title: Excavating Meckel's cave: Cavum-trigeminale-cephaloceles (CTCs).
abstract: OBJECTIVE
  Cavum-trigeminale-cephaloceles (CTCs) are rare lesions of Meckel's cave and the petrous apex. Despite distinctive imaging features, they are frequently mistaken for other petrous apex lesions. In contrast to many of these entities, CTCs do--when asymptomatic--not require any invasive work-up or even surgical excision. Since correct diagnosis has profound impact on clinical decision-making, we report on a series of CTCs with distinct imaging features and their important differential diagnoses.
  
  
  METHODS
  We report a retrospective series of 5 patients with CTCs and the associated imaging features including the absence of diffusion restriction and solid contrast enhancement as well as their size, anatomical location with regard to adjacent structures and the remodeling or erosion of surrounding bony structures.
  
  
  RESULTS
  Our series contains the largest CTC that has, to the best of our knowledge, been reported so far. It revealed a deep cervical extension and was initially mistaken for a branchial cleft cyst. Furthermore, we show that CTCs can erode or remodel important structures such as canalis nervi hypoglossi, canalis Vidiani, foramen rotundum, ovale, lacerum and spinosum without causing clinical symptoms.
  
  
  CONCLUSIONS
  In contrast to previous reports in which asymptomatic CTC did not include critical structures such as the foramina rotundum, ovale, lacerum or spinosum or the hypoglossal or Vidian canal, we show that CTCs can be asymptomatic even when eroding or remodeling such clinically important structures. When extending below the skull base, CTCs are a rare differential diagnosis to cystic cervical lesions such as type II branchial cleft cysts.
authors: Department of Neuroradiology, University Hospital of Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany. Electronic address: tobias.boppel@med.uni-heidelberg.de.
authors: Tobias
authors: T
authors: Boppel
authors: Department of Neuroradiology, University Hospital of Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany.
authors: Martin
authors: M
authors: Bendszus
authors: Department of Neuroradiology, University Hospital of Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany; FMRIB Centre, Department of Clinical Neurology, University of Oxford, Oxford, UK.
authors: Andreas J
authors: AJ
authors: Bartsch
mesh_terms: D000293:Adolescent; D000368:Aged; D001935:Branchioma / Q000175:diagnosis*; D003937:Diagnosis, Differential; D004677:Encephalocele / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D010579:Petrous Bone / Q000473:pathology*; D012189:Retrospective Studies; D019291:Skull Base / Q000473:pathology*; D013100:Sphenoid Bone / Q000473:pathology*
keywords: Cavum meckeli; Cavum-trigeminale cephalocele; Empty sella; Petrous apex cephalocele