Long-Term Seizure Outcomes and Predictors in Patients with Dysembryoplastic Neuroepithelial Tumors Associated with Epilepsy

Abstract

To determine the predictors and the long-term outcomes of patients with seizures following surgery for dysembryoplastic neuroepithelial tumors (DNTs); Methods: Clinical data were collected from medical records of consecutive patients of the Department of Neurosurgery of Sanbo Brain Hospital of Capital Medical University with a pathological diagnosis of DNT and who underwent surgery from January 2008 to July 2021. All patients were followed up after surgery for at least one year. We estimated the cumulative rate of seizure recurrence-free and generated survival curves. A log-rank (Mantel-Cox) test and a Cox proportional hazard model were performed for univariate and multivariate analysis to analyze influential predictors; Results: 63 patients (33 males and 30 females) were included in this study. At the final follow-up, 49 patients (77.8%) were seizure-free. The cumulative rate of seizure recurrence-free was 82.5% (95% confidence interval (CI) 71.8-91.3%), 79.0% (95% CI 67.8-88.6%) and 76.5% (95% CI 64.8-87.0%) at 2, 5, and 10 years, respectively. The mean time for seizure recurrence-free was 6.892 ± 0.501 years (95% CI 5.91-7.87). Gross total removal of the tumor and a short epilepsy duration were significant predictors of seizure freedom. Younger age of seizure onset, bilateral interictal epileptiform discharges, and MRI type 3 tumors were risk factors for poor prognosis; Conclusions: A favorable long-term seizure outcome was observed for patients with DNT after surgical resection. Predictor analysis could effectively guide the clinical work and evaluate the prognosis of patients with DNT associated with epilepsy.

Keywords: dysembryoplastic neuroepithelial tumors; epilepsy; prognosis; seizure outcome; surgery.

Figure 1

Flowchart describing the procedures and exclusion and inclusion criteria of this study. DNTs, dysembryoplastic neuroepithelial tumors.

Figure 2

The MRI features and histopathological features of DNTs. The MRI features of type 1 (A–D): axial and sagittal slices, single cystic-like hypointensity on T1WI (A,B) and hyperintensity on T2WI (C), ring hyperintensity around the isointensity tumor with a clear gray-white matter boundary on FLAIR image (D); the MRI features of type 2 (E–H): axial and coronal slices, hypointensity on T1WI (E), hyperintensity on T2WI (F,G) and FLAIR image (H), all with a nodular-like iso-hypointensity; the MRI features of type 3 (dysplastic-like): axial and sagittal slices (I–L), slightly blurring of the gray-white matter demarcation with hypointense signal on axial T1WI (I), hyperintense signal on T2WI (J) and FLAIR images (K,L). Histopathological features of DNT (M,N): specific glioneuronal elements with a typical columnar structure composed of small oligodendrocytes and neurons floating within an interstitial fluid (H&E, ×200); (N): tumor cells were “striped” in loose areas of tumor tissue (H&E, ×200).

Figure 3

(A): Number of patients by seizure outcomes according to follow-up duration since surgery; (B): year-to-year analysis of seizure outcomes, the seizure-free rate remained basically stable.

Figure 4

Kaplan–Meier curves for seizure outcomes. The X-axis represents time in years, and the Y-axis represents the proportion. (A): The rate fluctuated in the first few years after surgery and gradually stabilized in subsequent years. (B): Analysis by age at onset; (C): analysis by duration; (D): analysis by IEDs; (E): analysis by MRI subtype; (F): analysis by surgical types. Addition: because of the limited sizes of MRI type 2 and NTR, MRI type 1 and 2 were classified as Non-Type 3, STR and NTR were classified as Non-GTR in this Kaplan–Meier curve.