The authors have reviewed the literature and recorded the distinguishing features of intraspinal enterogenous cysts. There are no characteristic clinical findings or history associated with this disease. These congenital space-occupying lesions frequently go undiagnosed, and the patient may be treated for many years as a case of multiple sclerosis. The teratogenic "determination period" is decisive for the development of anomalies affecting one, two, or all three of the germinal layers. All of these cysts belong to the same group, and their structure is an expression of the differing determination periods. The various theories about their etiology are discussed. True intraspinal enterogenous cysts are usually found in the cervical region. After careful operative removal, the prognosis is favorable.