Child's Nerv Syst (1991) 7:414-415
mGNS 9 Springer-Verlag 1991
Spontaneous regression of a temporal arachnoid cyst R. Weber 1, T. Voit 1, C. Lumenta 2, and H.-G. Lenard 1 1 Kinderklinik and 2 Neurochirurgische Klinik der Universitfit, Moorenstrasse 5, W-4000 Diisseldorf, Federal Republic of Germany Received September 18, 1990/Revised May 10, 1991
Abstract. Surgery is considered to be the standard therapy for arachnoid cysts (ACs). We report the case of a 13-year-old boy in w h o m a right temporal AC disappeared spontaneously over a period of 10 years. Bulging of the right temporal skull led to the detection of the cyst by c o m p u t e d t o m o g r a p h y (CT) scan at the age of 3 years. There were no other clinical symptoms. Subsequent CT scans showed spontaneous regression of the cyst without surgical intervention. The question as to how ACs should be treated is discussed.
headache, nausea, or visual disturbance, and no neurological dysfunctions. Skull radiography showed bulging of the right temporal region and thinning of the parietal bone. Cranial computed tomography (CT) revealed an AC of 5 cm in diameter in the right temporal region (Fig. 1 a, b). In the absence of clinical symptoms other than the osseous changes, a conservative approach was taken. Regular monitoring of the cyst over a period of 10 years showed a continuous decrease in size (Fig. 2a, b). The child is now aged 13 years, and CT shows almost complete disappearance of the cyst (Fig. 3 a, b).
Discussion Key words: Intracranial arachnoid cysts - Spontaneous regression - Treatment
Since Richard Bright's first report of a "serous cyst" in the brain in 1831 [4], arachnoid cysts (ACs) have been f o u n d in various locations [16, 17, 19]. However, the etiology and pathogenesis of these malformations of the arachnoid have remained unclear [12]. Focal disturbances o f cerebrospinal fluid circulation, infections, and vascular factors were incriminated [5, 10, 12]. In a large series [11] ACs accounted for approximately 1% of all atraumatic mass lesions. This n u m b e r m a y be an underestimate of the real incidence because with the advent of neuroimaging ACs have repeatedly been discovered fortuitously [14]. Surgical treatment has been advocated [5, 8 - 1 2 ] but the question regarding w h o m to treat and when remains open. We report a case o f spontaneous and nearly complete regression of a right temporal AC over a period o f 10 years.
Case report Palpable bulging of the right temporal skull was first noted at the age of 3 in an otherwise healthy child. There was no history of head trauma or preceding brain infection. On examination the psychomotor development was normal. There were no complaints of Offprint requests to. R. Weber
Little is k n o w n a b o u t the natural course o f ACs [1, 12] and spontaneous regression has rarely been reported in the literature [3, 7, 18, 20]. Different mechanisms have been suggested to be responsible for the spontaneous resolution of ACs. Because subdural h e m a t o m a or h y g r o m a was usually associated with spontaneous disappearance of ACs [7, 20], it was speculated that a tear in the cyst wall caused by t r a u m a m a y have led to the formation of a subdural h y g r o m a with consecutive absorption of the cyst fluid [19]. On the other hand, not all cases of AC with subdural h e m a t o m a have shown shrinkage of the cyst [13]. Another cause of spontaneous resolution was thought to be a communication between the cyst and the subarachnoid space. Whether direct transport through the cyst wall occurs [15] or whether the CSF is released through a valve-like mechanism [6] is still an open question. Some authors have suggested that fluid m a y be able to permeate the cyst wall freely [14], whereas others [6] have presented morphological evidence of active transcellular fluid transport. Controversy exists concerning the treatment of ACs. There is no doubt that surgical treatment is necessary in patients with raised intracranial pressure and corresponding clinical symptoms. Three types of treatment m a y be considered: cystoperitoneal shunting alone, shunting followed by craniotomy and excision o f the cyst, and excision alone [8, 9]. I f an excision is performed, histopathological diagnosis becomes possible and a tu-
415 viously, o u r case a n d the few r e p o r t e d cases o f s p o n t a n e o u s d i s a p p e a r a n c e o f A C s d o n o t offer sufficient indic a t i o n s r e g a r d i n g t r e a t m e n t , b u t t h e y d o suggest a m o r e c o n s e r v a t i v e a p p r o a c h in p a t i e n t s w i t h o u t c o m p l i c a t i o n s . W i t h the p o s s i b i l i t y o f n o n - i n v a s i v e a n d h a r m l e s s m o n i t o r i n g b y C T o r m a g n e t i c r e s o n a n c e i m a g i n g the n a t u r a l c o u r s e o f A C s s h o u l d be f o l l o w e d m o r e frequently.
