- Email: [email protected]
Suprasellar masses
Suprasellar By A. Alan Chambers,
Robert
EFORE dealing with abnormalities of the third ventricle and the suprasellar region, the normal anatomy of these areas should be studied.‘3233 The craniopharyngioma is a suprasellar tumor
B
From the Department of Radiology, University Hospital and Good Samaritan Hospital, Cincinnati, OH. A. Alan Chambers: Associate Professor of Radiology, University of Cincinnati College of Medicine. Robert R. Lukin: Professor of Radiology, University of Cincinnati College of Medicine. Thomas A. Tomsick: Associate Professor of Radiology, University of Cincinnati College of Medicine. Address reprint requests to A. A. Chambers, M.D., Department of Radiology, University Hospital, 234 Goodman Street, Cincinnati, OH 45267. 0 1984 by Grune & Stratton. Inc. 0037-I 98X/84/1902-0001$01.00/0
Fig. 1. Typical calcified cystic craniopharyngioma. ventricles by upward extension to involve the foramen enhanced after contrast medium (not shown).
84
Masses
R. Lukin, and Thomas
A. Tomsick
that can be seen at any age, but rarely presents before 2 yr. Characteristically, the tumor is cystic and calcified to some extent (Fig. 1). It calcifies in about 80% of children and in about 40% of adults.* Craniopharyngioma may on occasion be of uniformly high density on CT. This usually indicates a solid tumor, but it may rarely prove to be a cyst with high density contents (Fig. 2). When a craniopharyngioma enhancesuniformly on CT, it may be difficult to distinguish from a chromophobe adenoma or giant aneurysm. A noncalcified low density craniopharyngioma is difficult to distinguish from an epidermoid or arachnoid cyst4 Rarely, craniopharyngioma arises in the third ventricle, usually presenting with ventricular obstruction.5 Cofloid cyst occurs at the foramen of Monro in the anterosuperior portion of the third ventri-
This predominantly cystic tumor is large enough to obstruct the of Monro. The wall at the base is heavily calcified. Only the cyst wall
Seminars in Roenrgenology,
Vol. XIX, No. 2 (April), 1984
SUPRASELLAR
85
MASSES
Table
1. Histologic
Classification
of Pineal Tumors*
Pineal cell origin Pineocytoma Pineoblastoma Germ cell origin Teratoma Germinoma (atypical pineal teratoma, suprasellar germinoma. ectopic pinealomal Embryonal cell carcinoma (endodermal sinus tumor) Choriocarcinoma Other cell origin Glioma Ganglioneuroma. ganglioglioma --*Source: Russell and Rubinstein.8
Fig. 2. Atypical high density craniopharyngioma. contrast CT shows high density fluid-filled mass. ingly, the high density mass does not enhance.
NonInterest-
cle. It is spherical and easy to see on CT because of its high density (Fig. 3). The lateral ventricles usually show symmetric dilatation, while the third ventricle collapses and may be difficult to see.’ Colloid cysts seldom enhance significantly.’ The slight enhancement observed is probably attributable to the choroid plexus wrapped around the cyst. IHowever, it has been shown that a double dose of contrast medium will produce a significant enhancement.6.7 Colloid cyst may occasionally be of brain density (isodense) and difhcult to diagnose (Fig. 4). On high resolution CT, the venous angles (internal cerebral vein) and fornices may be separated at the foramen of Monro. These signs plus large lateral ventricles and a collapsed third ventricle indicate a mass at the foramen of Monro. High resolution CT has all but eliminated the need for ventriculographic demonstration of a colloid cyst. Pinealoma refers to a group of tumors of several tissue types in the pineal region (Table I).” Pineocytoma and pineoblastoma are the only two tumors of purely pineal origin, and comprise about 20% of large series of pinealomas. Teratomatous tumors (teratoma, germinoma, and several other tumors of germ cell origin) are the most common of the pinealomas and account for
50s.’ Most germinomas (80%) occur in males from 15-25 yr of age.’ Teratomatous tumors originate from midline inclusions of multipotential cells of one or more germ layers during early development of the brain.“’ Gliomas of brain parenchyma adjacent to the pineal are often classified as pinealomas. CT is extremely helpful in differentiating the pinealomas. Obstructive hydrocephalus occurs early in their course Germinoma is higher than brain density and punctate calcification may be present throughout the lesion (Fig. 5). Germinoma of the pineal region obliterates the posterior third ventricle
Characteristic colloid cyst (noncontrast Fig. 3. cyst measured 70 HU on this scan and increased after contrast enhancement.
