Spectrum of corpus callosum agenesis

Magnetic resonance imaging and clinical features of 16 children with agenesis of the corpus callosum are reviewed. The patients were classified in three groups. Eight children had agenesis of the corpus callosum without substantial involvement of other brain areas. This group included patients with interhemispheric cyst, lipoma, or partial agenesis (hypogenesis) of the corpus callosum. Four patients in the second group manifested severe telencephalic dysgenesis in addition to agenesis of the corpus callosum. In the third group, agenesis of the corpus callosum was a component of a syndrome in four children. The outcome was not favorable for the majority of patients, even in the first group without significant involvement of other systems. Severe handicaps with developmental delay, intellectual disability, and neurologic deficit were observed in patients with additional telencephalic dysgenesis or syndromic form of corpus callosum agenesis.     

A large interhemispheric glioependymal cyst associated with partial defect of the corpus callosum in an elderly man

Interhemispheric cysts are congenital, and usually present symptoms during childhood. However, they are occasionally detected in adults. These cystic lesions are sometimes associated with defects of the corpus callosum. Although defects of the corpus callosum by themselves do not present clinical symptoms, they are often accompanied by other brain malformations. A man in his late 60s was found dead at the scene of a fire. At autopsy, his brain weighed 1223 g and had a large interhemispheric cyst, measuring 5.5 × 4.5 × 4.0 cm in size. The cyst contained clear fluid but was not connected to the ventricular system. On slices of the cerebrum, the corpus callosum did not connect the right and left cerebral hemispheres, and the right lateral ventricle was dilated. By the existence of the cyst, compressed by the cyst, the hemispheres were displaced on either side. Histologically, the cerebral parenchyma around the cyst was slightly edematous but structurally normal. Immunohistochemically, both glial fibrillary acidic protein and podoplanin were expressed in the cystic components. Thus, the cystic lesion was diagnosed as a glioependymal cyst. In this case, because the cyst was located at the interhemispheric space between the right and left frontal lobes, the individual experienced no obvious symptoms, despite its large size. The individual's brain malformations included the partial defect of the corpus callosum and the cyst. The dilation of the right lateral ventricle was considered to result from the location of the cyst. Under the influence of the cyst, the third ventricle was displaced downward, and one or both of the interventricular foramen were obstructed. The decedent had burns over his whole body. Burns to the epiglottis and soot in the airway were also observed. Volatile hydrocarbons, such as benzene and styrene, were detected in the blood. The percentage of carboxyhemoglobin levels in a total of hemoglobin levels were 19-25%. Therefore, the individual's cause of death was established as death by fire.     

Single forebrain ventricle without prosencephaly: agenesis of the corpus callosum with dehiscent fornices

Coalescence of the cerebral ventricles with formation of a single forebrain ventricle is described in an unusual case of agenesis of the corpus callosum with dehiscent fornices and severe hydrocephalus. The cerebral hemispheres were fully cleaved. The detached fornices were widely separated from the thalami. The membrana tectoria was retroverted over the midbrain and cerebellum, where it joined the fornices and merged with a curved membranous ependymal dome which, at a great distance, circumvented the thalami as it extended toward the anterior commissure. Other anomalies included arhinencephaly, multiple subependymal heterotopias, and Dandy-Walker malformation. Similar malformations have been described as interhemispheric cysts, as (holo)prosencephaly, or as midline telencephalic dysgenesis. The basic features of prosencephaly and agenesis of the corpus callosum are reviewed and compared to the present case.     

Chudley McCullough syndrome

Background Chudley McCullough syndrome is characterized by partial agenesis of the corpus callosum, interhemispheric cyst, cerebral and cerebellar cortical dysplasias, and hydrocephalus. This syndromic form of sensorineural hearing loss is rare. Our literature search has located 13 siblings in 6 families with this syndrome. We report a case of Chudley McCullough syndrome and discuss the relevant literature. It is amply clear from the review of literature that treatment of ventricular dilatation or drainage of arachnoid cysts in these cases will not improve the sensorineural hearing loss. Case Illustration A 14-month-old female child presented with bilateral profound sensorineural hearing loss. Neuroimaging revealed partial agenesis of the corpus callosum, colpocephaly, and an interhemispheric arachnoid cyst. These associations suggested a diagnosis of Chudley McCullough syndrome.     

