sincipital encephaloceles , also called frontal or anterior encephaloceles , are rare neural tube defects and are more common in south and southeast asian populations . in children with sincipital encephaloceles there are often significant associated intracranial anomalies , including intracranial cysts , complete / partial corpus callosal agenesis , interhemispheric lipomas , facial clefts , and migrational anomalies . occipital encephaloceles may be associated with chiari or dandy - walker malformations and callosal or migrational anomalies . it is reported that younger siblings of patients affected with encephaloceles have up to 6% risk of a congenital central nervous system abnormality . after approval from the institutional ethics review committee , a hospital - based cross - sectional study was conducted over 8 years from june 2007 to may 2015 on 28 patients in the departments of radiodiagnosis and pediatric surgery in a tertiary care hospital . the study comprised of outpatients and in patients , of both sexes presenting with sincipital encephaloceles . patients were only allowed plain water preceding the imaging so as to keep the patient ready for sedation / anesthesia if needed . the patients were evaluated by either computed tomography ( ct ) or magnetic resonance imaging ( mri ) whichever was feasible . the ct scanner used in this study was siemens somatom spirit dual slice ct scanner ( siemens healthcare , erlangen , germany ) . unenhanced ct scans of head and faciomaxillary region were obtained in all patients . scanning parameters used were spiral mode with slice thickness of 6 mm and collimation 6 mm  2.5 mm , pitch : 1.4 ; kvp : 130 ; mas : 80 . mri imaging was performed with a 1.5-t superconducting magnet system 1.5 tesla siemens magnetom avanto b15 system ( siemens healthcare , erlangen , germany ) using a transmit / receive body coil with a 15-mt / m gradient . the imaging parameters were t1 , t2 , and fluid - attenuated inversion recovery ( flair ) sequences obtained in all three planes : axial , coronal and sagittal . parameters for t1-wi ( t1-weighted image ) : 400600/15 ( repetition time ms / echo time ms ) , 220240-mm field of view , 256  192 matrix , and slice thickness of 5 mm with a gap of 1 mm . parameters for t2-wi : 3200/428 ( repetition time ms / echo time ms ) , 256-mm field of view , 256  256 matrix , and slice thickness of 5 mm with a gap of 1 mm . parameters for flair : 10,000/70130 ( repetition time ms / echo time ms ) , 240-mm field of view , 256  192 matrix , and slice thickness of 5 mm with a gap of 1 mm . the areas of interest in the study were type of encephalocele , its contents , extracranial extension and effect on adjacent structures and to look for associated brain malformations . after approval from the institutional ethics review committee , a hospital - based cross - sectional study was conducted over 8 years from june 2007 to may 2015 on 28 patients in the departments of radiodiagnosis and pediatric surgery in a tertiary care hospital . the study comprised of outpatients and in patients , of both sexes presenting with sincipital encephaloceles . patients were only allowed plain water preceding the imaging so as to keep the patient ready for sedation / anesthesia if needed . the patients were evaluated by either computed tomography ( ct ) or magnetic resonance imaging ( mri ) whichever was feasible . the ct scanner used in this study was siemens somatom spirit dual slice ct scanner ( siemens healthcare , erlangen , germany ) . scanning parameters used were spiral mode with slice thickness of 6 mm and collimation 6 mm  2.5 mm , pitch : 1.4 ; kvp : 130 ; mas : 80 . mri imaging was performed with a 1.5-t superconducting magnet system 1.5 tesla siemens magnetom avanto b15 system ( siemens healthcare , erlangen , germany ) using a transmit / receive body coil with a 15-mt / m gradient . the imaging parameters were t1 , t2 , and fluid - attenuated inversion recovery ( flair ) sequences obtained in all three planes : axial , coronal and sagittal . parameters for t1-wi ( t1-weighted image ) : 400600/15 ( repetition time ms / echo time ms ) , 220240-mm field of view , 256  192 matrix , and slice thickness of 5 mm with a gap of 1 mm . parameters for t2-wi : 3200/428 ( repetition time ms / echo time ms ) , 256-mm field of view , 256  256 matrix , and slice thickness of 5 mm with a gap of 1 mm . parameters for flair : 10,000/70130 ( repetition time ms / echo time ms ) , 240-mm field of view , 256  192 matrix , and slice thickness of 5 mm with a gap of 1 mm . the areas of interest in the study were type of encephalocele , its contents , extracranial extension and effect on adjacent structures and to look for associated brain malformations . fifty percent of the patients presented before the age of 3 years , with the youngest presenting on day 7 . rest of the patients ( 42% ) presented between 3 and 10 years of age . our study did not show any gender predominance , with both males and females being affected equally . nasofrontal encephalocele was the most common type , seen in 13 ( 46.4% ) patients . the naso - orbital and the combined type were the least common with 4 ( 14.2% ) patients each . two patients had evidence of herniation of lateral ventricle along with brain tissue through the cranium into the encephalocele sac [ table 1 ] . type of sincipital encephaloceles corpus callosal agenesis with colpocephaly was the most common associated malformation in our study [ table 2 ] . 