“…However, in arachnoid cysts with a sudden reduction in size, it should be taken into account that bleeding findings may also occur, and sudden changes in intracranial dynamics may cause neurological deterioration by causing sudden changes in intracranial pressure. 1,4,8 It can be thought that arachnoid cysts that gradually shrink in size may have their own internal dynamics, the cyst content may be resorbed slowly through an opening in the cyst wall, or the cyst size may change in different processes with osmotic activities. Arachnoid cysts should be considered static formations that do not show a very high size change.…”