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Schizencephaly
JOURNAL
OF COMPUTED
TOMOGRAPHY
1983;7:135-139
SCHIZENCEPHALY J. POWELL CHARLES
WILLIAMS, L. DUNAWAY,
C. PHILLIP AND
BLALOCK,
ELIAS
Schizencephaly means clefts in the brain and refers to that condition of dysmorphogenesis in which there are bilateral, usually symmetrical, clefts in the region of the central sulcus. This condition is readily demonstrated by computed tomography and is associated with severe mental retardation. We add three case studies to those previously recorded in the literature. KEY WORDS:
Schizencephaly; Bilateral hemispheric defects; Polymicrogyria; Mental retardation; Absent septum pellucidum
The term schizencephaly is derived from the Greek schiz, meaning divided, and encephaly, referring to the brain. The term was first coined by Yakovlev and Wadsworth (1, 2) in 1946 and was applied to that condition in which clefts, usually symmetrical, are present, usually in both cerebral hemispheres. A number of cases have been reported in the literature since that time, but only one since the advent of computed tomography (CT] (3). We present three additional cases, all studied by CT.
CASE REPORTS Case
1
The patient, a g-year-old girl, was the product of a full-term, uncomplicated pregancy. The mother was 19 years old, gravida 1, para 0, abortus 0, and has
From the Department of Radiolow, University of South Alabama College of-Medicine, Mobile, Alabama. _ Address reprint requests to: J. Powell Williams, MD, Department of Radiology, University of South Alabama College of Medicine, 2451 Fillingim Street, Mobile, Alabama 36617. Accepted October 1982. 0 1983 by Elswier Science Publishing Co., Inc. 52 Vanderbilt Ave., New York, NY 10017 0149-936x!83i020135-05$3.00
G. CHALHUB
had no subsequent pregnancies. The child appeared normal at birth and developed normally until the age of 4 months. She was evaluated at the age of 1 year because of delay in mental and physical development. At that time she was thought to have cerebral palsy. Evaluation at 6 years of age revealed that the patient was aware of her surroundings, However, she was not able to pull herself up and had little, if any, head control. Cranial nerves II-XII were intact. The child had 3 + deep tendon reflexes bilaterally, normal Babinski’s sign, and there was an unsustained clonus of the ankles. The head circumference was below normal in size. The overall clinical impression was that of a severely retarded child who had not achieved the usual milestones after 4 months of age. A CT examination with and without contrast-medium enhancement was performed on an EM1 1005 scanner. The scan showed absence of the septum pellucidurn but a normal corpus callosum (Figure 1A). There was a cleft that had a CT attenuation equal to that of cerebrospinal fluid extending from the lateral aspect of the midbody of the left lateral ventricle to the surface of the brain (Figure 1B). On the right, there was a beak-like deformity that extended from a similar area in the body of the lateral ventricle but did not reach through the cerebral mantle. The subarachnoid cisterns and the third and fourth ventricles appeared normal. The density of cerebral tissue was normal and no other abnormality was demonstrated. A scan following injection of intravenous contrast medium added no additional information.
Case 2 The patient was an ll-month-old girl who had been delivered by cesarean section. The mother was gravida 8, para 8, abortus 0. The pregnancy was complicated by high blood pressure. The patient was evaluated for developmental delay. At the age
136
WILLIAMS ET AL.
FIGURE 1A. An axial CT scan through the level of the frontal horns and third ventricle shows absence of the septum pellucidum. Some asymmetry of the remainder of the lateral ventricles is noted but the ventricles are normal in size at this level.
of 3 months, the mother noticed that the child constantly kept her lower extremities in a scissor-like position. She was unable to sit up, turn over, crawl, or reach for objects. Physical examination showed the child to be below the fifth percentile for height and size of head circumference. Reflexes were 3 + in the lower extremities with a 2-beat clonus in the feet. There was spastic rigidity of the upper extremities as well. The cranial nerves were normal. The overall clinical impression was that of profound developmental delay with spasticity of the extremities. CT examination was performed on a Picker Synerview 600 scanner without intravenous contrast enhancement. There was absence of the septum pellucidum, although the corpus callosum appeared to be intact (Figure 2A). The anterior portions of the lateral ventricles were somewhat enlarged, but the third and fourth ventricle were normal in size.