Infantile spasms in a patient with septo-optic dysplasia, partial agenesis of the corpus callosum and an interhemispheric cyst.

An uncommon association of infantile spasms, septo-optic dysplasia, partial agenesis of the corpus callosum and an interhemispheric cyst is described in a child. The combination of these findings has not, to our knowledge, been previously reported.     

Andermann syndrome in a Turkish patient

Agenesis of the corpus callosum with peripheral neuropathy or Andermann syndrome is an autosomal recessive disorder rarely found outside certain regions of the province of Quebec, Canada. We report a 5-year-old Turkish patient with Andermann syndrome born to consanguineous parents. She presented with diffuse hypotonic weakness, predominantly in the distal extremities, and mild mental retardation. Electromyography showed axonal-demyelinating sensorimotor neuropathy. Sural nerve biopsy was compatible with demyelinating neuropathy. Cranial magnetic resonance imaging revealed total agenesis of the corpus callosum, dilatation of the interhemispheric fissure, and enlargement of the cisterna magna. The molecular genetic analysis using microsatellite DNA markers covering the agenesis of the corpus callosum with peripheral neuropathy locus on chromosome 15q13-q15 showed that the patient is homozygous for the whole region. Our findings confirm that Andermann syndrome is a genetically homogeneous disorder.     

Transient enlargement and spontaneous regression of interhemispheric cysts--a case report

We report a 5-year-old male patient with interhemispheric cysts which showed spontaneous reduction in size. The patient was consulted to our hospital at 2 days of life for the evaluation of intracranial cysts found by fetal ultrasonography. Magnetic resonance imaging (MRI) on admission disclosed multiple cysts in the interhemispheric region and agenesis of the corpus callosum. MRI performed later disclosed the association of pachygyria and heterotopia. On follow-up MRIs, the cysts peaked in size at 5 month of age and gradually reduced thereafter. He showed transient hypertonia but had neither neurological deficits nor signs of increased intracranial pressure except transient hypertonia throughout the course. The present case is the first with interhemispheric cysts showing spontaneous reduction in size. While the present case suggested that an interhemispheric cyst dose not necessarily need a surgical treatment, and that it is difficult to determine surgical indication based on clinical manifestations.     

Mechanisms of interhemispheric transfer and patterns of cognitive function in acallosal patients of normal intelligence.

We investigated interhemispheric transfer and cognitive function in two boys with normal intelligence in whom agenesis of the corpus callosum was identified following minor head trauma. In patient 1, magnetic resonance imaging scan showed agenesis of the corpus callosum and absent anterior commissure. Results of visual interhemispheric transfer tasks suggested degradation in transfer of information to the left hemisphere. Results of a tactile interhemispheric transfer task suggested degradation of access to the right hemisphere. In patient 2, magnetic resonance imaging scan showed agenesis of the corpus callosum and enlarged anterior commissure. Results for both visual and tactile interhemispheric transfer tasks were normal. Dichotic listening tests showed a slight left ear advantage in both patients. These results support the hypothesis that hypertrophy of the anterior commissure is an important mechanism of functional compensation in agenesis of the corpus callosum. However, the relative subtlety of deficits in patient 1 and results of dichotic listening tests support use of other mechanisms as well. No consistent pattern of cognitive deficits was observed.     

Adult atretic parietal cephalocele

Atretic parietal cephalocele is a congenital anomaly of childhood with poor prognostic value. The authors report an adult with associated brain malformations (interhemispheric cyst, partial corpus callosum agenesis) - but, interestingly, without any clinical symptoms related to the entity.     

