J Neurosurg 50:515-518, 1979
Diagnosis and treatment of suprasellar arachnoid cyst Report of three cases
RA~ MURALI, M.D., F.R.C.S., AND FaED EPSTEIN, M.D. Department of Neurosurgery, New York University, and Bellevue Medical Center, New York, New York
v' Three cases of suprasellar arachnoid cysts in children are described. The importance of differentiating such a lesion from a dilated third ventricle is stressed. The value of computerized tomography with Conray ventriculography in preoperative diagnosis, symptomatology, and choice of treatment are discussed. KEY WORDS arachnoid cyst Conray ventriculography 9
9 suprasellar lesion
A
RACHNOID cysts form a well defined pathological entity. They account for about 1% of all intracranial space-occupying lesions. 13 Suprasellar arachnoid cysts comprise the least common variety, and review of the literature reveals only isolated case reports in this location? -6,12 Even in larger series, suprasellar arachnoid cysts are either not encountered at all, ~a or form only a small group? ,",18 With the advent of computerized tomography (CT) scanning, the presence of arachnoid cysts is revealed more readily, and a firm preoperative diagnosis can now be made, 1~ especially when the cyst is located in the more common middle cranial fossa or posterior fossa locations. However, suprasellar arachnoid cysts often present with hydrocephalus and may be easily mistaken for a dilated anterior third ventricle. It is important to differentiate the two, so that the proper treatment can be given. The following case reports are illustrative of this pathological entity.
9 computerized tomography
and the cyst exposed subfrontally and opened into the basal cisterns. The postoperative course was uneventful, the shunt was ultimately turned off; and the child, who is now 5 years old, is developmentally normal.
Case Reports Case 1
This 3-month-old infant presented with a history of a rapidly enlarging head. The anterior fontanel was bulging and the sutures were separated. A C T scan disclosed advanced hydrocephalus and a round lucency of cerebrospinal fluid (CSF) density in the region of the third ventricle (Fig. 1). A diagnosis of suprasellar arachnoid cyst was made, and an on-off shunt was inserted. Subsequently a craniotomy was performed, J. Neurosurg. / Volume 50/April, 1979
FIG. 1. Case 1. Computerized tomography scan showing marked hydrocephalus and a round lucency in the suprasellar region. 5]5
R. Murali and F. Epstein
Fie. 2. Case 2. Left: Computerized tomography scan showing hydrocephalus due to suprasellar arachnoid cyst. Note appearance of the head of a "bunny." Right: Scan after instillation of 2 ml of Conray 60% into the left frontal horn. Note obstruction at the foramen of Monro (arrow) and failure of contrast to enter the third ventricle.
Case 2 This 11-month-old child presented for evaluation of an enlarged head. A CT scan disclosed advanced hydrocephalus as well as a large round lucency of CSF density in the region of the third ventricle (Fig. 2 left).
A presumptive diagnosis of suprasellar arachnoid cyst was made, and 2 ml of Conray 60% was injected via the coronal suture into the right frontal horn. This confirmed that the foramen of Monro was obstructed (Fig. 2 right). A craniotomy was performed and the cyst opened into the basal cisterns. Approximately 6 weeks after surgery, the fontanel once again became full, and a CT scan disclosed that the cyst and hydrocephalus had recurred. A second craniotomy was performed at which time the cyst was exposed via the transventricular route and was found bulging through the foramen of Monro. The cyst was marsupialized into the ventricular system, and a ventriculoperitoneal shunt was placed at the same time. The child has since remained well.
Case 3
FIG. 3. Case 3. Computerized tomography scan showing suprasellar arachnoid cyst and the configuration of the head of a "bunny." 516
This 9-year-old child, who was shunted in the neonatal period for hydrocephalus, presented with progressive impairment of vision. Physical examination disclosed that the shunt pumped normally. Neurological examination was negative except for bilateral optic atrophy with reduction of visual acuity to 20/100 in the left eye, and 20/200 in the right eye. A CT scan disclosed that the ventricular system was small, but there was a round lucency of CSF density in the region of the third ventricle (Fig. 3). A Conray shunt scan demonstrated normal shunt function. A subfrontal craniotomy confirmed the presence of a suprasellar arachnoid cyst which was opened into th~ basal cisterns. Since surgery, the neurological status has been stable with regard to visual acuity, and the child is functioning normally.