THE JOURNAL OF COMPUTEDTOMOGRAPHYVOL.
7
NO. 2
1B. At a somewhat higher level, a cleft can be seen extending laterally from the midportion of the body of the left lateral ventricle to the cortical surface of the hemisphere. On the right side, a beak-like deformity of the ventricle is noted, but no cleft can be demonstrated extending through the hemisphere to the surface. FIGURE
Clefts extending from the surface of each lateral ventricle to the surface of the brain in the region of the central sulcus were demonstrated bilaterally (Figure 2B). These clefts were relatively symmetrical and appeared to communicate between the subarachnoid space and the ventricles bilaterally. There was also slight widening of the interhemispheric fissure anteriorly and the cisterna magna was prominent. Other cortical sulci appeared to be within normal limits. A coronal reformatted image (Figure 2C) was also obtained and showed the clefts extending from the superior lateral aspect of each lateral ventricle to the cortical surface. Case
3
This 3-year-old boy was being evaluated prior to adoption. The 16-year-old mother was gravida I, para 1, abortus 0. The child weighed 4 lb, 12 oz at
FIGURE 2A. A CT scan through the frontal horns of the lateral ventricles shows absence of the septum pellucidum. The frontal horns are somewhat enlarged, with the left being larger than the right, but the third ventricle is normal in size.
FIGURE 2C. A coronally reformatted image shows somewhat enlarged lateral ventricles with no septum pellucidum demonstrated. A normal-sized third ventricle is seen. Bilateral clefts extending from the superior lateral aspect of the two ventricles to the cortical surface are demonstrated.
FIGURE ZB. A section at the level off the upper part of bodies of the lateral ventricles shows #relatively symmetrical clefts extending from the ventricle to the cortical surface bilaterally. Some atrophy of the frontal poles is also noted.
138
WILLIAMS ET AL.
birth following a 32 week gestation and an uneventful pregnancy. There was no family history of neurologic disease or mental retardation. Initial Apgar scores were 9 and 9 at 1 and 5 minutes, respectively, and the early neonatal course was uneventful. Subsequently the child did poorly and was noted to have decreased head control and inability to roll over. Physical examination demonstrated a normally shaped small head. No bruits were heard over the head or neck. Neurologic examination demonstrated an alert child. Pipils were equal and reactive to light and accommodation. Extraocular movements were full, and the discs and retina were normal. The child did fix but did not follow moving objects in his field of view. Cranial nerves were normal. Motor system evaluation showed the head to have a slight tilt to the left, increased muscle tone was present diffusely, and reflexes were also increased. No ataxia was present and sensory examination was normal. An electroencephalogram was moderately abnormal due to slow wave activity and presence of paroxysmal activity, predominantly from the right hemisphere. Urine and blood chemistries, as well as thyroid function studies, were normal. - A CT examination was performed on an EM1 1005 scanner without intravenous contrast-medium enhancement (Figure 3). The scan demonstrated absence of the septum pellucidum and large defects that extended from the ventricle to the calvarium involving much of the frontoparietal areas of the cerebrum bilaterally. Although the corpus callosum was not readily identifiable, other features of agenesis, such as an elevated third ventricle, were not demonstrated. DISCUSSION
The original description of schizencephaly by Yakovlev and Wadsworth (1,2) attempted to differentiate this condition from porencephaly. They felt that porencephaly represented an encephaloclastic condition, with destruction of previously existing brain. Schizencephaly is a failure of primary development of this portion of the brain. The defects are usually symmetrical and occur in the region of the central sulcus. The width of the clefts vary, probably depending on coexistant hydrocephalus. Absence of the septum pellucidum is common and agenesis of the corpus callosum may also be present (4). Yakovlev and Wadsworth also point out the occurrence of polymicrogyria, which may be present in case 2.
1THE JOURNAL OF COMPUTED TOMOGRAPHY VOL.
