encephalocele is a rare condition that consists of herniation of cerebral matter through openings of dura and skull
the incidence of the congenital form is estimated to be 1 per 3,000 to 10,000 live births.1 
 2 many classification systems for encephalocele exist ; however , the most widely accepted is that from matson and ingraham,3 based on the location of the encephalocele : basal , sincipital , convexity , and atretic .
convexity encephalocele , subdivided into frontal , parietal , occipital , and cervico - occipital , is the most common type.3 those lesions are usually located at midline , extending from the nasal region to the occiput , although off midline temporal regions have also been reported.4 
 5 a majority of the encephaloceles are congenital and manifest in childhood . here ,
we report a rare case of a traumatic intradiploic encephalocele ( ie ) presenting with contralateral hemiparesis several decades after an initial pediatric trauma .
a 45-year - old caucasian , right - handed man presented to our emergency department ( ed ) with 3 to 4 weeks history of progressive gait disturbances and left lower extremity weakness .
his pertinent medical history was negative for any recent history of head trauma , but was significant for a moderate traumatic brain injury ( tbi ) at the age of 9 years , where he fell off a tree and sustained a closed parietal skull fracture with no posttraumatic cognitive or neurologic deficits .
he had no history of seizures , central nervous system infections , stroke , or brain tumor .
his neurological exam at admission was significant for left hemiparesis ( strikingly more pronounced on lower than upper extremity ) and positive left pronator drift testing .
he was initially seen in the ed where a magnetic resonance imaging ( mri ) showed ie of the right parasagittal parietal bone containing portions of the right precentral gyrus and surrounding brain parenchyma ( fig .
a 3-mm ( a , b ) coronal and ( c ) axial reformats in both ( a ) brain and ( b ) bone windows on ( d ) ct and coronal mri showing herniated brain parenchyma .
ct , computed tomography ; mri , magnetic resonance imaging . noncontrasted computed tomography ( ct ) demonstrated a well - circumscribed , 4.3  3.7 cm area of osteolysis in the right parasagittal parietal bone , with internal soft tissue attenuation ( fig .
c ) , complete erosion of the inner table , and noncontiguous lytic changes of the outer table ( fig .
1b , c ) . mri with and without gadolinium contrast administration demonstrated a right parasagittal dural defect with intradiploic herniation of the right precentral gyrus ( fig
. 1d ) . there was no restricted diffusion to suggest acute infarction ( fig .
( a ) axial 5 mm se ) t2 images , ( b ) axial 5 mm blood suppressed se t1 images , ( c ) axial 5 mm flair images , and ( d ) axial 5 mm postcontrast se t1 images ( 12 mm gadavist ) .
ct , computed tomography ; mri , magnetic resonance imaging ; se , spin echo after initial neurosurgical evaluation in the ed , the patient was admitted to the neurosurgical ward and started on dexamethasone 4 mg intravenously every 6 hours .
his left lower extremity weakness responded positively to the initial steroids therapy , with partial but transient improvement on his leg weakness to antigravity strength and ambulatory with a rolling walker .
he was reluctant to proceed with surgical intervention initially , and elected to continue hospital observation for a few days .
since no sustainable improvement on his strength was seen after 2 days of high - dose dexamethasone treatment , he decided to proceed with surgical intervention . under general anesthesia , and using ct - guided intraoperative frameless stereotactic navigation , the area correspondent to the encephalocele was identified and marked .
the calvarium was exposed through a bicoronal incision . the bone overlying the encephalocele appeared to be mottled and thin .
cortical brain matter was visualized directly underneath the most thinned portions of the right parietal bone .
it appeared pale with no evidence of cortical vasculature , and the usual gyral anatomy had been lost .
starting from the areas of bone dehiscence , the craniectomy was then extended centrifugally until identification of the normal inner table surrounding the whole encephalocele .
once the margins of the encephalocele were completely identified and dissected , a large craniotomy incorporating the bone defect was completed using high - speed craniotome ( fig .
the pial - arachnoid plane surrounding that area was very sclerotic and firmly adherent to the encephalocele pedicle . due to the risk of vascular injury to an already friable but apparently still eloquent brain , we decided not to proceed with arachnoidal opening or resection of the encephalocele sac .
the bone flap was replaced with a titanium mesh used for coverage over the craniectomy site . 

( a ) intraoperative picture showing large craniotomy incorporating the bone defect . the pial - arachnoid plane surrounding that area was very sclerotic and firmly adherent to the encephalocele pedicle .
the defect was shown in ( b ) and ( c ) for dorsal and ventral side , respectively .
he tolerated the procedure well and was kept in intensive care unit for 24 hours without complications .
postoperative noncontrasted ct head revealed no ischemic changes on the surrounding parenchyma and adequate reduction of the encephalocele ( fig .