J. Neurosurg. / Volume 50/April, 1979
Suprasellar arachnoid cyst
FIG. 4. Left: Computerized tomography scan of aqueductal stenosis showing a dilated anterior third ventricle resembling a suprasellar arachnoid cyst. Right: Higher cut showing a tapered posterior third ventricle.
Discussion
Suprasellar arachnoid cysts may become symptomatic in one of three ways: 1) in the neonatal period they can cause hydrocephalus; 2) in later years, they can present with progressive visual impairment; and 3) they can occasionally present with endocrine dysfunction, including precocious puberty? ,~ In our Case 3, the cyst was probably overlooked as the primary etiology of hydrocephalus since it only became symptomatic with increasing size and resultant optic chiasm and nerve compression. Before the advent of CT scanning, suprasellar arachnoid cysts were at times suspected preoperatively on the basis of angiography or pneumoencephalography. 9 Kasdon, et al., ~~ reported the first case of suprasellar arachnoid cyst that was diagnosed preoperatively on CT scan findings. With increasing dependence on CT scanning for diagnosis and treatment of hydrocephalus, suprasellar arachnoid cysts should be differentiated from a dilated third ventricle (Fig. 4 left). The most prominent diagnostic feature is the appearance of a fat, oval-to-round lucency in the region of the third ventricle. When the frontal horns are superimposed, the characteristic radiological appearance is very similar to the head of a "bunny" (Figs. 2 left and 3). Occasionally the third ventricle may have a round appearance in aqueduct stenosis. However, the tapered, enlarged posterior third ventricle is obvious on higher cuts (Fig. 4 right). For definitive diagnosis, a CT scan should be performed following intraventricular injection of a small volume of Conray 60% (1 to 2 ml). When hydroJ. Neurosurg. / Volume 5 0 / A p r i l , 1979
cephalus is secondary to a suprasellar cyst, the foramen of Monro is blocked and the Conray remains in the lateral ventricles into which it was injected (Fig. 2 right). In aqueductal stenosis or similar lesions in that area, Conray diffuses rapidly through the entire lateral ventricular system and outlines the dilated third ventricle. Although only rarely necessary, a definitive diagnosis may also be made by vertebrobasilar angiography. A dilated third ventricle stretches and elongates the anterior thalamo-perforating arteries but does not bow them. A suprasellar cyst will sharply bow these vessels. 7,* The present series is too small to make a definitive conclusion concerning appropriate therapy. Although the suprasellar arachnoid cyst may be exposed and evacuated subfrontally, transcallosally, or via the transventricular route, the question of which of these approaches is most likely to result in a permanent cure is unresolved. Although in the present series the subfrontal approach was satisfactory in two of three cases, it would seem that marsupialization into the ventricle might be more likely to maintain a permanent communication. In the case reported by Kasdon, et al., 1~ where the cyst was punctured and the dome resected, the cyst recurred in 2 months. On the second occasion, the cyst was resected, and a shunt tube was inserted and connected to a ventriculoperitoneal shunt with full resolution of symptoms. 1~ MilhoraP 1 also believes that some of these deep cysts are best treated by insertion of a shunt to drain into the peritoneal cavity, and illustrates this point with a case of supracollicular arachnoid cyst that was treated by shunting only. Opening the cyst into the basal cisterns is certainly more restricted in terms of the dimensions 5]7
R. Murali and F. Epstein of the communication and, therefore, probably less reliable. These lesions might be approached through a ventriculoscope and, widely opened into the ventricular system. The ventricular system itself can then be shunted if necessary. Such an approach might obviate the need for a major craniotomy without compromising direct visualization.
8.
9. 10.