Supratentorial interhemispheric cysts associated with callosal agenesis: surgical treatment and outcome in 16 children

Cerebrospinal-fluid-filled interhemispheric cysts associated with callosal agenesis are relatively rare lesions, and have been subject to a varied and confusing terminology. From a pragmatic surgical point of view, we believe that the dorsal III ventricular cyst [35] and the giant interhemispheric cyst [23], although of different embryological origin, can be classified as one group. The most important condition that must be distinguished from interhemi-spheric cysts is the alobar form of holoprosencephaly. We describe the clinical symptomatology in 16 children who were surgically treated with a cysto-peritoneal shunt. The outcome, both neurologically and developmentally, was good in the large majority of cases, and compared favorably to similar cases in the older literature. It therefore seems reasonable, at the present state of knowledge and until further studies clarify the origin and natural history of these cysts, to treat them as early as possible in order to prevent gross developmental deficits.     

Callosal agenesis with cyst: a better understanding and new classification

OBJECTIVE: To analyze imaging studies of 25 cases of agenesis of the corpus callosum with interhemispheric cyst to assess this malformation itself and associated anomalies. METHODS: CT (6 patients) and MRI (19 patients) were retrospectively reviewed. The patients were categorized according to morphologic and clinical characteristics. RESULTS: Based on morphology, the patients were separated into two major types, each with subtypes. Type 1 cysts appear to be an extension or diverticulation of the third or lateral ventricles, whereas Type 2 are loculated and do not communicate with the ventricular system. Type 1a were associated with presumed communicating hydrocephalus but no other cerebral malformations. Type 1b were associated with hydrocephalus secondary to diencephalic malformations prohibiting egress of CSF from the third ventricle into the aqueduct of Sylvius. Type 1c were associated with small head size and apparent cerebral hemispheric dysplasia or hypoplasia. Type 2a (multiloculated cysts) were associated with no abnormalities other than callosal agenesis/hypogenesis. Type 2b were associated with deficiencies of the falx cerebri, subependymal heterotopia, and polymicrogyria (and were almost all in patients diagnosed with Aicardi syndrome). Type 2c were associated with subcortical heterotopia. Type 2d consists of interhemispheric arachnoid cysts. Other than those with Type 2b cysts, gender predominance was overwhelmingly male. CONCLUSION: Agenesis of the corpus callosum with interhemispheric cyst appears to consist of a heterogeneous group of disorders that have in common callosal agenesis and extraparenchymal cysts, both of which are among the commonest CNS malformations. This article proposes a classification system, based primarily on morphology, by which this complex group of disorders might begin to be better understood.     

Study of cerebral circulation and cerebrospinal fluid dynamics in a patient with agenesis of the corpus callosum using 123I-IMP SPECT and cine-mode MRI

A right-handed, 77-year-old man, complaining of dizziness, was diagnosed as agenesis of the corpus callosum (ACC) by MRI, which demonstrated a complete defect of the corpus callosum (CC) with symmetrical enlargement of the posterior horns of the bilateral ventricles (colpocephy) and focal hypo-plasticity of the frontal lobes. Neurological examination revealed only mild impairment of mental function and poor transfer of tactile form-board learning from the right hand to the left hand. As to the cerebral circulation detected by 123I-IMP SPECT, isotope distribution corresponded to the MRI brain images, though the defects were clearly seen on the medial surfaces of the bilateral frontal lobes, so interhemispheric fissure seemed to be opened widely. IV-DSA revealed hypo-vascularity in the anterior territory of the anterior cerebral arteries. These findings suggested that this localized defect was due to hypo-vascularity and focal hypo-plasticity of the frontal lobes. On the other hand, cine-mode MRI findings that no signal-void phenomenon was found between the third ventricle and the longitudinal fissure indicated no shunt in cerebrospinal fluid.     

Bilateral field advantage and evoked potential interhemispheric transmission in commissurotomy and callosal agenesis.