6/10 archnoid cysts were hemispheric , 4/10 were inter hemispheric and 2/10 were located in posterior fossa . associated brain malformations seven patients had evidence of hydrocephalus , of which five cases were due to the obstruction by large arachnoid cysts and two cases were due to aqueduct stenosis . subdural collection was noted in 6 patients . in 4 patients it was subdural csf collection due to hyperfunctioning of shunts and in 2 patients it was blood due to rupture of bridging cortical veins . of these 6 patients , ventriculoperitoneal ( vp ) shunts were performed in 2 patients and cystoperitoneal shunt in 2 patients with large interhemispheric cysts causing mass effects . corpus callosal agenesis with colpocephaly was the most common associated malformation in our study [ table 2 ] . 6/10 archnoid cysts were hemispheric , 4/10 were inter hemispheric and 2/10 were located in posterior fossa . associated brain malformations seven patients had evidence of hydrocephalus , of which five cases were due to the obstruction by large arachnoid cysts and two cases were due to aqueduct stenosis . subdural collection was noted in 6 patients . in 4 patients it was subdural csf collection due to hyperfunctioning of shunts and in 2 patients it was blood due to rupture of bridging cortical veins . of these 6 patients , ventriculoperitoneal ( vp ) shunts were performed in 2 patients and cystoperitoneal shunt in 2 patients with large interhemispheric cysts causing mass effects . encephaloceles occur due to the failure of surface ectoderm to separate from the neuroectoderm , resulting in a bony defect in the cranial and/or facial bones , which allows herniation of meninges or brain tissue . encephaloceles occur in one of every 4000 live births and have no sex predilection . according to location , these are occipital ( 75% of cases ) , sincipital ( 15% ) , or basal ( 10% ) . sincipital encephaloceles involve the mid - face and occur about the dorsum of the nose , orbits , and forehead . these sincipital encephaloceles are more common in south and southeast asian populations whereas the occipital encephaloceles are more common in the western population . the sincipital encephaloceles are further subdivided into nasofrontal , nasoethmoidal , and naso - orbital types . the nomenclature used for encephaloceles is based on the origin of their roof and floor ; thus , for example , the roof and floor of frontonasal encephaloceles are the frontal and nasal bones , respectively . nasofrontal encephaloceles result from herniation through both the foramen cecum and the fonticulus frontalis and projecting along the nasal bridge between the nasofrontal sutures into the glabella ( nasofrontal region ) . nasoethmoidal encephaloceles occur when there is persistent herniation through the foramen cecum into the prenasal space and nasal cavity under the nasal bones and above the nasal septum ( nasoethmoidal region ) . moreover , naso - orbital types occur along the medial orbit at the level of the frontal process of the maxilla and the ethmoid - lacrimal bone junction ( naso - orbital region ) . affected children may present with nasal obstruction , mass in the frontal region , proptosis , or cerebrospinal fluid ( csf ) leaks from ruptured encephalocele sac with recurrent meningitis . the prognosis for the sincipital encephalocele patients is generally good and is usually associated with normal intelligence and motor development . surgery is the best treatment option for encephaloceles , and mri is the choice of imaging modality for defining the contents of an encephalocele prior to surgery . high - resolution ct may also be used to display the bone anatomy , but the intracranial extension is best defined with mri . the extent of cerebral tissue in an encephalocele is also better defined with mri , which aids in prognosis and surgical planning . the aim of the radiologist is to precisely define the type of the encephalocele ; delineate the size , contents , extension ; and identify associated anomalies . there are often significant associated intracranial anomalies , including intracranial cysts , complete / partial corpus callosal agenesis , interhemispheric lipomas , facial clefts , and migration anomalies . earlier studies postulated theories such as adhesive theory , which suggest failure of mesodermal migration into midline leading to herniation of the brain matter and resulting failure of closure of anterior neuropore . as corpus callosum forms near the site of final closure of anterior neuropore , many of these patients have associated corpus callosal agenesis which was also observed in our series . rapport et al . , postulated that this condition may have several etiological factors because mesodermal abnormalities alone can not account for the observed abnormalities . lemire et al . , thought that anterior encephaloceles result from abnormal dedifferentiation , whereas some other studies suggest neuroectodermal abnormality . from the array of associated malformations that we have observed in our series the most common associated malformation with sincipital encephaloceles is the agenesis