References
1. Aicardi J, Bauman F: Supratentorial extracerebral cysts in infants and children. J Neurol Neurosurg Psychiatry 38:57-68, 1975 2. Anderson FM, Landing BH: Cerebral arachnoid cysts in infants. J Pediatr 69:88-96, 1966 3. Banna M: Arachnoid cysts in the hypophyseal area. Clin Radiol 25:323-326, 1974 4. Barlow A: Suprasellar arachnoid cyst. Arch Ophthalmol 14:53-60, 1935 5. Danziger J, Bloch S: Suprasellar arachnoid pouches. Br J Radioi 47:448-451, 1974 6. Faris AA, Bale GF, Cannon B: Arachnoid cyst of the third ventricle with precocious puberty. South Med J 64:1139-1142, 1971 7. George AE, Raybaud CH, Salamon G, et al: Anatomy of the thalamoperforating arteries with special emphasis
518
11. 12. 13.
on arteriography of the third ventricle: Part I. Am J Roentgenol 124:220-230, 1975 George AE, Salamon G, Kricheff I: Pathologic anatomy of the thalamoperforating arteries in lesions of the third ventricle: Part II. Am J Roentgenol 124:231-240, 1975 Harrison MJG: Cerebral arachnoid cysts in children. J Neurol Neurosurg Psychiatry 34:316-323, 1971 Kasdon DL, Douglas EA, Brougham MF: Suprasellar arachnoid cyst diagnosed preoperatively by computerized tomographic scanning. Surg Neurol 7: 299-303, 1977 Milhorat TH: Pediatric Neurosurgery: Contemporary Neurology Series, Vol 16. Philadelphia: FA Davis, 1977, pp 191-197 Ring BA, Waddington M: Primary arachnoid cysts of the sella turcica. Am J Roentgenul Radium Ther Nucl Med 98:611-615, 1966 Robinson RG: Congenital cysts of the brain: Arachnoid malformations. Prog Neurol Surg 4:133-174, 1971
Address reprint requests to: Fred Epstein, M.D., Department of Neurosurgery, New York University Medical Center, 550 First Avenue, New York, New York 10016.
J. Neurosurg. / Volume 50 / April, 1979
Diagnosis and treatment of suprasellar arachnoid cyst Report of three cases
RA~ MURALI, M.D., F.R.C.S., AND FaED EPSTEIN, M.D. Department of Neurosurgery, New York University, and Bellevue Medical Center, New York, New York
v' Three cases of suprasellar arachnoid cysts in children are described. The importance of differentiating such a lesion from a dilated third ventricle is stressed. The value of computerized tomography with Conray ventriculography in preoperative diagnosis, symptomatology, and choice of treatment are discussed. KEY WORDS arachnoid cyst Conray ventriculography 9
9 suprasellar lesion
A
RACHNOID cysts form a well defined pathological entity. They account for about 1% of all intracranial space-occupying lesions. 13 Suprasellar arachnoid cysts comprise the least common variety, and review of the literature reveals only isolated case reports in this location? -6,12 Even in larger series, suprasellar arachnoid cysts are either not encountered at all, ~a or form only a small group? ,",18 With the advent of computerized tomography (CT) scanning, the presence of arachnoid cysts is revealed more readily, and a firm preoperative diagnosis can now be made, 1~ especially when the cyst is located in the more common middle cranial fossa or posterior fossa locations. However, suprasellar arachnoid cysts often present with hydrocephalus and may be easily mistaken for a dilated anterior third ventricle. It is important to differentiate the two, so that the proper treatment can be given. The following case reports are illustrative of this pathological entity.
9 computerized tomography
and the cyst exposed subfrontally and opened into the basal cisterns. The postoperative course was uneventful, the shunt was ultimately turned off; and the child, who is now 5 years old, is developmentally normal.
