Type

Content

Location

Type A

Clear water or CSF-like fluid

A1 Extratumoural, CSF

surrounded by arachnoid

membrane

A2 Extratumoural, clear water

without the presence of

arachnoid membrane

Type B

Xanthochromic fluid

B1 Extratumoural, no wall

B2 Intratumoural, thin rim of

enhancing tumour

surrounding the cyst or

enhancing nodule

Type C

Dark brown or yellow dirty fluid

Intratumoural

Type D

Contains both clear-water

Extratumoural or peritumoural cysts and

dark brown intratumoural small cysts