CT). The to 75 HU
86
CHAMEERS,
LUKIN,
AND TOMSICK
Colloid cyst. (A) The mass (straight arrow) is nearly isodense. The foramen of Monro is obstructed with enlarged Fig. 4. lateral ventricles end collapsed third ventricle (curved arrow). (B) After contrast medium there is no enhancement of the cyst. Vascular structures (internal cerebral veins) are split anteriorly (arrows), contouring the posterior cyst wall.
and distorts adjacent structures, such as the quadrigeminal cistern. The tumor may extend directly into adjacent tissue or seed along the subarachnoid space. The tumor enhances uniformly. It frequently shows excellent response to radiation therapy. Teratoma is almost totally restricted to males in the first three decades of life.* It is usually partly calcified and occasionally contains formed
elements, such as teeth. The noncalcified portion of the teratoma tends to be hypodense because of fatty or cystic components. Minima1 contrast enhancement is the rule. If striking contrast enhancement is observed, malignant change should be considered. Pineocytoma and pineoblastoma have been infrequently reported.‘,” Russell and Rubinstein8 collected 2 1 cases, 10 of which were pineo-
Germinoma of pineal origin with spread into the third ventricle, hypothalamus, and suprasellar region. (Aj Before Fig. 5. contrast injection. The tissue mass of the pineal is larger than the generous pineal calcification. lsodense irregular tumor obliterates a portion of the third ventricle. (Bj Pineel region section. Pronounced and uniform enhancement around the calcification. (C) Pineel and third ventricular section after contrast medium. Note the anterior extension of the tumor.
SUPRASELLAR
MASSES
blastoma; 6 of these occurred in the first decade. The more differentiated tumor (pineocytoma) occurred at any age. In 10 cases in one series, 7 pineoblastomas and 3 pineocytomas, intracranial metastasis developed through cerebrospinal fluid pathways.’ Sex distribution was equal. Because of their rarity, it is impossible for a single institution to gather sufficient material to generalize about the CT appearance of these tumors. In the published cases, the tumors have been solid, sometimes containing calcium, and usually enhancing (Fig. 6). The findings are similar to those of a geminoma, but less opaque before contrast. A pineal mass in a female is likely to be one of these tumors.‘.” Gliomas of the pineal or adjacent structures may present a variable CT appearance, as they do elsewhere. The tumor enhances irregularly. Glioma accounts for about 25% of pinealomas. Neoplastic calcification is seldom present, although the pineal gland itself may be calcified.’ Meningioma of the tentorial edge may present in the pineal region. Uniform enhancement is a helpful diagnostic feature. Coronal sections may be necessary to clemonstrate the continuity with the tentorium. Vein of Galen (aneurysm may appear as a mass of greater than brain density, similar to a germinoma (Fig. 7). It is common in young children, but may be seen in adults. The diagnosis is established by angiography. A solitary metastasis from an extracranial tumor may also mimic a primary pineal tumor (Fig. 8). The term ectopic pineafoma is often applied to suprasellar hypothalamic germinoma.*,” The
Fig. 6. Pineoblastoma. This 26yr-old woman presented 2% yr ago with headaches and paresis of upward gaze. She remains wall after surgery. radiation, and ventricular shunting. Proven by operation. (A) Calcification is present throughout the high density tumor. (61 After contrast the pineoblastoma enhanced uniformly.
