Non-neoplastic tumor associated cysts

Radiopaedia • CC-by-nc-sa 3.0 • de

Non-neoplastic tumor associated cysts (TACs) are benign fluid-containing cysts adjacent to, but not within, a neoplasm.

Pathology

Non-neoplastic tumor associated cysts are most likely represent trapped encysted pools of CSF adjacent to large extra-axial neoplasms. When a tumor grows it traps the CSF between it and the adjacent brain. It is considered a tumor "epiphenomenon".

Radiographic features

Extra-axial non-neoplastic tumor associated cysts are more common than intra-axial, e.g. meningioma, craniopharyngioma, vestibular schwannoma

  • smooth well-demarcated cyst
  • can be single or multiple
  • it abuts the tumor directly
  • vary from small to very large size
  • enhancement: absent or minimal

Differential diagnosis