Introduction: Ependymomas are slow-growing neuroectodermal tumors that may arise from various parts of the central nervous system. Anaplastic ependymoma represents 3-5% of ependymomas, and it is rarely found in adults and the infratentorial area, particularly the cerebellum. This paper discusses the first reported case of an adult female with anaplastic cerebellar ependymoma who underwent surgery and was treated with chemotherapy for tonsillar herniation.

Case Presentation: This is a case of a 58-year-old Filipino female with a five-month history of dizziness, headache, nausea, and vomiting. Cranial computed tomography (CT) scan revealed the presence of hydrocephalus with enhancing lesions at the right cerebellum. The patient underwent ventriculoperitoneal shunting (VPS) with sub-total excision and biopsy of the right cerebellum. Histology and immunochemistry were consistent with a high-grade anaplastic ependymoma (WHO Grade III). Cerebrospinal fluid and spinal magnetic resonance imaging (MRI) were negative for tumors. The initial plan was to undergo limited field external beam radiation therapy to the cerebellum. However, the patient was lost to follow-up. Two months after surgery, she presented with similar symptoms. MRI revealed tonsillar herniation and interval progression of the mass compressing the fourth ventricle, pons, and medulla oblongata; thus, medical decompression urgent chemotherapy with cisplatin and etoposide were started. After four chemotherapy sessions, repeat cranial MRI revealed resolution of tonsillar herniation and interval regression of the mass.

Conclusion: This paper presented a rare case of anaplastic cerebellar ependymoma with tonsillar herniation, successfully treated with chemotherapy. Radiotherapy is the standard of care following surgical resection. Still, our case management showed that in a patient with tumor progression presenting with tonsillar herniation, alternative management is to give systemic chemotherapy instead of radiotherapy.