Intracranial epidermoid cyst


  • A 49 years old lady
  • Presented with recent onset of fitting episodes
  • No neurological deficit
MRI of brain in axial planes
MRI brain in sagittal T2WI
MRI brain in coronal planes, T1 post contrast
MRI brain in coronal plane FLAIR sequences

MRI findings:

  • An extra axial mass at left temporal lobe measuring 4x3x4 cm (red arrows)
  • It shows intermediate signal on T1, hyperintense on T2
  • Not suppressed on FLAIR (yellow arrows).
  • No enhancement post contrast.
  • Restricted diffusion on DWI/ADC sequences
  • No extension into the cavernous sinus
  • No enhancing nodule or abnormal leptomeningeal enhancement

Diagnosis: Epidermoid cyst (HPE proven)


  • Intracranial epidermoid cyst is also known as ectodermal inclusion cyst or congenital inclusion cyst.
  • It represent 0.2-1.8 % of all primary intracranial tumours
  • It is the most common congenital intracranial tumours
  • Symptoms depends on the site of tumour
  • Location: CP angle (40-50%), 4th ventricle (17%), middle cranial fossa (10-15%)
  • CT scan shows round or lobulated mass, >95% hypodense resembling CSF, 10-25% contain calcifications, no enhancement post contrast. It may cause bone erosion.
  • MRI shows slightly hyperintense to CSF on T1WI, isointense (65%) to slightly hyperintense (35%) to CSF on T2WI, does not fully suppressed on FLAIR and restricted diffusion on DWI. No contrast enhancement post contrast. MRS shows no NAA, choline or lipid, resonance from lactate.


Author: radhianahassan