====== Intracranial cyst differential diagnosis ======

Differential diagnosis of a cystic brain lesion must contemplate primary [[neoplasm]], [[metastases]] (lung and breast neoplasms are the most common cause), brain [[abscess]], [[tuberculoma]] and [[neurocysticercosis]].
(NCC).

see [[Cystic tumor]].
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A [[craniopharyngioma]] (CP) is an embryonic [[malformation]] of the [[sellar region]] and [[parasellar region]]. 

Its relation to [[Rathke's cleft cyst]] (RCC) is controversial, and both lesions have been hypothesized to lie on a continuum of [[ectoderm]]al [[cystic lesion]]s of the [[sellar region]]. 
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[[Porencephaly]]

1. [[Intracranial arachnoid cyst]]s: Typically lined with meningothelial cells

2. [[suprasellar cyst]] from dilated [[third ventricle]]

3. [[interhemispheric cyst]] from [[porencephaly]]

4. [[neuroectodermal cyst]]s (glioependymal cysts): intraparenchymal, located near ventricles

5. old [[infarct]]: if it communicates with a ventricle it is called a [[porencephalic cyst]]

6. tumor cysts (the solid portion may sometimes be isodense to brain on CT):

a) [[ganglioglioma]]: usually solid but may appear cystic on CT

b) [[pilocytic astrocytoma]]: usually has enhancing mural nodule

c) neurilemmomas may be cystic

d) supratentorial ependymomas are often cystic 

7. infectious

a) abscess

b) cysticercosis: see [[Neurocysticercosis]]

c) hydatid cyst: see Echinococcosis 

8. [[pineal cyst]]s 

9. [[colloid cyst]] 

10. [[Rathke’s cleft cyst]] 

11. [[giant aneurysm]]

12. on CT, a low density non-enhancing tumor can mimic a cyst

13. chronic subdural hematoma or hygroma may mimic a cyst

14. [[Posterior fossa cyst]]: 
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[[Choroid plexus cyst of the third ventricle]].

[[Colloid cyst]].

[[Cystic lesion]]