References
Fig. 1 a, b. Cranial computed tomography (CT) scans at the age of 3 years showing a right temporal, hypodense lesion. Bulging of the right temporal bone is seen. The ventricular system appears normal Fig. 2a, b. Follow-up CT scans performed when the child was 10 years old, demonstrating reduction in cyst size
Fig. 3a, b. CT scans at age 13 years. The arachnoid cyst has almost completely disappeared
m o r m a y be excluded. I f a s h u n t s y s t e m is inserted, there is a risk o f s h u n t m a l f u n c t i o n [2]. H o w e v e r , u p to n o w studies reviewing the success o f surgical p r o c e d u r e s h a v e n o t t a k e n the p o s s i b i l i t y o f s p o n t a n e o u s r e m i s s i o n into a c c o u n t [1, 6, 11]. T h e p r e s e n t case argues in f a v o r o f a c o n s e r v a t i v e a p p r o a c h if there are n o r e l e v a n t clinical signs o f raised i n t r a c r a n i a l p r e s s u r e o r c r a n i a l nerve d y s f u n c t i o n , a n d especially in t h o s e cases w h e r e A C s r e p r e s e n t a c h a n c e finding. T h i n n i n g o f the c r a n i a l b o n e a l o n e s h o u l d n o t necessarily be r e g a r d e d as a n i n d i c a t i o n for surgery. O b -
1. Aicardi J, Bauman F (1975) Supratentorial extracerebral cysts in infants and children. J Neurol Neurosurg Psychiatry 38:57-68 2. Aoki N, Tatsuo S, Umezawa Y (1990) Slit ventricle syndrome after cyst-peritoneal shunting for the treatment of intracranial arachnoid cyst. Child's Nerv Syst 6:41-43 3. Beltramello A, Mazza C (1985) Spontaneous disappearance of a large middle fossa arachnoid cyst. Surg Neurol 24:181-183 4. Bright R (1831) Serous cysts in the arachnoid. In: Rees, Orme, et al (eds) Reports of medical cases selected with a view of illustrating the symptoms and cure of diseases by a reference to morbid anatomy, vol II: Diseases of the brain and nervous system, part I. Highley, London, pp 437 439 5. Choux M, Yanez A (1986) Arachnoid cysts. In: Hoffman HJ, Epstein F (eds) Disorders of the developing nervous system: diagnosis and treatment. Blackwell, Boston, pp 175-189 6. Go KG, Houthoff H J, Blaauw EH, Havinga P, Hartsuiker J (1984) Arachnoid cyst of the sylvia fissure. Evidence of fluid secretion. J Neurosurg 60:803-813 7. Inoue T, Matsushima T, Tashima S, Fukui M, Hasuo K (1987) Spontaneous disappearance of a middle fossa arachnoid cyst associated with subdural hematoma. Surg Neurol 28:447-450 8. Jones RFC, Warnock TH, Nayanar V, Gupta JMG (1989) Suprasellar arachnoid cysts: management by cyst wall resection. Neurosurgery 25:554-561 9. Locatelli D, Bonfanti N, Sfogliarini R, Gajno TM, Pezzotta S (1987) Arachnoid cysts: diagnosis and treatment. Child's Nerv Syst 3:121-124 10. Rengachary SS, Watanabe I, Brackett CE (1978) Pathogenesis of intracranial arachnoid cysts. Surg Neurol 9:139-144 11. Richard KE, Dahl K, Sanker P (1989) Long-term follow-up of children and juveniles with arachnoid cysts. Child's Nerv Syst 5:184-187 12. Robinson RG (1971) Congenital cysts of the brain: arachnoid malformation. Prog Neurol Surg 4:133-174 13. Romero FJ, Rovira M, Ibarra B, Piqueras J, Rovira M (1989) Arachnoid cysts with intracystic and subdural haematoma. Eur J Radiol 9:119-120 14. Sandler MA, Madrazo BL, Riga PM, Kellman GM, Beute GH, Berger JA, Keigley BA (1988) Ultrasound case of the day. Radiographics 8:358 361 15. Schachenmayr W, Friede RL (1979) Fine structure ofarachnoid cysts. J Neuropathol Exp Neurol 38:434-446 16. Spiegel SM, Nixon B, TerBrugge K, Chiu MC, Schutz H (1988) Arachnoid cyst of the velum interpositum. AJNR 9:981-983 17. Starshak RS, Meyer GA, Choi SK, Sty JR, Kovnar EA (1986) Arachnoid cyst of the collicular cistern. Child's Nerv Syst 2:144-148 18. Takagi K, Sasaki T, Basugi N (1986) Spontaneous disappearance of cerebellopontine angle arachnoid cyst: report of a case (in Japanese). No Shinkei Geka 15:295-299 19. Van der Mech6 FGA, Braakman R (1983) Arachnoid cysts in the middle cranial fossa: cause and treatment of progressive and non-progressive symptoms. J Neurol Neurosurg Psychiatry 46:1102-1107 20. Yamanouchi Y, Someda K, Oka N (1986) Spontaneous disappearance of middle fossa arachnoid cyst after head injury. Child's Nerv Syst 2:40-43
mGNS 9 Springer-Verlag 1991
Spontaneous regression of a temporal arachnoid cyst R. Weber 1, T. Voit 1, C. Lumenta 2, and H.-G. Lenard 1 1 Kinderklinik and 2 Neurochirurgische Klinik der Universitfit, Moorenstrasse 5, W-4000 Diisseldorf, Federal Republic of Germany Received September 18, 1990/Revised May 10, 1991
Abstract. Surgery is considered to be the standard therapy for arachnoid cysts (ACs). We report the case of a 13-year-old boy in w h o m a right temporal AC disappeared spontaneously over a period of 10 years. Bulging of the right temporal skull led to the detection of the cyst by c o m p u t e d t o m o g r a p h y (CT) scan at the age of 3 years. There were no other clinical symptoms. Subsequent CT scans showed spontaneous regression of the cyst without surgical intervention. The question as to how ACs should be treated is discussed.
headache, nausea, or visual disturbance, and no neurological dysfunctions. Skull radiography showed bulging of the right temporal region and thinning of the parietal bone. Cranial computed tomography (CT) revealed an AC of 5 cm in diameter in the right temporal region (Fig. 1 a, b). In the absence of clinical symptoms other than the osseous changes, a conservative approach was taken. Regular monitoring of the cyst over a period of 10 years showed a continuous decrease in size (Fig. 2a, b). The child is now aged 13 years, and CT shows almost complete disappearance of the cyst (Fig. 3 a, b).
Discussion Key words: Intracranial arachnoid cysts - Spontaneous regression - Treatment
Since Richard Bright's first report of a "serous cyst" in the brain in 1831 [4], arachnoid cysts (ACs) have been f o u n d in various locations [16, 17, 19]. However, the etiology and pathogenesis of these malformations of the arachnoid have remained unclear [12]. Focal disturbances o f cerebrospinal fluid circulation, infections, and vascular factors were incriminated [5, 10, 12]. In a large series [11] ACs accounted for approximately 1% of all atraumatic mass lesions. This n u m b e r m a y be an underestimate of the real incidence because with the advent of neuroimaging ACs have repeatedly been discovered fortuitously [14]. Surgical treatment has been advocated [5, 8 - 1 2 ] but the question regarding w h o m to treat and when remains open. We report a case o f spontaneous and nearly complete regression of a right temporal AC over a period o f 10 years.