a7
name is unfortunate, since it is neither truly ectopic nor does it involve the pineal or represent a metastasis from a pineal tumor. This germinoma is distinct from the one that extends along the third ventricular wall to the hypothalamus or one that has metastasized through the CSF to the anterior third ventricle. The tumor appears in the first three decades as a solid enhancing suprasellar mass (Fig. 9). An enhancing suprasellar mass with a normal sella turcica should suggest this tumor. Suprasellar arachnoid cyst with accompanying hydrocephalus may be easily mistaken for hydrocephalus secondary to aqueduct stenosis. The arachnoid cyst lies in the position of the third ventricle (Fig. lo), but is much larger and rounder than a distended third ventricle. It occupies the suprasellar cistern and sella. The cyst may follow the cleavage planes of the adjacent brain, extending laterally into the Sylvian fissure and inferiorly between the clivus and pons. This location is characteristic of extraaxial suprasellar cysts and neoplasms. Suprasellar arachnoid cyst usually presents before the age of 20 yr.4 About 60% of the patients have hydrocephalus and 30% have loss of visual acuity, making this an important curable lesion. Arachnoid cyst occurs in a variety of intracranial locations. CT scanning has made the diagnosis of suprasellar arachnoid cyst much easier. The cyst and frontal horns often have a “bunny rabbit” appearance I2 along with disproportionate widening of the third ventricle and less striking dilatation of the frontal horns and lateral ventricles. Metrizamide or air injected into a lateral ventri-
CHAMBERS,
LUKIN,
AND TOMSICK
Fig. 7. Vein of Gelen aneurysm in 39-y-old man. (A) CT after contrast medium shows en enhancing posterior third ventricular lesion. jB) Lateral carotid angiogram confirms the CT diagnosis. Internal and external carotid branches supply a complex vascular malformation that drain into the vein of Galen.
cle or lumbar subarachnoid space may enter the cyst only after a delay. Similar lesions that may be difficult to differentiate from arachnoid cyst are epidermoid and craniopharyngioma. Epidermoid tumor, like arachnoid cyst, seldom calcifies. Dermoid and
craniopharyngioma frequently calcify and may show fat density. Epidermoid usually measures between 0 and 10 Hounsfield units. This is about the same as spinal fluid and also the same as the contents of an arachnoid cyst. Thus, distinguishing a small epidermoid from a suprasellar arach-
Metastatic cholangiocarcinoma to the pineel. (A) Noncontrast CT shows pineal mass. (B) After Fig. 8. slightly higher level shows the pineal mass and several additional small enhancing deposits.
contrast
injection,
a
SUPRASELLAR
89
MASSES
noid cyst may be impossible. The larger epidermoid has an irregualr contour. Malignant glioma and ependymomu arise in the hypothalamus contiguous with the third ventricle. Malignant papilloma of the third ventricular choroid plexus may arise in the third ventricle. These are rare tumors that obstruct the ventricles and cause hydrocephalus as a result of obstruction or excessive spinal fluid production. In addition, meningioma, aneurysm, arteriovenous malformation, tuberous sclerosis, and cysticercosis may involve the third ventricle.
ACKNOWLEDGMENTS
Fig. 9. Ectopic pinealoma in an 18-yr-old woman. Note obliteration of the suprasellar cistern and anterior third ventricle. There is uniform enhancement of the tumor.
Fig. 10. Suprasellar arachnoid cyst. IA, 8) The apparent expansion of the pontine and suprasellar cisterns are due to extension of the cyst into these natural areas of cleavage. (C, D) Displacement of the 3rd ventricle by the cyst. Although the appearance suggests a dilated 3rd ventricle, this is the arachnoid cyst itself. Note the “bunny rabbit” appearance.’