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NO. 2
FIGURE 3.An axial CT scan shows large bilateral defects extending from the ventricles to the surface of the brain bilaterally. The third and fourth ventricles were normal in size.
Review of the literature shows there to be considerable variation in the size and symmetry of the actual clefts, as demonstrated with pneumoencephalography or at autopsy (5-10). The article by Harwood-Nash (3) shows a CT scan, described as schizencephaly, showing only a cleft running obliquely in one cerebral hemisphere. Although this is certainly a cleft in the brain, it does not fit the classical description of bilateral symmetrical clefts; nor does case 1,which is quite asymmetric. Case 2 does fit the classical description, but case 3 shows very large defects bilaterally which might be interpreted as porencephaly. If porencephaly represents destruction of preexisting brain, one would have to suppose bilateral symmetrical infarcts or some traumatic injury. As noted in the literature (2, 4, 5), the size of the cleft may vary due to superimposed hydrocephalus. It can probably also vary depending on the extent of the insult preventing normal development. This is probably the circum-
139
SCHIZENCEPHALY
MAY 1983
stance in case 3. This patient had a third and fourth ventricles of normal size. Also, overall head size was below normal, indicating no coexisting hydrocephalus. There was considerable variation in the physical condition of the patients. The one finding common to all cases was severe mental retardation, and demonstration of this anomaly at an early age is a grave prognostic indicator. Computed tomography offers a simple means of diagnosing this anomaly. This condition is generally agreed be a true dysmorphogenesis, with the insult occurring in the second month of gestation before the cerebral hemispheres divide into two separate vesicles, thereby accounting for the bilateral symmetry of the defect. REFERENCES
8. Dekaban
A: Large defects in the cerebral hemispheres associated with cortical dysgenesis. J Neuropathol Exp Neurol 24:512-530,1965
9. Lindenberg R, Swanson 90:839-850,1967
10. Muir CS: Hydranencephaly Child 34231-246, 1959
hydranencephaly.
and allied
disorders.
Brain
Am J Dis
CONTINUING MEDICAL EDUCATION QUESTIONS 1. Schizencephaly
is defined as: childhood form of schizophrenia. b. Symmetrical clefts in the brain often associated with mental retardation. c. An encephaloclastic condition af the brain, according to Yakovlev. d. Absence of the septum pellucidum.
a.
A
2. Encephaloclastic
PI, Wadsworth RC: Schizencephalies: A study of the congenital clefts in the cerebral mantle. I. Clefts with fused tips. J Neuropathol Exp Neurol 5:116-130, 1946
P: Infantile
refers to:
1. Yakovlev
a.
2. Yakovlev PI, Wadsworth RC: Schizencephalies: A study of the congenital clefts in the cerebral mantle. II. Clefts with hydrocephelus and tips separated. J Neuropathol Exp Neurol 5:169-206, 1946
b. Failure of development of a portion of the cerebral cortex. c. A fibrotic reaction of the glial elements to brain injury. d. None of the above.
3. Harwood-Nash and computed 1977
DC: Congenital craniocerebral abnormalities tomography. Semin Roentgen01 12:39-51,
4. Page LD, Brown cephaly: A clinical 1975
SB, Gargano FP, Shortz RW: Schizenstudy and review. Child Brain 1:348-358,
5. Bubis JJ, Zandau WM: Agenesis of pyramidal tracts associated with schizencephalic clefts in rolandic cortex. Neurology 14:821-824,1964 6. Christensen E, Moller JE: Morphology of some developmental abnormalities of the central nervous system. Acta Neurol Stand 43(suppl):Zl-30, 1967 7. Cohn R, Neuman MA: Porencephaly, a clinicopathologic study. J Neuropathol Exp Neurol 5:257-270, 1946
Destruction
or absorption
of brain
3. Schizencephaly is characterized by: a. Mental retardation. b. Spastic paraplegia. c. Small head circumference. d. Bilateral brain clefts, classically. e. All of the above. 4. In schizencephaly, hydrocephalus: a. Is the presumed etiological factor. b. Is always associated. c. Can be associated. d. Develops secondarily in all cases. e. None of the above.
substance.
