Bone lesion with fluid-fluid level

A spontaneous cerebrospinal fluid leak (sCSF leak) is a cerebrospinal fluid leak – a leak of cerebrospinal fluid that surrounds the brain and spinal cord from the protective dural sac for no apparent reason. The dura mater is the tough, outermost of layer of the meninges, the membranes surrounding the brain and spinal cord. [Source: Wikipedia ]