The role of the corpus callosum versus other cerebral commissures in the interhemispheric integration of visual information was studied in four individuals with complete agenesis of the corpus callosum, two individuals with partial agenesis, one total commissurotomy patient, and normal individuals. Evoked potential (EP) indices of interhemispheric transmission of visual sensory responses were observed during matching of unilateral and bilateral visual field letters and patterns. Neither the commissurotomy nor any of the acallosal patients had ipsilateral hemisphere visual EPs (P1 and N1), demonstrating that the posterior callosum is necessary for interhemispheric transmission of these components of visual evoked potentials. While the commissurotomy patient could not compare bilaterally presented letters, the anterior commissure of the acallosal patients appeared to be sufficient for interhemispheric comparison of single letters. However, bilateral comparison of more complex visual patterns resulted in considerable difficulty for complete agenesis patients, while comparison of patterns was more nearly normal when anterior callosal fibers were present (partial agenesis).     

Prenatal diagnosed cyst of the quadrigeminal cistern in Aicardi syndrome

Aicardi syndrome is an X-linked dominant disorder characterized by the pathognonomic association of three clinical signs: agenesis of the corpus callosum, infantile spasms, and chorioretinal lacunae. This is a severe syndrome with an estimated survival rate of 76% at 6 years and 40% at 14 years and a maximum developmental level like a 12-month-old baby in 91% of cases. We illustrate a case of Aicardi syndrome with bilateral, small chorioretinal lacunae, infantile spasms with a typical hypsarrhythmia, defects of thoracic vertebra and bilateral absence of the12th rib associated with an arachnoid cyst of the quadrigeminal cistern, and presence of the corpus callosum with a favorable outcome.     

Empty sella syndrome in nevoid basal cell carcinoma syndrome

We reported the magnetic resonance imaging of four young patients (13 to 19 years) with nevoid basal cell carcinoma syndrome (NBCCS), which showed empty sella, agenesis of the corpus callosum and empty sella, an interhemispheric lipoma with callosal dysgenesis, and an arachnoid cyst in the posterior fossa, respectively. Calcification of the diaphragma sellae, which is a protective barrier against the pulsating action of the cerebrospinal fluid, may cause the empty sella in NBCCS.     

Posttraumatic intraventricular arachnoid cyst accompanied by pseudomeningoencephalocele in a child

Growing skull fracture (GSF) is a rare complication of head trauma. A posttraumatic intraventricular arachnoid cyst (AC), neither isolated nor accompanied by a GSF has not been reported previously. A seven-year-old girl was admitted after a severe head injury with a separated right parieto-occipital fracture and contusion. She responded well to conservative therapy. Seven weeks after discharge, she was re-admitted with a large parieto-occipital pseudomeningoencephalocele due to herniation of cerebrospinal fluid and neural tissue to the subgaleal space through the widened fracture defect, an extra-axial cyst at the posterior interhemispheric space and an intraventricular cystic mass. She underwent open surgery, and the intraventricular cystic mass was totally removed. The histological findings were consistent with an AC. One week after dural repair, hydrocephalus developed, and a ventriculo-peritoneal shunt was inserted. She did well during two-year follow-up. The present case is unique as an intraventricular AC following head trauma. When an intraventricular cystic lesion is encountered after severe head trauma, the possibility of an AC should be considered; especially with neighboring contused neural tissue and leptomeningeal cyst formation.     

