Weekly Image Challenge – February 26, 2023

What do you think is the most likely diagnosis on these scans of a 32-year-old patient?

  1. Acoustic Schwannoma
  2. Arachnoid cyst
  3. Meningioma
  4. Epidermoid cyst
  5. Hemangioblastoma


Congratulations! It is an Epidermoid cyst. The contents are like CSF on T2, but there is subtle hyper-intensity on T1 as compared to the CSF in the 4th ventricle. It has diffusion restriction (bright on DWI + dark on ADC). It is heterogenous on FLAIR (not following CSF signals).

An arachnoid cyst has similar signals as CSF.

A cystic acoustic schwannoma shows contrast enhancement in its wall and often has a solid component as well.

A meningioma usually has homogenous contrast enhancement and a dural tail.

Hemangioblastoma is commonly cystic but there is a contrast-enhancing mural nodule. They are usually intra-axial.