Case Reports Case 1
This 3-month-old infant presented with a history of a rapidly enlarging head. The anterior fontanel was bulging and the sutures were separated. A C T scan disclosed advanced hydrocephalus and a round lucency of cerebrospinal fluid (CSF) density in the region of the third ventricle (Fig. 1). A diagnosis of suprasellar arachnoid cyst was made, and an on-off shunt was inserted. Subsequently a craniotomy was performed, J. Neurosurg. / Volume 50/April, 1979
FIG. 1. Case 1. Computerized tomography scan showing marked hydrocephalus and a round lucency in the suprasellar region. 5]5
R. Murali and F. Epstein
Fie. 2. Case 2. Left: Computerized tomography scan showing hydrocephalus due to suprasellar arachnoid cyst. Note appearance of the head of a "bunny." Right: Scan after instillation of 2 ml of Conray 60% into the left frontal horn. Note obstruction at the foramen of Monro (arrow) and failure of contrast to enter the third ventricle.
Case 2 This 11-month-old child presented for evaluation of an enlarged head. A CT scan disclosed advanced hydrocephalus as well as a large round lucency of CSF density in the region of the third ventricle (Fig. 2 left).
A presumptive diagnosis of suprasellar arachnoid cyst was made, and 2 ml of Conray 60% was injected via the coronal suture into the right frontal horn. This confirmed that the foramen of Monro was obstructed (Fig. 2 right). A craniotomy was performed and the cyst opened into the basal cisterns. Approximately 6 weeks after surgery, the fontanel once again became full, and a CT scan disclosed that the cyst and hydrocephalus had recurred. A second craniotomy was performed at which time the cyst was exposed via the transventricular route and was found bulging through the foramen of Monro. The cyst was marsupialized into the ventricular system, and a ventriculoperitoneal shunt was placed at the same time. The child has since remained well.
Case 3
FIG. 3. Case 3. Computerized tomography scan showing suprasellar arachnoid cyst and the configuration of the head of a "bunny." 516
This 9-year-old child, who was shunted in the neonatal period for hydrocephalus, presented with progressive impairment of vision. Physical examination disclosed that the shunt pumped normally. Neurological examination was negative except for bilateral optic atrophy with reduction of visual acuity to 20/100 in the left eye, and 20/200 in the right eye. A CT scan disclosed that the ventricular system was small, but there was a round lucency of CSF density in the region of the third ventricle (Fig. 3). A Conray shunt scan demonstrated normal shunt function. A subfrontal craniotomy confirmed the presence of a suprasellar arachnoid cyst which was opened into th~ basal cisterns. Since surgery, the neurological status has been stable with regard to visual acuity, and the child is functioning normally.
J. Neurosurg. / Volume 50/April, 1979
Suprasellar arachnoid cyst
FIG. 4. Left: Computerized tomography scan of aqueductal stenosis showing a dilated anterior third ventricle resembling a suprasellar arachnoid cyst. Right: Higher cut showing a tapered posterior third ventricle.
Discussion
Suprasellar arachnoid cysts may become symptomatic in one of three ways: 1) in the neonatal period they can cause hydrocephalus; 2) in later years, they can present with progressive visual impairment; and 3) they can occasionally present with endocrine dysfunction, including precocious puberty? ,~ In our Case 3, the cyst was probably overlooked as the primary etiology of hydrocephalus since it only became symptomatic with increasing size and resultant optic chiasm and nerve compression. Before the advent of CT scanning, suprasellar arachnoid cysts were at times suspected preoperatively on the basis of angiography or pneumoencephalography. 9 Kasdon, et al., ~~ reported the first case of suprasellar arachnoid cyst that was diagnosed preoperatively on CT scan findings. With increasing dependence on CT scanning for diagnosis and treatment of hydrocephalus, suprasellar arachnoid cysts should be differentiated from a dilated third ventricle (Fig. 4 left). The most prominent diagnostic feature is the appearance of a fat, oval-to-round lucency in the region of the third ventricle. When the frontal horns are superimposed, the characteristic radiological appearance is very similar to the head of a "bunny" (Figs. 2 left and 3). Occasionally the third ventricle may have a round appearance in aqueduct stenosis. However, the tapered, enlarged posterior third ventricle is obvious on higher cuts (Fig. 4 right). For definitive diagnosis, a CT scan should be performed following intraventricular injection of a small volume of Conray 60% (1 to 2 ml). When hydroJ. Neurosurg. / Volume 5 0 / A p r i l , 1979