( c ) a 3-mm axial bone window and coronal reformats in both ( b ) brain and ( a ) bone windows on postoperative ct .
on 2-month follow - up , his preoperative left leg weakness has greatly improved with near resolution of preoperative hemiparesis .
a 45-year - old caucasian , right - handed man presented to our emergency department ( ed ) with 3 to 4 weeks history of progressive gait disturbances and left lower extremity weakness .
his pertinent medical history was negative for any recent history of head trauma , but was significant for a moderate traumatic brain injury ( tbi ) at the age of 9 years , where he fell off a tree and sustained a closed parietal skull fracture with no posttraumatic cognitive or neurologic deficits .
he had no history of seizures , central nervous system infections , stroke , or brain tumor .
his neurological exam at admission was significant for left hemiparesis ( strikingly more pronounced on lower than upper extremity ) and positive left pronator drift testing .
he was initially seen in the ed where a magnetic resonance imaging ( mri ) showed ie of the right parasagittal parietal bone containing portions of the right precentral gyrus and surrounding brain parenchyma ( fig .
a 3-mm ( a , b ) coronal and ( c ) axial reformats in both ( a ) brain and ( b ) bone windows on ( d ) ct and coronal mri showing herniated brain parenchyma .
noncontrasted computed tomography ( ct ) demonstrated a well - circumscribed , 4.3  3.7 cm area of osteolysis in the right parasagittal parietal bone , with internal soft tissue attenuation ( fig .
c ) , complete erosion of the inner table , and noncontiguous lytic changes of the outer table ( fig .
mri with and without gadolinium contrast administration demonstrated a right parasagittal dural defect with intradiploic herniation of the right precentral gyrus ( fig .
( a ) axial 5 mm se ) t2 images , ( b ) axial 5 mm blood suppressed se t1 images , ( c ) axial 5 mm flair images , and ( d ) axial 5 mm postcontrast se t1 images ( 12 mm gadavist ) .
ct , computed tomography ; mri , magnetic resonance imaging ; se , spin echo after initial neurosurgical evaluation in the ed , the patient was admitted to the neurosurgical ward and started on dexamethasone 4 mg intravenously every 6 hours .
his left lower extremity weakness responded positively to the initial steroids therapy , with partial but transient improvement on his leg weakness to antigravity strength and ambulatory with a rolling walker .
he was reluctant to proceed with surgical intervention initially , and elected to continue hospital observation for a few days .
since no sustainable improvement on his strength was seen after 2 days of high - dose dexamethasone treatment , he decided to proceed with surgical intervention .
after initial neurosurgical evaluation in the ed , the patient was admitted to the neurosurgical ward and started on dexamethasone 4 mg intravenously every 6 hours .
his left lower extremity weakness responded positively to the initial steroids therapy , with partial but transient improvement on his leg weakness to antigravity strength and ambulatory with a rolling walker .
he was reluctant to proceed with surgical intervention initially , and elected to continue hospital observation for a few days .
since no sustainable improvement on his strength was seen after 2 days of high - dose dexamethasone treatment , he decided to proceed with surgical intervention .
under general anesthesia , and using ct - guided intraoperative frameless stereotactic navigation , the area correspondent to the encephalocele was identified and marked .
cortical brain matter was visualized directly underneath the most thinned portions of the right parietal bone .
it appeared pale with no evidence of cortical vasculature , and the usual gyral anatomy had been lost .
starting from the areas of bone dehiscence , the craniectomy was then extended centrifugally until identification of the normal inner table surrounding the whole encephalocele .
once the margins of the encephalocele were completely identified and dissected , a large craniotomy incorporating the bone defect was completed using high - speed craniotome ( fig .
the pial - arachnoid plane surrounding that area was very sclerotic and firmly adherent to the encephalocele pedicle . due to the risk of vascular injury to an already friable but apparently still eloquent brain , we decided not to proceed with arachnoidal opening or resection of the encephalocele sac .
the bone flap was replaced with a titanium mesh used for coverage over the craniectomy site . 

( a ) intraoperative picture showing large craniotomy incorporating the bone defect . the pial - arachnoid plane surrounding that area was very sclerotic and firmly adherent to the encephalocele pedicle .
the defect was shown in ( b ) and ( c ) for dorsal and ventral side , respectively .
he tolerated the procedure well and was kept in intensive care unit for 24 hours without complications .
postoperative noncontrasted ct head revealed no ischemic changes on the surrounding parenchyma and adequate reduction of the encephalocele ( fig .
( c ) a 3-mm axial bone window and coronal reformats in both ( b ) brain and ( a ) bone windows on postoperative ct .
on 2-month follow - up , his preoperative left leg weakness has greatly improved with near resolution of preoperative hemiparesis .
a cephalocele is a protrusion of cerebral contents through a defect in the dura or skull .
these lesions are classified according to their location and contents ( meninges , brain parenchyma , ventricles , and/or vasculature ) .
the presence of brain parenchyma characterizes an encephalocele , whereas those without brain parenchyma are called meningocele .
the location of these lesions varies as they may involve the posterior fossa , occipital , basal , frontoethmoidal , and/or parietal regions.6 
 7 
 8 depending on the etiology , cephaloceles are further classified as primary or secondary . in the case of primary cephaloceles
, a congenital defect exists in the dura or skull , usually at the site of a cranial suture , representing a midline closure defect of the neural tube . in secondary cephaloceles ,
a preceding injury such as infection , tumor , trauma , or surgery is usually the underlying cause . in this case report
, we present an extremely rare phenomenon of a symptomatic posttraumatic parietal ie manifesting 36 years following traumatic head injury .
medline and pubmed database literature search revealed only 11 cases previously reported in the literature . 

