title: Secondary adult encephalocele with abscess formation of calcified frontal sinus mucocele.
abstract: BACKGROUND
  Although encephalocele is a rare congenital abnormality, secondary encephalocele is extremely rare and can cause fatal complications. Here, we report a case of secondary encephalocele caused by frontal sinus wall defect due to chronic sinusitis, which was completely removed by cranialization with autologous bone graft. A 50-year-old man with a 10-year history of chronic sinusitis visited our hospital due to suddenly altered mentality characterized by stupor. Computerized tomography scanning and magnetic resonance imaging revealed an enlarged left frontal sinus with sinusitis. The frontal sinus cavity was calcified, and the left frontal lobe had herniated into the cavity accompanied by yellow pus. A large dural defect was also found around the frontal sinus area. After removal of the abscess and some of the frontal lobe, frontal skull base repair by cranialization was performed using autologous bone graft. Streptococcus pneumoniae was cultured from the cerebrospinal fluid (CSF), necessitating treatment with antibiotics. After the operation, the mental status of the patient improved and no CSF leakage was observed.
  
  
  CONCLUSIONS
  In addition to correct diagnosis and early treatment including antibiotics, the surgical repair of defects is needed in patients with secondary encephalocele to prevent further episodes of meningitis. Surgical correction of frontal sinus encephalocele can be achieved through bifrontal craniotomy or endoscopic transnasal repair. If a patient has CSF leakage, open craniotomy may facilitate repair of the dural defect and allow for cranialization of the sinus.
  
  
  CONCLUSIONS
  Removal of dysplastic herniated brain tissue and cranialization of the frontal sinus may be a good option for treating secondary encephalocele and its associated complications, including meningitis, abscess formation, and infarction of the herniated brain parenchyma.
authors.affiliation: Department of Neurosurgery, Chungbuk National University Hospital, College of Medicine, Chungbuk National University, 776, 1 Sunhwanro, Gaesindong, Sewongu, Cheongju, South Korea, 28644.
authors.forename: Byeong Ho
authors.initials: BH
authors.lastname: Oh
authors.affiliation: Department of Pathology, Chungbuk National University Hospital, College of Medicine, Chungbuk National University, Cheongju, South Korea.
authors.forename: Ok-Jun
authors.initials: OJ
authors.lastname: Lee
authors.affiliation: Department of Neurosurgery, Chungbuk National University Hospital, College of Medicine, Chungbuk National University, 776, 1 Sunhwanro, Gaesindong, Sewongu, Cheongju, South Korea, 28644. youngseokparkmd@gmail.com.
authors.forename: Young Seok
authors.initials: YS
authors.lastname: Park
mesh_terms: D001922:Brain Abscess / Q000150:complications / Q000000981:diagnostic imaging / Q000209:etiology*; D002114:Calcinosis / Q000150:complications* / Q000000981:diagnostic imaging; D004677:Encephalocele / Q000150:complications / Q000000981:diagnostic imaging / Q000209:etiology*; D005626:Frontal Sinus / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009078:Mucocele / Q000150:complications* / Q000000981:diagnostic imaging / Q000601:surgery; D015898:Tomography Scanners, X-Ray Computed
keywords: Chronic sinusitis; Encephalocele; Frontal sinus; Meningitis; Skull base