Original Chiari 3 description: Upper cervical spinal dysraphism with protruding encephalocele containing herniated hindbrain
Associated intracranial findings of Chiari malformation, including "lemon" calvarium, callosal hypogenesis, tectal beaking
Frontoethmoidal/sincipital/anterior: 15% (↑ in Southeast Asia)
Nasoethmoidal: Most common form; defect between nasal bone & nasal cartilage (through foramen cecum)
Nasofrontal/frontonasal: Defect between frontal & nasal bones (through fonticulus frontalis)
Nasoorbital: Least common form; defect at junction of maxilla (anterior) & lacrimal bone with lamina papyracea of ethmoid bone (posterior)
Parietal: 10% (↑ in Japan at 38%)
Atretic parietal cephaloceles most common
Midline posterior parietal scalp mass over small bony defect; elevation of falx/tentorial junction; persistent falcine venous sinus; fibrous tract splits superior sagittal sinus
Majority have benign clinical course
Parietal meningoencephaloceles uncommon
Usually associated with significant brain anomalies → poor prognosis
Basal/nasopharyngeal: Up to 10% of cases
Transethmoidal: Defect in ethmoids only with mass in anterior nasal cavity
Transsphenoidal/sphenopharyngeal: Defect in sphenoid bone only, usually extends into nasopharynx but can also be confined to sphenoid sinuses
Sphenoethmoidal: Through sphenoid and ethmoid bones with mass in posterior nasal cavity
Sphenoorbital: Defect through superior orbital fissure with unilateral exophthalmos; rare though cases associated with neurofibromatosis type 1 reported
Sphenomaxillary: Very rare, 1-2 case reports
Remaining calvarium: Rare
Interfrontal
Interparietal
Anterior fontanelle
Posterior fontanelle
Temporal (lateral)
Mastoid &/or petrous temporal bone: Rare
Cavum trigeminale: Rare
IMAGING
General Features
CT Findings
MR Findings
Ultrasonographic Findings
Imaging Recommendations
DIFFERENTIAL DIAGNOSIS
PATHOLOGY
General Features
Gross Pathologic & Surgical Features
CLINICAL ISSUES
Presentation
Demographics
Natural History & Prognosis
Treatment
DIAGNOSTIC CHECKLIST
Consider
Reporting Tips
Selected References
Boppel T et al: Excavating Meckel's cave: cavum-trigeminale-cephaloceles (CTCs). J Neuroradiol. 42(3):156-61, 2015
Morone PJ et al: Temporal lobe encephaloceles: a potentially curable cause of seizures. Otol Neurotol. 36(8):1439-42, 2015
Copp AJ et al: Neural tube defects: recent advances, unsolved questions, and controversies. Lancet Neurol. 12(8):799-810, 2013
Tirumandas M et al: Nasal encephaloceles: a review of etiology, pathophysiology, clinical presentations, diagnosis, treatment, and complications. Childs Nerv Syst. 29(5):739-44, 2013
Barkovich et al:a Pediatric Neuroimaging: 5th edition. Lippincott Williams & Wilkins: Philadelphia. 501-21, 2012
Bui CJ et al: Institutional experience with cranial vault encephaloceles. J Neurosurg. 107(1 Suppl):22-5, 2007
Original Chiari 3 description: Upper cervical spinal dysraphism with protruding encephalocele containing herniated hindbrain
Associated intracranial findings of Chiari malformation, including "lemon" calvarium, callosal hypogenesis, tectal beaking
Frontoethmoidal/sincipital/anterior: 15% (↑ in Southeast Asia)
Nasoethmoidal: Most common form; defect between nasal bone & nasal cartilage (through foramen cecum)
Nasofrontal/frontonasal: Defect between frontal & nasal bones (through fonticulus frontalis)
Nasoorbital: Least common form; defect at junction of maxilla (anterior) & lacrimal bone with lamina papyracea of ethmoid bone (posterior)
Parietal: 10% (↑ in Japan at 38%)
Atretic parietal cephaloceles most common
Midline posterior parietal scalp mass over small bony defect; elevation of falx/tentorial junction; persistent falcine venous sinus; fibrous tract splits superior sagittal sinus
Majority have benign clinical course
Parietal meningoencephaloceles uncommon
Usually associated with significant brain anomalies → poor prognosis
Basal/nasopharyngeal: Up to 10% of cases
Transethmoidal: Defect in ethmoids only with mass in anterior nasal cavity
Transsphenoidal/sphenopharyngeal: Defect in sphenoid bone only, usually extends into nasopharynx but can also be confined to sphenoid sinuses
Sphenoethmoidal: Through sphenoid and ethmoid bones with mass in posterior nasal cavity
Sphenoorbital: Defect through superior orbital fissure with unilateral exophthalmos; rare though cases associated with neurofibromatosis type 1 reported
Sphenomaxillary: Very rare, 1-2 case reports
Remaining calvarium: Rare
Interfrontal
Interparietal
Anterior fontanelle
Posterior fontanelle
Temporal (lateral)
Mastoid &/or petrous temporal bone: Rare
Cavum trigeminale: Rare
IMAGING
General Features
CT Findings
MR Findings
Ultrasonographic Findings
Imaging Recommendations
DIFFERENTIAL DIAGNOSIS
PATHOLOGY
General Features
Gross Pathologic & Surgical Features
CLINICAL ISSUES
Presentation
Demographics
Natural History & Prognosis
Treatment
DIAGNOSTIC CHECKLIST
Consider
Reporting Tips
Selected References
Boppel T et al: Excavating Meckel's cave: cavum-trigeminale-cephaloceles (CTCs). J Neuroradiol. 42(3):156-61, 2015
Morone PJ et al: Temporal lobe encephaloceles: a potentially curable cause of seizures. Otol Neurotol. 36(8):1439-42, 2015
Copp AJ et al: Neural tube defects: recent advances, unsolved questions, and controversies. Lancet Neurol. 12(8):799-810, 2013
Tirumandas M et al: Nasal encephaloceles: a review of etiology, pathophysiology, clinical presentations, diagnosis, treatment, and complications. Childs Nerv Syst. 29(5):739-44, 2013
Barkovich et al:a Pediatric Neuroimaging: 5th edition. Lippincott Williams & Wilkins: Philadelphia. 501-21, 2012
Bui CJ et al: Institutional experience with cranial vault encephaloceles. J Neurosurg. 107(1 Suppl):22-5, 2007