OF COMPUTED
TOMOGRAPHY
1983;7:135-139
SCHIZENCEPHALY J. POWELL CHARLES
WILLIAMS, L. DUNAWAY,
C. PHILLIP AND
BLALOCK,
ELIAS
Schizencephaly means clefts in the brain and refers to that condition of dysmorphogenesis in which there are bilateral, usually symmetrical, clefts in the region of the central sulcus. This condition is readily demonstrated by computed tomography and is associated with severe mental retardation. We add three case studies to those previously recorded in the literature. KEY WORDS:
Schizencephaly; Bilateral hemispheric defects; Polymicrogyria; Mental retardation; Absent septum pellucidum
The term schizencephaly is derived from the Greek schiz, meaning divided, and encephaly, referring to the brain. The term was first coined by Yakovlev and Wadsworth (1, 2) in 1946 and was applied to that condition in which clefts, usually symmetrical, are present, usually in both cerebral hemispheres. A number of cases have been reported in the literature since that time, but only one since the advent of computed tomography (CT] (3). We present three additional cases, all studied by CT.
CASE REPORTS Case
1
The patient, a g-year-old girl, was the product of a full-term, uncomplicated pregancy. The mother was 19 years old, gravida 1, para 0, abortus 0, and has
From the Department of Radiolow, University of South Alabama College of-Medicine, Mobile, Alabama. _ Address reprint requests to: J. Powell Williams, MD, Department of Radiology, University of South Alabama College of Medicine, 2451 Fillingim Street, Mobile, Alabama 36617. Accepted October 1982. 0 1983 by Elswier Science Publishing Co., Inc. 52 Vanderbilt Ave., New York, NY 10017 0149-936x!83i020135-05$3.00
G. CHALHUB
had no subsequent pregnancies. The child appeared normal at birth and developed normally until the age of 4 months. She was evaluated at the age of 1 year because of delay in mental and physical development. At that time she was thought to have cerebral palsy. Evaluation at 6 years of age revealed that the patient was aware of her surroundings, However, she was not able to pull herself up and had little, if any, head control. Cranial nerves II-XII were intact. The child had 3 + deep tendon reflexes bilaterally, normal Babinski’s sign, and there was an unsustained clonus of the ankles. The head circumference was below normal in size. The overall clinical impression was that of a severely retarded child who had not achieved the usual milestones after 4 months of age. A CT examination with and without contrast-medium enhancement was performed on an EM1 1005 scanner. The scan showed absence of the septum pellucidurn but a normal corpus callosum (Figure 1A). There was a cleft that had a CT attenuation equal to that of cerebrospinal fluid extending from the lateral aspect of the midbody of the left lateral ventricle to the surface of the brain (Figure 1B). On the right, there was a beak-like deformity that extended from a similar area in the body of the lateral ventricle but did not reach through the cerebral mantle. The subarachnoid cisterns and the third and fourth ventricles appeared normal. The density of cerebral tissue was normal and no other abnormality was demonstrated. A scan following injection of intravenous contrast medium added no additional information.
Case 2 The patient was an ll-month-old girl who had been delivered by cesarean section. The mother was gravida 8, para 8, abortus 0. The pregnancy was complicated by high blood pressure. The patient was evaluated for developmental delay. At the age
136
WILLIAMS ET AL.
FIGURE 1A. An axial CT scan through the level of the frontal horns and third ventricle shows absence of the septum pellucidum. Some asymmetry of the remainder of the lateral ventricles is noted but the ventricles are normal in size at this level.
of 3 months, the mother noticed that the child constantly kept her lower extremities in a scissor-like position. She was unable to sit up, turn over, crawl, or reach for objects. Physical examination showed the child to be below the fifth percentile for height and size of head circumference. Reflexes were 3 + in the lower extremities with a 2-beat clonus in the feet. There was spastic rigidity of the upper extremities as well. The cranial nerves were normal. The overall clinical impression was that of profound developmental delay with spasticity of the extremities. CT examination was performed on a Picker Synerview 600 scanner without intravenous contrast enhancement. There was absence of the septum pellucidum, although the corpus callosum appeared to be intact (Figure 2A). The anterior portions of the lateral ventricles were somewhat enlarged, but the third and fourth ventricle were normal in size.
