomography examination a few hours after the head trauma. Posttraumatic changes (including subdural hematoma and bleeding into the cyst) are not seen. Thinning of the adjacent bone is visualized. (C, D) Magnetic resonance imaging (MRI) done on the second day after the trauma. The Galassi type III Sylvian fissure arachnoid cyst with slight mass effect is visualized. (E, F) MRI scans 1 week after the trauma: the insignificant subdural hygroma and detachment of the arachnoid from dura mater are seen. Intracystal fluid’s signal changed. Minor hemorrhage into the cyst suspicion was set. (G) MRI after 1 month. Significant volume reduction of the cyst. No mass effect. Intracystal fluid’s signal differs from cerebrospinal fluid. Discrete subdural hematoma capsule, not seen previously, is enhancing after contrast administration. (H) Control MRI study after 15 months. Further cyst’s volume reduction is visualized. reduction of the cyst. The patient remained asymptomatic with no epileptic seizures through 20 months of observation and remains asymptomatic. Discussion Arachnoid cysts in adulthood are diagnosed quite frequently during evaluation of many unrelated conditions. They are asymptomatic and remain unchanged in the majority of cases9,10; otherwise, they occur with headaches, epileptic seizures, or—rarely—with chronic subdural hematoma.5,11,12 Sudden deterioration can result if a cyst ruptures or bleeds into its cavity.11,13 The most symptomatogenic (up to 60%) are suprasellar cysts.14 Various theories have been proposed to explain the formation of these cysts: trapping of fluid by a ball-valve mechanism, secretion of fluid by ependymal cells, and fluid ingress due to an osmotic gradient.1,15,16 A diminishing of the cyst is less thoroughly discussed due to its infrequent occurrence. Only 29 case reports were published in the literature up to now (►Table 1). Most authors point out the possibility of a cyst wall rupture and spontaneous cystocisternostomy.7,17–25 Others speculate that the coexistence of subdural hematoma induces cyst regression.7,20,26 During the absorption of hematoma, the fluid in the cyst drains to the subdural space, after which the cyst becomes smaller and can gradually disappear. A change in the osmotic gradient is also recognized as a possible reason for the cyst’s volume reduction.9 Cysts diminishing after suppurative meningitis and use of antibiotics is extremely rare.27 Tracking successive examinations of our patient, we feel that the possible cause of the pathology’s decrease can be different. Minor intracystal hemorrhage could have resulted in a closing of the cyst’s valve mechanism such that the inflow to the cyst through the valve would have stopped. The fluid from the cyst flowed into the subdural space, from which it was absorbed. Subdural hygroma appeared a few days after the trauma and disappeared over a few months. Finally, the cyst significantly diminished. Presence of the valve was described by Yoshioka et al in 1998.27 Also Dodd et al22 and Seizeur et al28 considered the possibility of its presence. They also assumed that head trauma could create a tiny communication between the cyst and arachnoid space, resulting in reduction of the size of the cyst. A valve mechanism might have been present in all described cases. Different authors described similar process, but their point of interest was divergent. Although the surrounding brain lobes did not seem to be significantly compressed in the initial MRI scan, they almost filled the space that was occupied primarily by the arachnoid cyst. These observations led us to conclude that the brain compression was not so mild and that the cyst caused relatively extensive pressure on it. Even though the cyst was only mildly symptomatic, it caused a mass effect. The developmental rearrangement of the temporal lobe turned out to be less severe than it looked initially. Some authors postulate that, because of the possibility of enlargement and hemorrhage, most cysts should be treated by open surgery.2,29 Others consider that only enlarging and Journal of Neurological Surgery—Part A Vol. 74 Suppl. 