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Cephalocele
Usha D. Nagaraj, MD; A. Carlson Merrow, Jr., MD, FAAP
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KEY FACTS

  • Terminology

    • Imaging

      • Top Differential Diagnoses

        • Clinical Issues

          • Diagnostic Checklist

            TERMINOLOGY

            • Definitions

              • Extracranial extension of intracranial contents through defects of skull & dura; categorized by contents & location
                • Congenital more common than acquired
                  • Congenital forms typically sporadic, though chromosomal (trisomy 13, 18), syndromic (Meckel-Gruber), & disruptive (amniotic band) etiologies described
                  • Acquired forms may be due to trauma, surgery, infection
              • Contents
                • Meningocele: Meninges & CSF only
                • Encephalocele: Brain, meninges, CSF
                  • Also called meningoencephalocele
                • Meningoencephalocystocele: Ventricle, brain, meninges, CSF
                • Atretic cephalocele: Dermal, meningeal, & glial elements with fibrous tract extending intracranially
              • Locations
                • Occipital: Most common location, up to 80% of cases
                  • Supra- &/or infratentorial structures in cephalocele, including tentorium cerebelli & dural venous sinuses
                  • Occipitocervical (Chiari 3): Rare
                    • Involving occipital bone, foramen magnum, &/or upper cervical spine (spinal dysraphism)
                    • 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

                                        1. Boppel T et al: Excavating Meckel's cave: cavum-trigeminale-cephaloceles (CTCs). J Neuroradiol. 42(3):156-61, 2015
                                        2. Morone PJ et al: Temporal lobe encephaloceles: a potentially curable cause of seizures. Otol Neurotol. 36(8):1439-42, 2015
                                        3. Copp AJ et al: Neural tube defects: recent advances, unsolved questions, and controversies. Lancet Neurol. 12(8):799-810, 2013
                                        4. 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
                                        5. Barkovich et al:a Pediatric Neuroimaging: 5th edition. Lippincott Williams & Wilkins: Philadelphia. 501-21, 2012
                                        6. Bui CJ et al: Institutional experience with cranial vault encephaloceles. J Neurosurg. 107(1 Suppl):22-5, 2007
                                        7. Hedlund G: Congenital frontonasal masses: developmental anatomy, malformations, and MR imaging. Pediatr Radiol. 36(7):647-62; quiz 726-7, 2006
                                        8. Rowland CA et al: Are encephaloceles neural tube defects? Pediatrics. 118(3):916-23, 2006
                                        9. Sdano MT et al: Temporal bone encephaloceles. Curr Opin Otolaryngol Head Neck Surg. 13(5):287-9, 2005
                                        10. Lowe LH et al: Midface anomalies in children. Radiographics. 20(4):907-22; quiz 1106-7, 1112, 2000
                                        11. Patterson RJ, et al: Atretic parietal cephaloceles revisited: an enlarging clinical and imaging spectrum? AJNR 19:791-5, 1998
                                        Related Anatomy
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                                        Related Differential Diagnoses
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                                        References
                                        Tables

                                        Tables

                                        KEY FACTS

                                        • Terminology

                                          • Imaging

                                            • Top Differential Diagnoses

                                              • Clinical Issues

                                                • Diagnostic Checklist

                                                  TERMINOLOGY

                                                  • Definitions

                                                    • Extracranial extension of intracranial contents through defects of skull & dura; categorized by contents & location
                                                      • Congenital more common than acquired
                                                        • Congenital forms typically sporadic, though chromosomal (trisomy 13, 18), syndromic (Meckel-Gruber), & disruptive (amniotic band) etiologies described
                                                        • Acquired forms may be due to trauma, surgery, infection
                                                    • Contents
                                                      • Meningocele: Meninges & CSF only
                                                      • Encephalocele: Brain, meninges, CSF
                                                        • Also called meningoencephalocele
                                                      • Meningoencephalocystocele: Ventricle, brain, meninges, CSF
                                                      • Atretic cephalocele: Dermal, meningeal, & glial elements with fibrous tract extending intracranially
                                                    • Locations
                                                      • Occipital: Most common location, up to 80% of cases
                                                        • Supra- &/or infratentorial structures in cephalocele, including tentorium cerebelli & dural venous sinuses
                                                        • Occipitocervical (Chiari 3): Rare
                                                          • Involving occipital bone, foramen magnum, &/or upper cervical spine (spinal dysraphism)
                                                          • 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

                                                                              1. Boppel T et al: Excavating Meckel's cave: cavum-trigeminale-cephaloceles (CTCs). J Neuroradiol. 42(3):156-61, 2015
                                                                              2. Morone PJ et al: Temporal lobe encephaloceles: a potentially curable cause of seizures. Otol Neurotol. 36(8):1439-42, 2015
                                                                              3. Copp AJ et al: Neural tube defects: recent advances, unsolved questions, and controversies. Lancet Neurol. 12(8):799-810, 2013
                                                                              4. 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
                                                                              5. Barkovich et al:a Pediatric Neuroimaging: 5th edition. Lippincott Williams & Wilkins: Philadelphia. 501-21, 2012
                                                                              6. Bui CJ et al: Institutional experience with cranial vault encephaloceles. J Neurosurg. 107(1 Suppl):22-5, 2007
                                                                              7. Hedlund G: Congenital frontonasal masses: developmental anatomy, malformations, and MR imaging. Pediatr Radiol. 36(7):647-62; quiz 726-7, 2006
                                                                              8. Rowland CA et al: Are encephaloceles neural tube defects? Pediatrics. 118(3):916-23, 2006
                                                                              9. Sdano MT et al: Temporal bone encephaloceles. Curr Opin Otolaryngol Head Neck Surg. 13(5):287-9, 2005
                                                                              10. Lowe LH et al: Midface anomalies in children. Radiographics. 20(4):907-22; quiz 1106-7, 1112, 2000
                                                                              11. Patterson RJ, et al: Atretic parietal cephaloceles revisited: an enlarging clinical and imaging spectrum? AJNR 19:791-5, 1998