Subependymoma of the Cervicothoracic Spinal Cord

Subependymomas are rare, World Health Organization (WHO) grade I tumors [1,2]. They typically arise in the ventricles and represent less than 1% of intracranial tumors [3]. Spinal subependymomas are even less frequent, comprising approximately 2% of all symptomatic spinal cord tumors [4]. They are usually intramedullary and located in the cervical region, however thoracic and lumbar lesions have also been reported [2,5,6]. Radiologically, intracranial subependymomas present as well defined intraventricular lesions that are classically T2-weighted images (WI) hyper intense and T1WI hypo or isointense to white matter in MRI [5,7]. Heterogeneity on T2WI is often reported and is related to cystic changes, blood products or calcifications, particularly in larger lesions [5]. Calcifications and blood products can manifest as low signal intensity on T2WI gradient echo sequence. Subependymomas typically do not enhance or only mildly enhance. Avid enhancement has been reported particularly in lesions located in the fourth ventricle. The tumor size typically ranges from 1 to 2 cm, however lesions greater than 5 cm have also been reported [2,5]. Spinal subependymomas usually present as eccentric, well-defined lesions with mild to moderate enhancement. Lesions of the spine have significant associated edema [2,6].