Our thanks are due to Dr. Corning Benton and Dr. Richard Towbin, Cincinnati Children’s Hospital. and to Dr. John M. Tew. Chief of the Division of Neurosurgery. Good Samaritan and liniversity Hospitals. Cincinnati
CHAMBERS,
90
LUKIN,
AND TOMSICK
REFERENCES I. Naidich TP, Pudlowski RM, Leeds NE, et al: The normal contrast-enhanced computed axial tomogram of the brain. J Comput Assist Tomogr 1977;l: 16-29 2. Rao KCVG, Lee SN: Cranial Computed Tomography. New York: McGraw-Hill, 1983:3 14-3 17 3. Zimmerman RA, Bilaniuk LT: Age-related incidence of pineal calcification detected by computed tomography. Radiology 1982; 1421659-662 4. Hoffman HJ, Hendrick EB, Humphreys RP, et al: Investigation and management of suprasellar arachnoid I982;5 1597-602 cysts. J Neurosurg 5. Matthews Am J Neuroradiol
FD: lntraventricular
craniopharyngioma.
1983;4:984-985
6. Ganti SP, Antones JL, Louis KM, et al: Computed tomography in the diagnosis of colloid cysts of the third 1981;138:385-391 ventricle. Radiology
7. Davis JM, Davis KR, Newhouse J, et al: Expanded high iodine dose in computed cranial tomography: A preliminary report. Radiology 1979;131:373-380 8. Russell DS, Rubinstein LJ: Pathology of Tumours of the Nervous System (ed 4). Baltimore: Williams and Wilkins, 1977 9. Maciewicz RJ, Davis KR: Case records of the Massachusetts General Hospital. N Engl J Med 1983;309:542549
10. Zimmerman RA, Bilaniuk LT. Wook J, et al: Computed tomography of pineal, parapineal and histologically related tumors. Radiology 1980;137:669-677 I I. Takeuchi J, Handa H, Otsuka S, et al: Neuroradiological aspects of suprasellar germinoma. Neuroradiology 1979;17:153-159 12. Murali R, Epstein F: Diagnosis and treatment of 1979;50:5 15-5 18 suprasellar arachnoid cyst. J Neurosurg
Robert
EFORE dealing with abnormalities of the third ventricle and the suprasellar region, the normal anatomy of these areas should be studied.‘3233 The craniopharyngioma is a suprasellar tumor
B
From the Department of Radiology, University Hospital and Good Samaritan Hospital, Cincinnati, OH. A. Alan Chambers: Associate Professor of Radiology, University of Cincinnati College of Medicine. Robert R. Lukin: Professor of Radiology, University of Cincinnati College of Medicine. Thomas A. Tomsick: Associate Professor of Radiology, University of Cincinnati College of Medicine. Address reprint requests to A. A. Chambers, M.D., Department of Radiology, University Hospital, 234 Goodman Street, Cincinnati, OH 45267. 0 1984 by Grune & Stratton. Inc. 0037-I 98X/84/1902-0001$01.00/0
Fig. 1. Typical calcified cystic craniopharyngioma. ventricles by upward extension to involve the foramen enhanced after contrast medium (not shown).
84
Masses
R. Lukin, and Thomas
A. Tomsick
that can be seen at any age, but rarely presents before 2 yr. Characteristically, the tumor is cystic and calcified to some extent (Fig. 1). It calcifies in about 80% of children and in about 40% of adults.* Craniopharyngioma may on occasion be of uniformly high density on CT. This usually indicates a solid tumor, but it may rarely prove to be a cyst with high density contents (Fig. 2). When a craniopharyngioma enhancesuniformly on CT, it may be difficult to distinguish from a chromophobe adenoma or giant aneurysm. A noncalcified low density craniopharyngioma is difficult to distinguish from an epidermoid or arachnoid cyst4 Rarely, craniopharyngioma arises in the third ventricle, usually presenting with ventricular obstruction.5 Cofloid cyst occurs at the foramen of Monro in the anterosuperior portion of the third ventri-
This predominantly cystic tumor is large enough to obstruct the of Monro. The wall at the base is heavily calcified. Only the cyst wall
Seminars in Roenrgenology,
Vol. XIX, No. 2 (April), 1984
SUPRASELLAR
85
MASSES
Table
1. Histologic
Classification
of Pineal Tumors*
Pineal cell origin Pineocytoma Pineoblastoma Germ cell origin Teratoma Germinoma (atypical pineal teratoma, suprasellar germinoma. ectopic pinealomal Embryonal cell carcinoma (endodermal sinus tumor) Choriocarcinoma Other cell origin Glioma Ganglioneuroma. ganglioglioma --*Source: Russell and Rubinstein.8
Fig. 2. Atypical high density craniopharyngioma. contrast CT shows high density fluid-filled mass. ingly, the high density mass does not enhance.
