Cysts associated with intramedullary ependymomas of the spinal cord: clinical, MRI and oncological features.

Purpose: Few published articles have explicitly focused on cysts associated with intramedullary (IM) ependymomas. The objective was to assess the clinical, MRI, and oncological results of patients operated for an IM ependymoma associated with a cystic portion.

Methods: During the study period, 23 IM tumors resected were cystic ependymomas. The modified McCormick scale was used to assess the neurological function of patients. The diagnosis of cystic spinal cord tumor was made on preoperative MRI.

Results: Two types of cysts were identified according to their location: either intra-tumoral cysts (ITC) or satellite cysts (SC). ITC (52.2%) were more frequent than SC (21.7%), but 26.1% of patients presented both. ITC were enhanced by gadolinium while SC were not. The solid portion of ependymomas with ITC was significantly larger than the one of ependymomas with SC (p = 0.002). The mean time to the first occurrence of symptoms was significantly shorter in patients with neurological deficit than those without a deficit (p = 0.04). GTR was achieved in 78.2% of cases. Complete excision of the cysts was easier when they were larger (p = 0.006). Sixty percent of cysts disappear postoperatively. Persistence of satellite cysts despite GTR of the tumor, and with no recurrence of a tumor on the post-operative MRI, was observed for 3 patients.

Conclusion: ITC and SC are different in location, volume, gadolinium enhancement. Their surgical management is different since ITC are resected while SC are drained. Cystic recurrence and/or persistence are not synonymous with tumor recurrence.