or hypogenesis of the corpus callosum . corpus callosum is the largest cerebral commissure connecting neocortical areas and develops between 12 and 20 weeks of gestation . development occurs from front to back with the exception of the rostrum which develops after the splenium . imaging by ct and mr in complete callosal agenesis reveals widely separated and nonconverging lateral ventricles , disproportionately enlarged occipital horns ( colpocephaly ) , and an elevated third ventricle which is continuous superiorly with the interhemispheric fissure [ figure 1 ] . in sagittal mr studies , corpus callosum , cingulate gyrus , and sulcus are not seen . gyri on the medial hemispheric surface radiate outward from the high - riding third ventricle . in partial agenesis of corpus callosum , the splenium and rostrum are absent . 3-year - old male child with a swelling at nasal bridge , ( a ) axial computed tomography scan shows a nasofrontal encephalocele ( * ) , ( b and c ) axial computed tomography sections show corpus callosal agenesis as evidenced by parallel running lateral ventricles with colpocephaly ( arrow  in c ) . they are congenital lesions that occur as a result of the splitting of the arachnoid membrane . the cysts are extra - axial fluid - filled sacs , which are sharply marginated somewhat scalloped appearing lesions that parallel the csf intensity on all sequences of mri . some suprasellar cysts become very large [ figures 2 and 3 ] and cause obstructive hydrocephalus . the arachnoid cysts , particularly the interhemispheric cysts , are usually associated with corpus callosal agenesis . 2-year - old male child with a forehead swelling , ( a ) axial computed tomography bone window shows nasoethmoidal and naso - orbital type of encephalocele ( * ) . ( b ) axial , ( c ) coronal and ( d ) sagittal computed tomography sections show associated large hemispheric arachnoid cyst ( arrow ) . ( b ) axial ct section also reveals the parallel orientation left lateral ventricle ( upward arrow  ) suggestive of corpus callosal agenesis . 2-year - old female child with swelling at nasal bridge , ( a ) sagittal t1-weighted image shows a large interhemispheric arachnoid cyst ( # ) . ( b ) axial t1-weighted image in another patient with nasoethmoidal encephalocele ( * ) shows an arachnoid cyst in right temporal fossa ( arrow ) . in our series , subdural collection of the six patients four had subdural csf collection and it was thought to be due to hyperfunctioning of the shunts [ figure 4 ] , ( two had been operated with ventriculo - peritonial shunt for obstructive hydrocephalus and in the other two , ventricular catheter of the shunt was placed in the large interhemispheric cysts i.e. cysto - peritoneal shunt which caused mass effects ) . other two patients had small subdural hematomas probably due to rupture of bridging cortical veins around the herniation . 2-year - old female child with forehead swelling , ( a ) axial computed tomography section shows left subdural collection ( arrow ) in a patient with ventriculoperitoneal shunt . ( b ) axial computed tomography section in another patient with a large arachnoid cyst showing bilateral frontal subdural collection ( arrow ) with calcification of the arachnoid membrane . agyria - pachygyria complex is a defect in migration of cerebral neurons , resulting in failure of cortical gyri to develop [ figure 5 ] . the extent , distribution , and detailed structure of agyria - pachygyria vary widely , and the clinical features are accordingly very diverse . rather than one entity , pachygyric cortical abnormalities form a broad spectrum that raises different clinical and genetic problems . this complex can be of generalized / bilateral or localized / unilateral gyral malformations . generalized seizures with increased incidence of spastic quadriparesis and microcephaly are associated with the generalized / bilateral type , whereas partial seizures are more common in localized / unilateral gyral malformations and hemiparesis is the most frequent neurologic deficit . patients with bilateral or generalized gyral anomalies have poor prognosis for outcome of epilepsy and neurologic disability . the recognition of these lesions with high - resolution techniques of mri is important for planning proper treatment and genetic counseling . 4-year - old child presented with swelling over the nose and seizure , ( a ) axial computed tomography scan shows nasofrontal type of encephalocele ( * ) with mild orbital extension . ( b ) axial computed tomography section also shows agyria and pachygyria complex involving left parietooccipital lobe ( arrow  ) with corpus callosal agenesis . ( c ) higher axial computed tomography section also shows ventriculoperitoneal shunt ( # ) in interhemispheric fissure with left subdural collection ( arrow ) . we could not perform mri in many cases , which is the investigation of choice due to cost constraints . we could not perform mri in many cases , which is the investigation of choice due to cost constraints . encephaloceles are often associated with significant intracranial anomalies , with agenesis of corpus callosum being the most common . hence , a precise analysis of each case is necessary to recognize the associated malformations and establish the prognosis and risk of recurrence .