cephalus is secondary to a suprasellar cyst, the foramen of Monro is blocked and the Conray remains in the lateral ventricles into which it was injected (Fig. 2 right). In aqueductal stenosis or similar lesions in that area, Conray diffuses rapidly through the entire lateral ventricular system and outlines the dilated third ventricle. Although only rarely necessary, a definitive diagnosis may also be made by vertebrobasilar angiography. A dilated third ventricle stretches and elongates the anterior thalamo-perforating arteries but does not bow them. A suprasellar cyst will sharply bow these vessels. 7,* The present series is too small to make a definitive conclusion concerning appropriate therapy. Although the suprasellar arachnoid cyst may be exposed and evacuated subfrontally, transcallosally, or via the transventricular route, the question of which of these approaches is most likely to result in a permanent cure is unresolved. Although in the present series the subfrontal approach was satisfactory in two of three cases, it would seem that marsupialization into the ventricle might be more likely to maintain a permanent communication. In the case reported by Kasdon, et al., 1~ where the cyst was punctured and the dome resected, the cyst recurred in 2 months. On the second occasion, the cyst was resected, and a shunt tube was inserted and connected to a ventriculoperitoneal shunt with full resolution of symptoms. 1~ MilhoraP 1 also believes that some of these deep cysts are best treated by insertion of a shunt to drain into the peritoneal cavity, and illustrates this point with a case of supracollicular arachnoid cyst that was treated by shunting only. Opening the cyst into the basal cisterns is certainly more restricted in terms of the dimensions 5]7
R. Murali and F. Epstein of the communication and, therefore, probably less reliable. These lesions might be approached through a ventriculoscope and, widely opened into the ventricular system. The ventricular system itself can then be shunted if necessary. Such an approach might obviate the need for a major craniotomy without compromising direct visualization.
8.
9. 10.
References
1. Aicardi J, Bauman F: Supratentorial extracerebral cysts in infants and children. J Neurol Neurosurg Psychiatry 38:57-68, 1975 2. Anderson FM, Landing BH: Cerebral arachnoid cysts in infants. J Pediatr 69:88-96, 1966 3. Banna M: Arachnoid cysts in the hypophyseal area. Clin Radiol 25:323-326, 1974 4. Barlow A: Suprasellar arachnoid cyst. Arch Ophthalmol 14:53-60, 1935 5. Danziger J, Bloch S: Suprasellar arachnoid pouches. Br J Radioi 47:448-451, 1974 6. Faris AA, Bale GF, Cannon B: Arachnoid cyst of the third ventricle with precocious puberty. South Med J 64:1139-1142, 1971 7. George AE, Raybaud CH, Salamon G, et al: Anatomy of the thalamoperforating arteries with special emphasis
518
11. 12. 13.
on arteriography of the third ventricle: Part I. Am J Roentgenol 124:220-230, 1975 George AE, Salamon G, Kricheff I: Pathologic anatomy of the thalamoperforating arteries in lesions of the third ventricle: Part II. Am J Roentgenol 124:231-240, 1975 Harrison MJG: Cerebral arachnoid cysts in children. J Neurol Neurosurg Psychiatry 34:316-323, 1971 Kasdon DL, Douglas EA, Brougham MF: Suprasellar arachnoid cyst diagnosed preoperatively by computerized tomographic scanning. Surg Neurol 7: 299-303, 1977 Milhorat TH: Pediatric Neurosurgery: Contemporary Neurology Series, Vol 16. Philadelphia: FA Davis, 1977, pp 191-197 Ring BA, Waddington M: Primary arachnoid cysts of the sella turcica. Am J Roentgenul Radium Ther Nucl Med 98:611-615, 1966 Robinson RG: Congenital cysts of the brain: Arachnoid malformations. Prog Neurol Surg 4:133-174, 1971
Address reprint requests to: Fred Epstein, M.D., Department of Neurosurgery, New York University Medical Center, 550 First Avenue, New York, New York 10016.
J. Neurosurg. / Volume 50 / April, 1979
![[«De novo» development of a suprasellar arachnoid cyst].](/assets/img/hold.png)