THE JOURNAL OF COMPUTEDTOMOGRAPHYVOL.
7
NO. 2
1B. At a somewhat higher level, a cleft can be seen extending laterally from the midportion of the body of the left lateral ventricle to the cortical surface of the hemisphere. On the right side, a beak-like deformity of the ventricle is noted, but no cleft can be demonstrated extending through the hemisphere to the surface. FIGURE
Clefts extending from the surface of each lateral ventricle to the surface of the brain in the region of the central sulcus were demonstrated bilaterally (Figure 2B). These clefts were relatively symmetrical and appeared to communicate between the subarachnoid space and the ventricles bilaterally. There was also slight widening of the interhemispheric fissure anteriorly and the cisterna magna was prominent. Other cortical sulci appeared to be within normal limits. A coronal reformatted image (Figure 2C) was also obtained and showed the clefts extending from the superior lateral aspect of each lateral ventricle to the cortical surface. Case
3
This 3-year-old boy was being evaluated prior to adoption. The 16-year-old mother was gravida I, para 1, abortus 0. The child weighed 4 lb, 12 oz at
FIGURE 2A. A CT scan through the frontal horns of the lateral ventricles shows absence of the septum pellucidum. The frontal horns are somewhat enlarged, with the left being larger than the right, but the third ventricle is normal in size.
FIGURE 2C. A coronally reformatted image shows somewhat enlarged lateral ventricles with no septum pellucidum demonstrated. A normal-sized third ventricle is seen. Bilateral clefts extending from the superior lateral aspect of the two ventricles to the cortical surface are demonstrated.
FIGURE ZB. A section at the level off the upper part of bodies of the lateral ventricles shows #relatively symmetrical clefts extending from the ventricle to the cortical surface bilaterally. Some atrophy of the frontal poles is also noted.
138
WILLIAMS ET AL.
birth following a 32 week gestation and an uneventful pregnancy. There was no family history of neurologic disease or mental retardation. Initial Apgar scores were 9 and 9 at 1 and 5 minutes, respectively, and the early neonatal course was uneventful. Subsequently the child did poorly and was noted to have decreased head control and inability to roll over. Physical examination demonstrated a normally shaped small head. No bruits were heard over the head or neck. Neurologic examination demonstrated an alert child. Pipils were equal and reactive to light and accommodation. Extraocular movements were full, and the discs and retina were normal. The child did fix but did not follow moving objects in his field of view. Cranial nerves were normal. Motor system evaluation showed the head to have a slight tilt to the left, increased muscle tone was present diffusely, and reflexes were also increased. No ataxia was present and sensory examination was normal. An electroencephalogram was moderately abnormal due to slow wave activity and presence of paroxysmal activity, predominantly from the right hemisphere. Urine and blood chemistries, as well as thyroid function studies, were normal. - A CT examination was performed on an EM1 1005 scanner without intravenous contrast-medium enhancement (Figure 3). The scan demonstrated absence of the septum pellucidum and large defects that extended from the ventricle to the calvarium involving much of the frontoparietal areas of the cerebrum bilaterally. Although the corpus callosum was not readily identifiable, other features of agenesis, such as an elevated third ventricle, were not demonstrated. DISCUSSION
The original description of schizencephaly by Yakovlev and Wadsworth (1,2) attempted to differentiate this condition from porencephaly. They felt that porencephaly represented an encephaloclastic condition, with destruction of previously existing brain. Schizencephaly is a failure of primary development of this portion of the brain. The defects are usually symmetrical and occur in the region of the central sulcus. The width of the clefts vary, probably depending on coexistant hydrocephalus. Absence of the septum pellucidum is common and agenesis of the corpus callosum may also be present (4). Yakovlev and Wadsworth also point out the occurrence of polymicrogyria, which may be present in case 2.
1THE JOURNAL OF COMPUTED TOMOGRAPHY VOL.
