We present morphological findings observed from the study of a myxopapillary ependymoma located in the III ventricle. This tumor, which is a rare occurrence at this level, was observed in a 73-year-old woman with no relevant medical history who presented with obstructive hydrocephalus due to compression and blockage of the foramen of Monro. The good delineation of the lesion allowed its surgical excision, and histological examination of the material obtained after excisional biopsy revealed a glial neoplasm with a low degree of cytological malignancy that was strongly positive for glial fibrillary acidic protein (GFAP) as well as a myxopapillary architecture analogous to that observed in ependymomas of the filum terminale. Subsequent radiological examination allowed us to rule out a metastatic nature of the tumor, confirming its primary origin. We briefly discuss the case and review the main characteristics of this neoplasia, which is quite rare at the site identified in our patient.