The term enterogenous cyst is reserved for growths arising exclusively from the foregut, i.e., from the entodermal layer. An extensive review of the literature by Caruso et al. Our case was not associated with dysraphic lesions. The benign lesions contain mainly mature elements, such as mature cartilage, squamous epithelium, skin appendages, mucosa, and neural elements. In immature teratomas, the immature components are almost exclusively of neuroepithelial origin, only rarely originating from primitive mesenchymal or renal tissue.
Recurrences develop mainly in the case of immature teratomas.
The immature teratoma grading system of Norris et al. Grade I is applied to a tumor that contains abundant mature tissue intermixed with loose mesenchymal tissue, with occasional mitoses, immature cartilage and tooth analogue. Since so few cases are seen, a classification system for intramedullary spinal teratomas has not been developed. Therefore, the classification system used for ovarian teratomas has been applied to that of intramedullary spinal teratoma. The present case was classed as grade II because it contained immature neuroepithelial components which were found in no more than three foci per low-power field, though it also had some mature tissues.