Clinical and Magnetic Resonance Features of Spinal Myxopapillary Ependymoma

BACKGROUND AND OBJECTIVES: Spinal myxopapillary ependymoma (SMPE) is a common primary tumor of the cauda equina region. Despite its benign nature, SMPE is difficult to resect, and early seeding along the neural axis may necessitate further adjuvant therapy. The aim of this study was to analyze the clinical and MRI characteristics of SMPE to enhance pretreatment diagnosis and outcomes. METHODS: We retrospectively reviewed patients with SMPE at 2 institutions between 2003 and 2023. Preoperative MRI was reviewed to determine the tumor characteristics. The primary outcomes were progression-free survival and overall recurrence rates, which were analyzed using Kaplan–Meier statistics. RESULTS: A total of 20 patients with SMPE were recruited (mean age: 33.1 ± 14.8 years, 70% male). The follow-up period was 103 ± 70.2 months. “Insects in amber” sign and midline position are the most common characteristics indicative of SMPE on MRI and are observed in 90% and 85% of patients, respectively. Seven (35%) patients experienced tumor recurrence. Younger age ( P = .008), tumors >50.2 mm in size ( P = .019), conus medullaris involvement ( P = .043), the presence of tumor seeding before the operation ( P < .001), and incomplete resection ( P = .002) were associated with a higher rate of tumor recurrence after the operation. The 5- and 10-year progression-free survival rates were estimated to be 70% and 65%, respectively. CONCLUSION: SMPE can be diagnosed based on pretreatment MRI findings, such as the “insect in amber” sign and a midline tumor location. We recommend adjuvant therapy and close postoperative follow-up for patients at high risk of tumor recurrence to improve outcomes.