Cystic structures that can rupture into the CSF:
(1) craniopharyngioma (with cystic component)
(2) cholesteatoma
(3) epidermoid cyst
(4) intracranial dermoid cyst
Cysts lined by a squamous epithelium may contain oils that contribute to the irritation.
Clinical features:
(1) headache
(2) low-grade fever
(3) meningism
(4) depressed level of consciousness
Hydrocephalus may develop in chronic cases as fibrosis develops.
Laboratory findings on CSF examination:
(1) leukocytosis (neutrophilic if acute, lymphocytic if chronic)
(2) negative Gram stain
(3) sterile CSF culture (negative bacterial, fungal and viral cultures)
(4) possibly cellular debris and/or oily material
Following resection of an intracranial cyst it is recommended that followup scans be performed in order to detect cyst recurrence.