Case report Palpable bulging of the right temporal skull was first noted at the age of 3 in an otherwise healthy child. There was no history of head trauma or preceding brain infection. On examination the psychomotor development was normal. There were no complaints of Offprint requests to. R. Weber
Little is k n o w n a b o u t the natural course o f ACs [1, 12] and spontaneous regression has rarely been reported in the literature [3, 7, 18, 20]. Different mechanisms have been suggested to be responsible for the spontaneous resolution of ACs. Because subdural h e m a t o m a or h y g r o m a was usually associated with spontaneous disappearance of ACs [7, 20], it was speculated that a tear in the cyst wall caused by t r a u m a m a y have led to the formation of a subdural h y g r o m a with consecutive absorption of the cyst fluid [19]. On the other hand, not all cases of AC with subdural h e m a t o m a have shown shrinkage of the cyst [13]. Another cause of spontaneous resolution was thought to be a communication between the cyst and the subarachnoid space. Whether direct transport through the cyst wall occurs [15] or whether the CSF is released through a valve-like mechanism [6] is still an open question. Some authors have suggested that fluid m a y be able to permeate the cyst wall freely [14], whereas others [6] have presented morphological evidence of active transcellular fluid transport. Controversy exists concerning the treatment of ACs. There is no doubt that surgical treatment is necessary in patients with raised intracranial pressure and corresponding clinical symptoms. Three types of treatment m a y be considered: cystoperitoneal shunting alone, shunting followed by craniotomy and excision o f the cyst, and excision alone [8, 9]. I f an excision is performed, histopathological diagnosis becomes possible and a tu-
415 viously, o u r case a n d the few r e p o r t e d cases o f s p o n t a n e o u s d i s a p p e a r a n c e o f A C s d o n o t offer sufficient indic a t i o n s r e g a r d i n g t r e a t m e n t , b u t t h e y d o suggest a m o r e c o n s e r v a t i v e a p p r o a c h in p a t i e n t s w i t h o u t c o m p l i c a t i o n s . W i t h the p o s s i b i l i t y o f n o n - i n v a s i v e a n d h a r m l e s s m o n i t o r i n g b y C T o r m a g n e t i c r e s o n a n c e i m a g i n g the n a t u r a l c o u r s e o f A C s s h o u l d be f o l l o w e d m o r e frequently.
References
Fig. 1 a, b. Cranial computed tomography (CT) scans at the age of 3 years showing a right temporal, hypodense lesion. Bulging of the right temporal bone is seen. The ventricular system appears normal Fig. 2a, b. Follow-up CT scans performed when the child was 10 years old, demonstrating reduction in cyst size
Fig. 3a, b. CT scans at age 13 years. The arachnoid cyst has almost completely disappeared
m o r m a y be excluded. I f a s h u n t s y s t e m is inserted, there is a risk o f s h u n t m a l f u n c t i o n [2]. H o w e v e r , u p to n o w studies reviewing the success o f surgical p r o c e d u r e s h a v e n o t t a k e n the p o s s i b i l i t y o f s p o n t a n e o u s r e m i s s i o n into a c c o u n t [1, 6, 11]. T h e p r e s e n t case argues in f a v o r o f a c o n s e r v a t i v e a p p r o a c h if there are n o r e l e v a n t clinical signs o f raised i n t r a c r a n i a l p r e s s u r e o r c r a n i a l nerve d y s f u n c t i o n , a n d especially in t h o s e cases w h e r e A C s r e p r e s e n t a c h a n c e finding. T h i n n i n g o f the c r a n i a l b o n e a l o n e s h o u l d n o t necessarily be r e g a r d e d as a n i n d i c a t i o n for surgery. O b -