five had no history of trauma , four cases9 
 10 
 11 ( including the present study ) were found to be posttraumatic and/or iatrogenic , and one did not comment on any supposed etiology for the encephalocele.12 therefore , traumatic injuries to the skull were the reported etiology of the cephalocele in approximately 40% of the literature cases .
the initial insult typically occurs in childhood with a delayed diagnosis decades later after manifestation of signs and symptoms , if at all.13 
 14 
 15 
 16 
  abbreviation : nr , not reported ; lle , left lower extremity ; lue , left upper extremity ; rle , right lower extremity ; rue , right upper extremity .
patil and etemadrezaie9 reported a 64-year - old man had head trauma 8 months prior to experiencing an enlarging palpable scalp mass .
lenthall and penney10 reported a 15-month - old infant sustained a head injury and presented with growing fracture with pulsatile mass 9 months later .
our patent presented with progressive hemiparesis 36 years following pediatric traumatic head injury . depending on where the lesion is , symptoms may vary widely , from seizures to aphasia , numbness , hemiparesis , or even asymptomatic . of the case
reports , the most common symptoms are hemiparesis / weakness11 
 12 
 17 ( four patients including the present study ) , seizures5 
 17 ( two patients ) , palpable mass9 
 10 ( two patients ) ; one was incidentally found.18 
  surgical repair with or without excision of the herniated brain parenchyma is generally performed in symptomatic patients .
clinical response is generally favorable with minor improvement in symptoms to completely asymptomatic on follow - up . in order for an encephalocele to occur
d'almeida and king19 postulated that if only the inner table and dura mater are affected by the fracture from tbi , the diploic space is opened and enlarged over time by pulsation of cerebrospinal fluid ( csf ) .
lenthall and penney10 stressed the importance of an outward driving force for enlargement of the diploic space secondary to normal brain growth , csf pulsatility , or increased intracranial pressure , as also seen in the coughing spell reported by loumiotis et al.12 patil and etemadrezaie9 proposed that low - velocity blunt injury may fracture only the inner table , which is thinner .
the depression tears the dura and the recoil creates a negative pressure that forces the underlying arachnoid and brain into the diploic space .
menk et al13 proposed that there could be congenital factors , although the article focused on intradiploic pseudomeningocele as opposed to ie .
they proposed that intradiploic cyst develops through foveolae granulare which are anatomical and physiological defects that form a hollow space of the inner table .
these granulations usually lie in the frontoparietal bone and near the superior sagittal sinus . in the setting of head trauma , dura and arachnoid membranes
differential diagnosis includes epidermoid or dermoid cyst , cavernous hemangioma , eosinophilic granuloma , plasmacytoma , metastasis , and osteosarcoma.18 mri is necessary to establish a diagnosis .
herniation of brain parenchyma through a dural defect into intradiploic space is what separates this lesion from the rest on the differential , as is seen in our case .
however , definitive diagnosis still lies in surgical exploration and histopathological examination.13 
 20 
 21 
  surgical correction with craniotomy , reduction of herniated cortex , excision of herniated parenchyma , and cranioplasty have been reported as the optimal management strategy .
if a patient remains asymptomatic , observation and regular follow - up may be adequate .
surgical excision of the herniated brain parenchyma depends on the proximity to the location of the vital functional areas of the brain such as the motor cortex . in our case , because of the risk of vascular injury to an already friable but apparently still eloquent brain , we decided not to proceed with arachnoidal opening or resection of the encephalocele sac .
functional mri , magnetic source imaging of evoked sensory potential , or intraoperative cortical mapping have been used to help with defining eloquent cortex.17 frameless neuronavigational systems as used in our case are recommended to enhance precision .
regardless of the method , meticulous dissection must be exercised to maximize recovery and minimize complications .
this case is unique in that the patient became symptomatic several decades after a pediatric head trauma .
 encephalocele is a rare condition that consists of herniation of cerebral matter through openings of dura and skull . 
 a majority of encephaloceles are congenital and manifest in childhood . 
 we present a case of a 45-year - old man presenting with contralateral hemiparesis and found to have an extremely rare phenomenon of a symptomatic posttraumatic parietal intradiploic encephalocele ( ie ) manifesting 36 years following pediatric traumatic head injury . 
 computed tomography and magnetic resonance imaging confirmed herniation of brain tissue into the intradiploic space . 
 surgical treatment with reduction of the encephalocele achieved near resolution of preoperative hemiparesis on follow - up . 
 the pathogenesis and a literature review of ie are discussed . 
Introduction
Case Report
History and Examination
Preoperative Neuroimaging
Preoperative Hospital Course
Operative Procedure
Perioperative Course and Follow-up
Discussion