1/2013 e199 This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited. Volume Reduction of Arachnoid Cyst Following Trauma Volume Reduction of Arachnoid Cyst Following Trauma Prokopienko et al. Table 1 Spontaneous regression of arachnoid cysts: review of literature Case Author/Year Age Location Trauma Time to resolution Degree of resolution 14 years Middle fossa – 2 years Complete 9 years Middle fossa þ 6 months Complete 3 Inoue/1987 20 7 years Middle fossa þ 18 months Almost complete 4 Takagi/1987 2 years CP Angle – 2 years Complete 5 Wester/1992 21 years Middle fossa – 3 years Complete 6 Weber/1991 25 13 years Middle fossa – 10 years Complete 7 Takizawa/1991 16 years Middle fossa þ 10 months Complete 8 Shiono/1993 13 years Middle fossa þ 9 months Complete 9 Mokri/1994 40 years Convexity – 11 years Almost complete 4 years Middle fossa þ 5 months Almost complete 8 1 Beltramello/1985 2 Yamanouchi/19866 10 Mori/1995 26 24 11 Rakier/1995 8 years Middle fossa þ 6 years Almost complete 12 Yoshioka/199827 2 months Middle fossa – 2 months Complete 13 McDonald/199721 24 years Middle fossa – 1 year Complete 14 Przybylo/1997 4 years Middle fossa – 7,5 years Complete 15 Yamauchi/1999 19 months Middle fossa – 7 years Complete 16 Pandey/200123 17 Dodd/2002 7 months Supracerebellar – Few days Complete 22 Prenatal Prepontine – 2 years Almost complete 7 10 years Middle fossa – 2 years Complete 1 year Convexity – 2 years Complete 15 years Suprasellar – 10 years Complete 18 Cokluk/2003 19 Cokluk/20037 20 19 Moon/2007 28 21 Seizeur/2007 23 years Middle fossa þ 16 months Almost complete 22 Bristol/2007 5 years Suprasellar þ 1 month Complete 23 Gelabert-Gonzalez/2008 31 years Middle fossa þ 13 years Complete 24 Jacob/2008 32 years Meckel’s cave – 7 months Complete 25 Russo/2008 43 years Posterior fossa – 2 months Almost complete 26 Bradley/2009 Infant Prepontine – 5 weeks Almost complete 27 Marlin/2010 Infant CB angle – 4 months Complete 28 Castro-Bouzas/2012 88 years Convexity þ 1 year Complete 29 Matsushita/2012 14 years Convexity þ 2 years Complete Abbreviation: CP= Cerebellopontine symptomatic cysts should be of concern.9,12,30 In particular, those cysts associated with the formation of subdural hematoma should at least be considered for an operative procedure.11 Some authors dispute the value of a “prophylactic” surgical treatment of incidentally discovered arachnoid cysts. Di Rocco emphasizes that the risk of possible complications, like postoperative subdural hygromas requiring surgical treatment, is at least twofold higher than reported for spontaneous or posttraumatic hygromas.31 Spontaneous diminishing is not documented in most of the cases of accidentally diagnosed arachnoid cysts, which is why Russo et al suggested a “wait and see” policy in asymptomatic and mildly symptomatic patients.32 Based on our policy, if the cyst had remained its primary size in the described patient, simultaneously with drug resistant epilepsy or increasing headaches, we would decide on surgical intervention. Journal of Neurological Surgery—Part A Vol. 74 Suppl. 1/2013 However, determining the optimal treatment method remains a challenge. Open surgery, cystoperitoneal shunting, and endoscopic cystocisternostomy have their limitations.29,30,33 Nevertheless, some authors choose straightforward operative treatment in cases of cysts accompanied by subdural hygroma or hematoma, but only if the effusion is space occupying and not small like in our case.34 Because the disappearance of arachnoid cysts after a head trauma is rare, we cannot draw far-reaching conclusions from our case. The closing of the cyst’s valve such that the flow was redirected to the subdural space was probably the main mechanism of the cyst’s disappearance in this case. Therefore we ask ourselves whether similar proceedings could be useful during operative procedure? It is possible that opening the external cyst’s wall and closing the valve mechanism (instead of widening it) could start the shrinking process? This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited. e200 Volume Reduction of Arachnoid Cyst Following Trauma Conflict of Interest None References 1 Galassi E, Tognetti F, Gaist G, Fagioli L, Frank F, Frank G. CT scan