EPEN-12. MULTIPLE RECURRENCES OF ANAPLASTIC EPENDYMOMA WITH EXTRA AXIAL AND EXTRA NEURAL METASTASIS IN A PEDIATRIC PATIENT

BACKGROUND: Ependymomas are the third most common CNS tumor in the pediatric population, accounting for 10% of all CNS tumors. Co-occurring extraneural and extracranial metastasis of ependymomas are extremely rare, with only 1 reported adult case in current literature. CASE DESCRIPTION: We describe the case of a patient with multiple reoccurrences of anaplastic ependymoma. Initial imaging showed a 5 x 8 x 8 cm complex cystic mass with nodular enhancing components within the left occipital lobe. The 4(th) ventricle was intact and imaging was negative for metastasis. Pathology following resection demonstrated perivascular pseudorosettes, areas of calcification, and increased mitotic activity. Biopsy revealed GFAP, EMA, neurofilament, INI-1, and was negative for CAM5.2, confirming anaplastic ependymoma. Methylation studies for PFA or PFB subgroup differentiation were not available. The patient had recurrences at 4-, 5-, and 6-years after his initial diagnosis. Seven years from his initial diagnosis, the patient underwent resection of four nodular lesions from the occipital lobe and surrounding soft tissue. Pathology of these lesions and the lymph nodes/soft tissue confirmed anaplastic ependymoma. A PET scan showed increase uptake in the supraclavicular lymph nodes and had multiple bilateral pulmonary nodules. Scans at 3 months post-surgery were negative for leptomeningeal metastases but showed further lymph node involvement with progression of pulmonary disease. CONCLUSION: Co-occurring extraneural and extracranial metastasis of ependymoma is a rare occurrence across all populations. To our knowledge, this would be the first published pediatric case of anaplastic ependymoma with lymph node, soft tissue, and pulmonary involvement. Treatment of ependymoma itypically local and the utility of chemotherapy remains unclear. Treatment options for extraneural mets is very limited, illustrating the need for new therapies and further studies directed at understanding the biology of these tumors and the factors that could influence their ability to metastasize to extraneural and extracranial sites.