NonInterest-
cle. It is spherical and easy to see on CT because of its high density (Fig. 3). The lateral ventricles usually show symmetric dilatation, while the third ventricle collapses and may be difficult to see.’ Colloid cysts seldom enhance significantly.’ The slight enhancement observed is probably attributable to the choroid plexus wrapped around the cyst. IHowever, it has been shown that a double dose of contrast medium will produce a significant enhancement.6.7 Colloid cyst may occasionally be of brain density (isodense) and difhcult to diagnose (Fig. 4). On high resolution CT, the venous angles (internal cerebral vein) and fornices may be separated at the foramen of Monro. These signs plus large lateral ventricles and a collapsed third ventricle indicate a mass at the foramen of Monro. High resolution CT has all but eliminated the need for ventriculographic demonstration of a colloid cyst. Pinealoma refers to a group of tumors of several tissue types in the pineal region (Table I).” Pineocytoma and pineoblastoma are the only two tumors of purely pineal origin, and comprise about 20% of large series of pinealomas. Teratomatous tumors (teratoma, germinoma, and several other tumors of germ cell origin) are the most common of the pinealomas and account for
50s.’ Most germinomas (80%) occur in males from 15-25 yr of age.’ Teratomatous tumors originate from midline inclusions of multipotential cells of one or more germ layers during early development of the brain.“’ Gliomas of brain parenchyma adjacent to the pineal are often classified as pinealomas. CT is extremely helpful in differentiating the pinealomas. Obstructive hydrocephalus occurs early in their course Germinoma is higher than brain density and punctate calcification may be present throughout the lesion (Fig. 5). Germinoma of the pineal region obliterates the posterior third ventricle
Characteristic colloid cyst (noncontrast Fig. 3. cyst measured 70 HU on this scan and increased after contrast enhancement.
CT). The to 75 HU
86
CHAMEERS,
LUKIN,
AND TOMSICK
Colloid cyst. (A) The mass (straight arrow) is nearly isodense. The foramen of Monro is obstructed with enlarged Fig. 4. lateral ventricles end collapsed third ventricle (curved arrow). (B) After contrast medium there is no enhancement of the cyst. Vascular structures (internal cerebral veins) are split anteriorly (arrows), contouring the posterior cyst wall.
and distorts adjacent structures, such as the quadrigeminal cistern. The tumor may extend directly into adjacent tissue or seed along the subarachnoid space. The tumor enhances uniformly. It frequently shows excellent response to radiation therapy. Teratoma is almost totally restricted to males in the first three decades of life.* It is usually partly calcified and occasionally contains formed
elements, such as teeth. The noncalcified portion of the teratoma tends to be hypodense because of fatty or cystic components. Minima1 contrast enhancement is the rule. If striking contrast enhancement is observed, malignant change should be considered. Pineocytoma and pineoblastoma have been infrequently reported.‘,” Russell and Rubinstein8 collected 2 1 cases, 10 of which were pineo-
Germinoma of pineal origin with spread into the third ventricle, hypothalamus, and suprasellar region. (Aj Before Fig. 5. contrast injection. The tissue mass of the pineal is larger than the generous pineal calcification. lsodense irregular tumor obliterates a portion of the third ventricle. (Bj Pineel region section. Pronounced and uniform enhancement around the calcification. (C) Pineel and third ventricular section after contrast medium. Note the anterior extension of the tumor.
