Intracranial neurenteric cysts (also sometimes spelled neuroenteric) are developmental CNS lesions arising from endoderm.
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Pathology
They result from incomplete resorption of the neurenteric canal, a temporary connection between the yolk sac and amnion during early embryogenesis. Intracranial neurenteric cysts are extra-axial and in 80% of cases are in the posterior fossa anterior to the pontomedullary junction and 20% in the supratentorium adjacent to the frontal lobes. Intracranial neurenteric cysts are much less common than spinal neurenteric cysts.
Radiographic features
CT
Iso- to slightly hyper-attenuating compared to CSF with no enhancement.
MRI
MRI is the modality of choice, and appearances depend on the variable protein content 1-3:
- T1: variable signal intensity; iso- to hyperintense to CSF
- T2: variable signal intensity; hyper- to hypointense to CSF
- FLAIR: does not suppress
- DWI/ADC: facilitated diffusion
Differential diagnosis
Imaging differential considerations include:
-
epidermoid cyst
- similar to CSF in signal
- high DWI signal, ADC similar to brain parenchyma
-
arachnoid cyst
- CSF signal on all sequences
-
cystic schwannoma
- solid enhancing component
-
intracranial lipoma
- fat signal on all sequences
- suppression on fat-suppressed sequences
-
ecchordosis physaliphora
- a stalk-like connection to the clivus
- variable enhancement
-
chordoma
- usually enhances following IV contrast