RESUMEN
Objective: to make a bibliographical review in purpose of an infrequent case of cystic dilatation of the conus ventriculus terminalis. Description: Female patient of 34 years old, who consults for invalidating anal pain and rectal tenesmus. The MRI shows an image compatible with cystic dilatation of ventriculus terminalis. Intervention: The treatment consists in simple wide laminectomy; midline microsurgical myelotomy and marsupialization with subaracnoidal space. Following myelotomy and fenestration a significant reduction in size of the cyst was seen in MRI. Conclusion: The patient clinical response was good in relation with her initial situation (invalidating anal pain), only persists the parestesis in the right dermatomas L5-S1. This last symptom requires medical co-adyuvance (CBZ). Radiological evolution of the lesion was excellent. To 5 years only post-surgical changes are evident.