7
NO. 2
FIGURE 3.An axial CT scan shows large bilateral defects extending from the ventricles to the surface of the brain bilaterally. The third and fourth ventricles were normal in size.
Review of the literature shows there to be considerable variation in the size and symmetry of the actual clefts, as demonstrated with pneumoencephalography or at autopsy (5-10). The article by Harwood-Nash (3) shows a CT scan, described as schizencephaly, showing only a cleft running obliquely in one cerebral hemisphere. Although this is certainly a cleft in the brain, it does not fit the classical description of bilateral symmetrical clefts; nor does case 1,which is quite asymmetric. Case 2 does fit the classical description, but case 3 shows very large defects bilaterally which might be interpreted as porencephaly. If porencephaly represents destruction of preexisting brain, one would have to suppose bilateral symmetrical infarcts or some traumatic injury. As noted in the literature (2, 4, 5), the size of the cleft may vary due to superimposed hydrocephalus. It can probably also vary depending on the extent of the insult preventing normal development. This is probably the circum-
139
SCHIZENCEPHALY
MAY 1983
stance in case 3. This patient had a third and fourth ventricles of normal size. Also, overall head size was below normal, indicating no coexisting hydrocephalus. There was considerable variation in the physical condition of the patients. The one finding common to all cases was severe mental retardation, and demonstration of this anomaly at an early age is a grave prognostic indicator. Computed tomography offers a simple means of diagnosing this anomaly. This condition is generally agreed be a true dysmorphogenesis, with the insult occurring in the second month of gestation before the cerebral hemispheres divide into two separate vesicles, thereby accounting for the bilateral symmetry of the defect. REFERENCES
8. Dekaban
A: Large defects in the cerebral hemispheres associated with cortical dysgenesis. J Neuropathol Exp Neurol 24:512-530,1965
9. Lindenberg R, Swanson 90:839-850,1967
10. Muir CS: Hydranencephaly Child 34231-246, 1959
hydranencephaly.
and allied
disorders.
Brain
Am J Dis
CONTINUING MEDICAL EDUCATION QUESTIONS 1. Schizencephaly
is defined as: childhood form of schizophrenia. b. Symmetrical clefts in the brain often associated with mental retardation. c. An encephaloclastic condition af the brain, according to Yakovlev. d. Absence of the septum pellucidum.
a.
A
2. Encephaloclastic
PI, Wadsworth RC: Schizencephalies: A study of the congenital clefts in the cerebral mantle. I. Clefts with fused tips. J Neuropathol Exp Neurol 5:116-130, 1946
P: Infantile
refers to:
1. Yakovlev
a.
2. Yakovlev PI, Wadsworth RC: Schizencephalies: A study of the congenital clefts in the cerebral mantle. II. Clefts with hydrocephelus and tips separated. J Neuropathol Exp Neurol 5:169-206, 1946
b. Failure of development of a portion of the cerebral cortex. c. A fibrotic reaction of the glial elements to brain injury. d. None of the above.
3. Harwood-Nash and computed 1977
DC: Congenital craniocerebral abnormalities tomography. Semin Roentgen01 12:39-51,
4. Page LD, Brown cephaly: A clinical 1975
SB, Gargano FP, Shortz RW: Schizenstudy and review. Child Brain 1:348-358,
5. Bubis JJ, Zandau WM: Agenesis of pyramidal tracts associated with schizencephalic clefts in rolandic cortex. Neurology 14:821-824,1964 6. Christensen E, Moller JE: Morphology of some developmental abnormalities of the central nervous system. Acta Neurol Stand 43(suppl):Zl-30, 1967 7. Cohn R, Neuman MA: Porencephaly, a clinicopathologic study. J Neuropathol Exp Neurol 5:257-270, 1946
Destruction
or absorption
of brain
3. Schizencephaly is characterized by: a. Mental retardation. b. Spastic paraplegia. c. Small head circumference. d. Bilateral brain clefts, classically. e. All of the above. 4. In schizencephaly, hydrocephalus: a. Is the presumed etiological factor. b. Is always associated. c. Can be associated. d. Develops secondarily in all cases. e. None of the above.
substance.