SUPRASELLAR
MASSES
blastoma; 6 of these occurred in the first decade. The more differentiated tumor (pineocytoma) occurred at any age. In 10 cases in one series, 7 pineoblastomas and 3 pineocytomas, intracranial metastasis developed through cerebrospinal fluid pathways.’ Sex distribution was equal. Because of their rarity, it is impossible for a single institution to gather sufficient material to generalize about the CT appearance of these tumors. In the published cases, the tumors have been solid, sometimes containing calcium, and usually enhancing (Fig. 6). The findings are similar to those of a geminoma, but less opaque before contrast. A pineal mass in a female is likely to be one of these tumors.‘.” Gliomas of the pineal or adjacent structures may present a variable CT appearance, as they do elsewhere. The tumor enhances irregularly. Glioma accounts for about 25% of pinealomas. Neoplastic calcification is seldom present, although the pineal gland itself may be calcified.’ Meningioma of the tentorial edge may present in the pineal region. Uniform enhancement is a helpful diagnostic feature. Coronal sections may be necessary to clemonstrate the continuity with the tentorium. Vein of Galen (aneurysm may appear as a mass of greater than brain density, similar to a germinoma (Fig. 7). It is common in young children, but may be seen in adults. The diagnosis is established by angiography. A solitary metastasis from an extracranial tumor may also mimic a primary pineal tumor (Fig. 8). The term ectopic pineafoma is often applied to suprasellar hypothalamic germinoma.*,” The
Fig. 6. Pineoblastoma. This 26yr-old woman presented 2% yr ago with headaches and paresis of upward gaze. She remains wall after surgery. radiation, and ventricular shunting. Proven by operation. (A) Calcification is present throughout the high density tumor. (61 After contrast the pineoblastoma enhanced uniformly.
a7
name is unfortunate, since it is neither truly ectopic nor does it involve the pineal or represent a metastasis from a pineal tumor. This germinoma is distinct from the one that extends along the third ventricular wall to the hypothalamus or one that has metastasized through the CSF to the anterior third ventricle. The tumor appears in the first three decades as a solid enhancing suprasellar mass (Fig. 9). An enhancing suprasellar mass with a normal sella turcica should suggest this tumor. Suprasellar arachnoid cyst with accompanying hydrocephalus may be easily mistaken for hydrocephalus secondary to aqueduct stenosis. The arachnoid cyst lies in the position of the third ventricle (Fig. lo), but is much larger and rounder than a distended third ventricle. It occupies the suprasellar cistern and sella. The cyst may follow the cleavage planes of the adjacent brain, extending laterally into the Sylvian fissure and inferiorly between the clivus and pons. This location is characteristic of extraaxial suprasellar cysts and neoplasms. Suprasellar arachnoid cyst usually presents before the age of 20 yr.4 About 60% of the patients have hydrocephalus and 30% have loss of visual acuity, making this an important curable lesion. Arachnoid cyst occurs in a variety of intracranial locations. CT scanning has made the diagnosis of suprasellar arachnoid cyst much easier. The cyst and frontal horns often have a “bunny rabbit” appearance I2 along with disproportionate widening of the third ventricle and less striking dilatation of the frontal horns and lateral ventricles. Metrizamide or air injected into a lateral ventri-
CHAMBERS,
LUKIN,
AND TOMSICK
Fig. 7. Vein of Gelen aneurysm in 39-y-old man. (A) CT after contrast medium shows en enhancing posterior third ventricular lesion. jB) Lateral carotid angiogram confirms the CT diagnosis. Internal and external carotid branches supply a complex vascular malformation that drain into the vein of Galen.
