<unk>  also known as Pseudotumor cerebri is a process affecting the brain that appears to be -- but is not -- a tumor. It is often reversible.
Idiopathic intracranial hypertension
Arachnoiditis
Subarachnoid hemorrhage
Neoplastic meningitis
Viral meningitis
Cavernous sinus thrombosis
Cerebral venous sinus thrombosis
Gliomatosis cerebri