Unusual imaging appearance of a rare cortical ependymoma mimicking angiocentric glioma

Clinical characteristics and detection of MYB-QKI fusions in patients with angiocentric glioma

PURPOSE

Angiocentric glioma (AG), a benign tumor identified within the last two decades, was officially included in the 2007 WHO Classification of Tumors of the Central Nervous System, WHO grade I. The tumor is relatively rare, with only approximately 100 cases reported. We aim to complement the characteristics and long-term prognosis of AG, as well as to detect MYB-QKI fusions.

METHODS

The characteristics of all cases collected between 1 March 2009 and 1 March 2023 at the Beijing Sanbo Brain Hospital, Capital Medical University, were summarized and analyzed. Additionally, all fourteen patients were tested for MYB-QKI fusions.

RESULTS

AG more predominantly occurs in adolescents (median age 16.5-year-old), and commonly presents with drug-resistant epilepsy. AG is frequently localized in the supratentorial regions and only one patient is in the brainstem. Brain parenchyma atrophy, and stalk-like signs can observe in imaging. Pathologically, tumor cells are perivascular pseudorosettes, presenting immunoreactivity for GFAP, S-100, Vimentin, "dot-like" staining for EMA, and low proliferative activity. Focal cortex dysplasia was observed in four patients. Twelve of fourteen (85.7%) patients were found with MYB-QKI fusions. Completely surgical resection typically has a satisfactory prognosis with long-term follow-up.

CONCLUSION

AG is a rare benign tumor with a favorable prognosis after complete resection, characterized by refractory epilepsy, frequently occurring in adolescents. MYB-QKI fusions were detected in most AG patients, as a good defining genetic alteration pathologically. The potential presence of focal cortical dysplasia (FCD) may affect the prognosis of epilepsy.

Supratentorial cortical ependymoma: A systematic literature review and case illustration

Cortical ependymomas are currently not considered a subgroup of supratentorial ependymomas; however, there is a growing body of literature investigating the natural history of these lesions compared to supratentorial ependymomas. We performed a systematic literature review of cortical ependymomas with a focus on the natural history, clinical characteristics, and clinical outcomes of these lesions as compared to supratentorial ependymomas. Our search revealed 153 unique cases of cortical ependymomas. The mean age on presentation was 21.2 years. Males and females comprised 58.8% (90/153) and 41.2% (63/153) of cases, respectively. The most common presenting symptom was seizure activity occurring in 44.4% of the cohort (68/153). The recently recognized C11orf95-RELA fusion was identified in 13.7% of the cohort (21/153) and 95.5% of cases (21/22) reporting molecular characterization. World Health Organization grades 2 and 3 were reported in 52.3% (79/151) and 47.7% (72/151) of cases, respectively. The frontal lobe was involved in the majority of cases (54.9%, 84/153). Gross total resection was achieved in 80.4% of cases (123/153). Tumor recurrence was identified in 27.7% of cases (39/141). Mean clinical follow-up was 41.3 months. Mean overall survival of patients who expired was 27.4 months whereas mean progression-free survival was 15.0 months. Comparatively, cortical ependymomas with C11orf95-RELA fusions and supratentorial ependymomas with C11orf95 RELA fusions exhibited differing clinical outcomes. Further studies with larger sample sizes are necessary to investigate the significance of RELA fusions on survival in cortical ependymomas and to determine whether cortical ependymomas with C11orf95-RELA fusions should be classified as a distinct entity.