Supratentorial Cortical Ependymomas: A Retrospective Series of 13 Cases at a Single Center

Highlights

• CEs are a rare subset of supratentorial ependymomas that selectively involve the cerebral cortex.

• Most CEs are low grade and present with seizures.

• Anaplastic CEs show a greater recurrence rate and a relatively poor prognosis.

• Gross total resection with or without adjuvant radiotherapy is currently the optimal treatment for CEs.

• CEs seem to have a more favorable prognosis than other STEs.

Objective

Cortical ependymomas (CEs), supratentorial ependymomas that selectively involve the cerebral cortex, are relatively rare neoplasms that have not been extensively described. The purpose of our study was to identify the clinical features, radiologic characteristics, and treatment of a series of such tumors.

Methods

Thirteen patients with CEs from our hospital were included in this study. Epidemiologic characteristics, clinical features, imaging findings, treatment methods, and clinical outcomes were reviewed retrospectively.

Results

The patients consisted of 7 men and 6 women with mean age of 31.1 ± 23.2 years (range, 4–74 years). The most common clinical manifestation was seizure (n = 11; 85%), followed by headache (n = 2; 15%). None of the tumors were incidentally detected. Eight CEs were located in the right hemisphere and 5 in the left side. The 2 most common tumor locations were the frontal (n = 5; 38%) and parietal lobe (n = 5; 38%). All patients underwent surgical resection. Gross total resection was achieved in 12 patients (92%), and subtotal resection was performed in 1 patient (8%). Ten of the 11 patients who presented with seizure are seizure-free after surgery (91% seizure-free rate). According to the World Health Organization classification system, 9 tumors (69%) were Grade II (ependymoma) and 4 (31%) were Grade III (anaplastic ependymoma). The mean follow-up was 52 months (range, 20–88 months). No recurrence was observed in patients with Grade II CEs. Of 4 patients with Grade III CEs, 2 (50%) suffered from tumor recurrence after initial treatment.

Conclusions

CEs are a rare subset of supratentorial ependymomas that selectively involve the cerebral cortex. Most CEs are low grade and present with seizures. Anaplastic CEs show a greater recurrence rate and a relatively poor prognosis. Gross total resection with or without adjuvant radiotherapy is currently the optimal treatment for CEs. CEs seem to have a more favorable prognosis than other supratentorial ependymomas.

Introduction

Intracranial ependymomas are relatively uncommon, representing only 2%–9% of all neuroepithelial tumors.1, 2 As described in the 2016 revision of the World Health Organization (WHO) classification of central nervous system tumors, ependymal tumors can be divided into Grade I (subependymoma and myxopapillary ependymoma), Grade II (ependymoma), and Grade III (anaplastic ependymoma).³ Supratentorial ependymomas (STEs) are reported to account for 30%–50% of all intracranial ependymal tumors.4, 5 Although often considered an intraventricular tumor, approximately 50% of STEs are extraventricular and demonstrate no relationship with the ventricular system.6, 7 Cortical ependymomas (CEs), a small subset of supratentorial extraventricular ependymomas that selectively involve the cerebral cortex, are rare.5, 8 Most clinical research has been based on case reports and retrospective studies on small samples. To the best of our knowledge, fewer than 50 cases have been reported.5, 8, 9, 10, 11, 12, 13, 14, 15, 16 We reviewed our institutional case series to confirm the clinical features, treatment, and clinical outcomes of CEs. This study is the largest series reported to date on CEs from a single center and may deepen the clinical understanding of this rare tumor.