Primary ovarian ependymoma is a rare neuroectodermal neoplasm that can arise from immature ovarian teratoma. Due to the paucity of this entity, a complete molecular analysis of these tumors has not been done, thus creating a challenge for finding an effective and safe therapeutic treatment. In limited literature, patient with primary ovarian ependymoma showed various responses to an array of individualized therapies ranging from surgeries and chemotherapies. Here, we present a 38-year-old female with persistent ovarian ependymoma with molecular profile similar to traditional central nervous system ependymoma that is irresponsive to multiple cytoreduction and clinical experimental therapies. Therefore, a prompt recognition and reporting of this entity can greatly aid in expanding the understanding and standardization of therapies for this neoplasm.

Pediatric brain tumors are the most common solid tumors in children, causing the highest number of cancer-related deaths at young ages. Although existing therapies have improved the 5-year overall survival rate of PBT patients, some high-risk brain tumors continue to resist current treatments. Additionally, the survivors endure devastating long-term side effects, including cognitive defects and sensory and endocrinal dysfunctions. In the past two decades, immunotherapies have evolved significantly, with great success in many cancers. Immunotherapies developed specifically for PBTs also show promising results. Currently, scores of clinical trials are underway to evaluate the safety and feasibility of a wide-range of immunotherapeutics for PBTs, and this review overviews the most recent advances, including the exciting progress made toward treating medulloblastoma, pediatric glioma, and ependymoma. We summarized the cutting-edge immunotherapies under development, including immune checkpoint blockade, chimeric antigen receptor (CAR)-T cell therapy, natural killer (NK)-cell therapy, cancer vaccines, and oncolytic virus therapy. We find that the results from the recently concluded or ongoing clinical trials on safety and feasibility are very encouraging; however, non-responsiveness and tumor recurrence still haunt them. While this review judges the scope of the current immunotherapies, it also lays out strategies to find alternate solutions for persisting issues.

Ependymoma is responsible for 8–10% of all pediatric brain tumors and constitutes the third most common brain tumor in children. No robust molecular markers are yet in routine clinical use. Surgical resection and adjuvant radiotherapy cure approximately 40-70% of pediatric patients with ependymoma. In our centre, we have been using prophylactic valproic acid treatment for brain tumor patients. Initial observations indicated that valproate could have a beneficial effect in the survival of patients. Recent observations by other authors have shown that patients with glioblastoma benefited from the treatment with valproic acid, a histone deacetylase inhibitor. We have used random survival forest, a novel ensemble survival modelling method to study a single- center, small number cohort of pediatric patients with ependymoma. This analysis has confirmed surgery resection extent and treatment with radiotherapy as independent predictors of overall survival. Treatment with valproic acid was also a predictor of higher survival in this cohort. These results highlight the potential usefullness of the random survival forest model in gathering information from retrospective data. More data is needed about the possible influence of histone deacetylase inhibition by valproic acid in the survival of patients with ependymoma.