Neurenteric cyst

see Intracranial neurenteric cysts.

No uniformly accepted nomenclature. Working definition: CNS cyst lined by epithelium primarily resembling that of the GI tract, or less often, the respiratory tract. Congenital. Not true neoplasms. Most common alternate term: enterogenous cyst. Less common terms include teratomatous cyst, intestinoma, archenteric cyst, enterogene cyst, and endodermal cyst. Usually affect the upper thoracic and lower cervical spine.53 Associated developmental vertebral anomalies (e.g. diastematomyelia) are common. Rarely intracranial (see below). Spinal neurenteric cysts (NEC) may have a fistulous or fibrous connection to the GI tract (through a spinal dysraphism) and some call these endodermal sinus cysts. Occurs as a result of the persistence of the neurenteric canal (temporary duct between the notochord and the primitive gut (amniotic and yolk sacs) formed during week 3 of embryogenesis by the breakdown of the floor of the notochordal canal).

Type of foregut duplication cyst, associated either with vertebral or central nervous system abnormalities. They are usually classified as spinal or intracranial.

Endodermal cysts, also known as neurogenic, neurenteric cyst, foregut, bronchogenic, respiratory, epithelial, teratomatous, or gastrocytoma cysts, can be found in the central nervous system, predominantly in the subarachnoid space of the cervical and thoracic spinal cord.

The intraspinal cysts are usually extramedullary (80%) and ventral in location. They most commonly occur in the thoracic region (42%).

Pathology

They result from incomplete resorption of neurenteric canal.

Radiographic features

CT

The cyst is seen as hypoattenuating lesion which may show soft tissue attenuation.

MRI

It is the investigation of choice and the appearance depends on the variable protein content.

T1 - variable signal intensity

T2 - variable signal intensity

These lesions can recur and hence MRI is also used for follow up.

Jiramongkolchai report, a child with an endodermal cyst of the third nerve and highlight neuroimaging findings, pathological correlation, clinical course, and patient management ¹⁾.