Temporary and permanent signs of interhemispheric disconnection after traumatic brain injury

The corpus callosum is frequently damaged by closed head traumas, and the resulting deficits of interhemispheric communication may vary according to the specific position of the lesion within the corpus callosum. This paper describes a single case who suffered a severe traumatic brain injury resulting in a lesion of the posterior body of the corpus callosum. Among the classical symptoms of interhemispheric disconnection, left hand anomia, left upper limb ideomotor dyspraxia, left visual field dyslexia and dysnomia, and left ear suppression in a dichotic listening task were observed shortly after the injury but recovered completely or almost completely with the passage of time. The only symptom of interhemispheric disconnection which was found to persist more than 4 years after the injury was an abnormal prolongation of the crossed-uncrossed difference in a simple visuomotor reaction time task. This prolongation was comparable with that observed in subjects with complete callosal lesions or agenesis. The results suggest that the posterior body of the corpus callosum may be an obligatory interhemispheric communication channel for mediating fast visuo-motor responses. The transient nature of other symptoms of interhemispheric disconnection suggests a relatively wide dispersion of fibers with different functions through the callosal body, such that parts of them can survive a restricted lesion and allow functional recovery of hemispheric interactions. An assessment of the evolution in time of symptoms of interhemispheric disconnection following restricted callosal lesions may reveal fine and coarse features of the anatomo-functional topography of the corpus callosum.     

Interhemispheric visual information transfer in callosal agenesis

It has been well established that acquired lesions of the corpus callosum such as surgical section bring about disturbances of interhemispheric transfer of visual information. In contrast, patients with callosal agenesis do not display these specific deficits. The mechanisms of this compensation have been postulated as follows; (1) bilateral development of language function, (2) exploitation of extracallosal commissure fibers such as the anterior commissure. Several studies have reported, however, minor disturbances of interhemispheric visual transfer in callosal agenesis, such as less efficient interhemispheric transfer of complex visual stimuli (Gott & Saul, 1978), slower reaction time in interhemispheric comparison of visual stimuli (Sauerwein & Lassonde, 1983), or deficits in spatial localization in the right hemi-field (Martin, 1985). In order to settle these issues, we have administered four kinds of tachistoscopic visual recognition tests on 4 patients with complete agenesis of the corpus callosum confirmed by magnetic resonance imaging (MRI). This technique enabled us to see the mid-sagittal plane of the corpus callosum and diagnose its total absence with much higher certainty and precision than previous studies employing computed tomography (CT) or pneumoencephalography. Case 1: A 41-year-old right-handed man visited us because of recurrent numbness in the four extremities. Neurological examination revealed no abnormalities. MRI has confirmed that the corpus callosum was totally lacking, and that the anterior commissure was normally visualized. Case 2: A 31-year-old right-handed man was referred to us for the treatment of partial complex seizure. Total agenesis and lipoma of the corpus callosum was diagnosed by MRI and reconstructed sagittal view of CT scan.(ABSTRACT TRUNCATED AT 250 WORDS)     

A case of agenesis of the corpus callosum accompanied by a ruptured azygos anterior cerebral artery aneurysm and lipoma--a case report

A 53-year-old woman suffered from sudden onset of severe headache on February 28 in 1982. She was admitted to our hospital soon after onset. On admission, she had a severe headache and nausea, and her consciousness was drowsy. CT scan showed a marked subarachnoid hemorrhage with intracerebral and intraventricular hematoma, a separation of the lateral ventricles with enlargement of posterior horns, and deformity of anterior horn. By these findings, the patient was diagnosed as an agenesis of the corpus callosum with subarachnoid hemorrhage. Left carotid arteriogram revealed an azygos anterior cerebral artery and an aneurysm at the terminal portion of this artery. Surgery was performed on the 24 th day after subarachnoid hemorrhage. Operative finding revealed a little finger's head-sized tumor was situated over the right frontobasal artery. An azygos anterior cerebral artery aneurysm was clipped and tumor was removed. Pathological diagnosis of the tumor was a lipoma. Namely, she had an agenesis of the corpus callosum, an azygos anterior cerebral artery, an aneurysm and a lipoma. There are some reports in which an agenesis of the corpus callosum is accompanied with a lipoma and an azygos anterior cerebral artery is accompanied with an aneurysm. But a case of agenesis of the corpus callosum with an azygos anterior cerebral artery was rarely reported. So this rare case with these anomalies was reported and pathogenesis about the development of 4 anomalies was also discussed.