cle or lumbar subarachnoid space may enter the cyst only after a delay. Similar lesions that may be difficult to differentiate from arachnoid cyst are epidermoid and craniopharyngioma. Epidermoid tumor, like arachnoid cyst, seldom calcifies. Dermoid and
craniopharyngioma frequently calcify and may show fat density. Epidermoid usually measures between 0 and 10 Hounsfield units. This is about the same as spinal fluid and also the same as the contents of an arachnoid cyst. Thus, distinguishing a small epidermoid from a suprasellar arach-
Metastatic cholangiocarcinoma to the pineel. (A) Noncontrast CT shows pineal mass. (B) After Fig. 8. slightly higher level shows the pineal mass and several additional small enhancing deposits.
contrast
injection,
a
SUPRASELLAR
89
MASSES
noid cyst may be impossible. The larger epidermoid has an irregualr contour. Malignant glioma and ependymomu arise in the hypothalamus contiguous with the third ventricle. Malignant papilloma of the third ventricular choroid plexus may arise in the third ventricle. These are rare tumors that obstruct the ventricles and cause hydrocephalus as a result of obstruction or excessive spinal fluid production. In addition, meningioma, aneurysm, arteriovenous malformation, tuberous sclerosis, and cysticercosis may involve the third ventricle.
ACKNOWLEDGMENTS
Fig. 9. Ectopic pinealoma in an 18-yr-old woman. Note obliteration of the suprasellar cistern and anterior third ventricle. There is uniform enhancement of the tumor.
Fig. 10. Suprasellar arachnoid cyst. IA, 8) The apparent expansion of the pontine and suprasellar cisterns are due to extension of the cyst into these natural areas of cleavage. (C, D) Displacement of the 3rd ventricle by the cyst. Although the appearance suggests a dilated 3rd ventricle, this is the arachnoid cyst itself. Note the “bunny rabbit” appearance.’
Our thanks are due to Dr. Corning Benton and Dr. Richard Towbin, Cincinnati Children’s Hospital. and to Dr. John M. Tew. Chief of the Division of Neurosurgery. Good Samaritan and liniversity Hospitals. Cincinnati
CHAMBERS,
90
LUKIN,
AND TOMSICK
REFERENCES I. Naidich TP, Pudlowski RM, Leeds NE, et al: The normal contrast-enhanced computed axial tomogram of the brain. J Comput Assist Tomogr 1977;l: 16-29 2. Rao KCVG, Lee SN: Cranial Computed Tomography. New York: McGraw-Hill, 1983:3 14-3 17 3. Zimmerman RA, Bilaniuk LT: Age-related incidence of pineal calcification detected by computed tomography. Radiology 1982; 1421659-662 4. Hoffman HJ, Hendrick EB, Humphreys RP, et al: Investigation and management of suprasellar arachnoid I982;5 1597-602 cysts. J Neurosurg 5. Matthews Am J Neuroradiol
FD: lntraventricular
craniopharyngioma.
1983;4:984-985
6. Ganti SP, Antones JL, Louis KM, et al: Computed tomography in the diagnosis of colloid cysts of the third 1981;138:385-391 ventricle. Radiology
7. Davis JM, Davis KR, Newhouse J, et al: Expanded high iodine dose in computed cranial tomography: A preliminary report. Radiology 1979;131:373-380 8. Russell DS, Rubinstein LJ: Pathology of Tumours of the Nervous System (ed 4). Baltimore: Williams and Wilkins, 1977 9. Maciewicz RJ, Davis KR: Case records of the Massachusetts General Hospital. N Engl J Med 1983;309:542549
10. Zimmerman RA, Bilaniuk LT. Wook J, et al: Computed tomography of pineal, parapineal and histologically related tumors. Radiology 1980;137:669-677 I I. Takeuchi J, Handa H, Otsuka S, et al: Neuroradiological aspects of suprasellar germinoma. Neuroradiology 1979;17:153-159 12. Murali R, Epstein F: Diagnosis and treatment of 1979;50:5 15-5 18 suprasellar arachnoid cyst. J Neurosurg