1. Aicardi J, Bauman F (1975) Supratentorial extracerebral cysts in infants and children. J Neurol Neurosurg Psychiatry 38:57-68 2. Aoki N, Tatsuo S, Umezawa Y (1990) Slit ventricle syndrome after cyst-peritoneal shunting for the treatment of intracranial arachnoid cyst. Child's Nerv Syst 6:41-43 3. Beltramello A, Mazza C (1985) Spontaneous disappearance of a large middle fossa arachnoid cyst. Surg Neurol 24:181-183 4. Bright R (1831) Serous cysts in the arachnoid. In: Rees, Orme, et al (eds) Reports of medical cases selected with a view of illustrating the symptoms and cure of diseases by a reference to morbid anatomy, vol II: Diseases of the brain and nervous system, part I. Highley, London, pp 437 439 5. Choux M, Yanez A (1986) Arachnoid cysts. In: Hoffman HJ, Epstein F (eds) Disorders of the developing nervous system: diagnosis and treatment. Blackwell, Boston, pp 175-189 6. Go KG, Houthoff H J, Blaauw EH, Havinga P, Hartsuiker J (1984) Arachnoid cyst of the sylvia fissure. Evidence of fluid secretion. J Neurosurg 60:803-813 7. Inoue T, Matsushima T, Tashima S, Fukui M, Hasuo K (1987) Spontaneous disappearance of a middle fossa arachnoid cyst associated with subdural hematoma. Surg Neurol 28:447-450 8. Jones RFC, Warnock TH, Nayanar V, Gupta JMG (1989) Suprasellar arachnoid cysts: management by cyst wall resection. Neurosurgery 25:554-561 9. Locatelli D, Bonfanti N, Sfogliarini R, Gajno TM, Pezzotta S (1987) Arachnoid cysts: diagnosis and treatment. Child's Nerv Syst 3:121-124 10. Rengachary SS, Watanabe I, Brackett CE (1978) Pathogenesis of intracranial arachnoid cysts. Surg Neurol 9:139-144 11. Richard KE, Dahl K, Sanker P (1989) Long-term follow-up of children and juveniles with arachnoid cysts. Child's Nerv Syst 5:184-187 12. Robinson RG (1971) Congenital cysts of the brain: arachnoid malformation. Prog Neurol Surg 4:133-174 13. Romero FJ, Rovira M, Ibarra B, Piqueras J, Rovira M (1989) Arachnoid cysts with intracystic and subdural haematoma. Eur J Radiol 9:119-120 14. Sandler MA, Madrazo BL, Riga PM, Kellman GM, Beute GH, Berger JA, Keigley BA (1988) Ultrasound case of the day. Radiographics 8:358 361 15. Schachenmayr W, Friede RL (1979) Fine structure ofarachnoid cysts. J Neuropathol Exp Neurol 38:434-446 16. Spiegel SM, Nixon B, TerBrugge K, Chiu MC, Schutz H (1988) Arachnoid cyst of the velum interpositum. AJNR 9:981-983 17. Starshak RS, Meyer GA, Choi SK, Sty JR, Kovnar EA (1986) Arachnoid cyst of the collicular cistern. Child's Nerv Syst 2:144-148 18. Takagi K, Sasaki T, Basugi N (1986) Spontaneous disappearance of cerebellopontine angle arachnoid cyst: report of a case (in Japanese). No Shinkei Geka 15:295-299 19. Van der Mech6 FGA, Braakman R (1983) Arachnoid cysts in the middle cranial fossa: cause and treatment of progressive and non-progressive symptoms. J Neurol Neurosurg Psychiatry 46:1102-1107 20. Yamanouchi Y, Someda K, Oka N (1986) Spontaneous disappearance of middle fossa arachnoid cyst after head injury. Child's Nerv Syst 2:40-43
