RARE-45. SARCOMAS INVOLVING THE CENTRAL NERVOUS SYSTEM AT INITIAL PRESENTATION IN CHILDREN AND YOUNG ADULTS: A CASE SERIES

Sarcomas of bone, soft tissue, or neural origin may occasionally invade the central nervous system (CNS), causing diagnostic and therapeutic challenges. We aim to investigate the clinical features of sarcomas involving the CNS at initial presentation. During 2015/01–2019/12, nine consecutive patients (4 Males and 5 Females) younger than 30 years of age treated at a University Healthcare System in Northern Taiwan were included. The median age was 8.7 years (range, 2–24 years); diagnoses were Ewing Sarcoma with EWSR1 rearrangements (n=4), CIC-NUTM1 Sarcoma (n=1), Osteosarcoma (n=2), Malignant Peripheral Nerve Sheath Tumor (MPNST; n=1), and extramedullary myeloid sarcoma (n=1). The tumors originated from the skull (n=1), dura (n=1), vertebra (n=4), spinal canal (n=1), or extra-CNS sites (n=2). Four patients had metastases (1 Ewing sarcoma, 2 osteosarcoma, and 1 extramedullary myeloid sarcoma). The main symptom at diagnosis was facial/eye pain (n=2), back pain (n=3), arm weakness (n=1), or gait disturbance (n=3). Upfront neurosurgical decompression (n=7) or urgent radiotherapy (n=1) was performed in most patients. At a median follow-up duration of 20.1 months, the overall survival rate was 70%. All patients with Ewing sarcoma (n=4) and CIC-NUTM1 sarcoma (n=1) achieved Complete Response after surgery, interval-compressed chemotherapy, radiotherapy, and adjuvant chemotherapy. Patients with stage IV osteosarcoma (n=2) had Partial Response; the patients with MPNST and extraskeletal myeloid sarcoma died of Progressive Disease at 18 and 3 months after diagnosis, respectively. We conclude that timely decompression, early diagnosis, and histology-driven multimodality treatment are effective strategies in managing sarcomas involving the CNS.