[Dilation of the ventriculus terminalis, an infrequent cause of lower back pain. Magnetic resonance findings].

Introduction: Ventriculus terminalis is the name given to a congenital disorder that consists in the appearance of a small oval ependymal cystic cavity in the conus medullaris. It is formed during embryogenesis as a result of the differentiation between the canalisation and regression of the spinal cord. The aim of this study is to describe the findings obtained by magnetic resonance (MR) imaging concerning the dilation of the ventriculus terminalis in a symptomatic patient.

Case Report: A 41-year-old female with a three-year history of lower back pain and irradiated pain in the left leg, together with paresthesias. The physical exploration revealed hypoesthesia with a low level of sensitivity in D12, L1 and L2. MR images revealed the presence of a cystic lesion located in the conus medullaris, with a well defined outline, and which was not enhanced following contrast IV.

Conclusion: The ventriculus terminalis is the ependymal cavity that lies in the conus medullaris. It may present an abnormal dilation and we need to know of its existence, where it is typically located and its signal characteristics in MR in order to be able to diagnose and differentiate it from cystic tumours situated in the same place, which can display a similar appearance in MR images. The therapeutic management of these patients will depend on their clinical progress. MR scanning is fundamental for diagnosing and monitoring symptomatic patients.