and metrizamide CT cisternography in arachnoid cysts of the middle cranial fossa: classification and pathophysiological aspects. Surg Neurol 1982;17:363–369 2 Galassi E, Gaist G, Giuliani G, Pozzati E. Arachnoid cysts of the middle cranial fossa: experience with 77 cases treated surgically. Acta Neurochir Suppl (Wien) 1988;42:201–204 3 Page AC, Mohan D, Paxton RM. Arachnoid cysts of the middle fossa predispose to subdural haematoma formation fact or fiction? Acta Neurochir Suppl (Wien) 1988;42:210–215 4 Wester K, Helland CA. How often do chronic extra-cerebral haematomas occur in patients with intracranial arachnoid cysts? J Neurol Neurosurg Psychiatry 2008;79:72–75 5 Parsch CS, Krauss J, Hofmann E, Meixensberger J, Roosen K. 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J Neurosurg 1991;74:230–235 30 Kang JK, Lee KS, Lee IW, et al. Shunt-independent surgical treatment of middle cranial fossa arachnoid cysts in children. Childs Nerv Syst 2000;16:111–116 31 Di Rocco C. Sylvian fissure arachnoid cysts: we do operate on them but should it be done? Childs Nerv Syst 2010;26:173–175 32 Russo N, Domenicucci M, Baccaglia MR, et al. Spontaneous reduction of intracranial arachnoid cyst: a complete review. Br J Neurosurg oct:22(5):626–9 33 Hopf NJ, Perneczky A. Endoscopic neurosurgery and endoscopeassisted microneurosurgery for the treatment of intracranial cysts. Neurosurgery 1998;43:1330–1336, discussion 1336–1337 34 Sprung C, Armbruster B, Koeppen D, Cabraja M. Arachnoid cysts of the middle cranial fossa accompanied by subdural effusions— experience with 60 consecutive cases. Acta Neurochir (Wien) 2011;153:75–84, discussion 84 35 Lucantoni C, Than KD, Wang AC, et al. Tarlov cysts: a controversial lesion of the sacral spine. Neurosurg Focus 2011;31:E14 36 Shao Z, Wang B, Wu Y, Zhang Z, Wu Q, Yang S. CT-guided percutaneous injection of fibrin glue for the therapy of symptomatic arachnoid cysts. AJNR Am J Neuroradiol 2011;32:1469–1473 37 Wang B, Shao Z, Wu H, et al. [Effect comparison of arachnoid cysts in sacral canal]. Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi 2010;24:206–210 Journal of Neurological Surgery—Part A Vol. 74 Suppl. 1/2013 This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited. Some authors35–39 suggest this procedure in similar pathology but in different location. Zhang et al used a fibrin glue to disconnect the communication between the subarachnoid space and a Tarlov cyst by closing the inlet of the valve. They achieved improvement in up to 80% of their cases.38 As it was noticed, fibrin glue resorption promotes fibrosis and may be a cause of fibroblast proliferation during the healing process.40,41 Because the formation mechanism in both entities (Tarlov cyst and Sylvian fissure’s arachnoid cysts) seems to be similar, the possibility of closing the valve in cranial arachnoid cysts using fibrin glue is worth consideration at least on the theoretical level. Prokopienko et al. Volume Reduction of Arachnoid Cyst Following Trauma Prokopienko et al. 38 Zhang T, Li Z, Gong W, et al. Percutaneous fibrin glue therapy for 40 Siedentop KH, Harris DM, Ham K, Sanchez B. Extended experi- meningeal cysts of the sacral spine with or without aspiration of the cerebrospinal fluid. J Neurosurg Spine 2007;7:145–150 39 Murphy KJ, Nussbaum DA, Schnupp S, Long D. Tarlov cysts: an overlooked clinical problem. Semin Musculoskelet Radiol 2011; 15:163–167 mental and preliminary surgical findings with autologous fibrin tissue adhesive made from patients own blood. Laryngoscope 1986;96:1062–1064 41 Siedentop KH, Harris DM, Sanchez B. Autologous fibrin tissue adhesive. Laryngoscope 1985;95(9 Pt 1):1074–1076 This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited. e202 Journal of Neurological Surgery—Part A Vol. 74 Suppl. 1/2013 Copyright of Journal of Neurological Surgery. Part A. Central European Neurosurgery is the property of Georg Thieme Verlag Stuttgart and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. Copyright of Journal of Neurological Surgery. Part A. Central European Neurosurgery is the property of Georg Thieme Verlag Stuttgart and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.