Intracranial synovial sarcoma: A clinical, radiological and pathological study of 16 cases

Synovial sarcoma (SS) is a tumor of unknown origin and is extremely rare in the central nervous system. Most studies on intracranial SS included only one or two cases. To better understand the disease, we review a series of primary intracranial SS. 16 primary intracranial SS in Tiantan Hospital during 2008–2017 were included. The clinical characteristics, including radiological and histological examination, operative records, and prognoses were reviewed. The case series included nine male and seven female patients with an average age of 23.8 years. Radiological results showed that the supratentorial region (81.25%) was the most common site of the brain involved. All patients were misdiagnosed as non-SS tumors. Gross total resection (GTR) was achieved in 12 cases (75.0%), and subtotal resection (STR) was achieved in 4 cases. All cases showed the characteristic SYT-SSX fusion gene, as detected by RT-PCR. The mean progression-free survival time (PFS) was 10.0 months and the mean overall survival time (OS) was 15.5 months. Multivariate analysis revealed that GTR and postoperative adjuvant radiotherapy were independent factors for PFS (HR = 6.143, 95% CI = 1.491–25.312; P = 0.012, HR = 6.143, 95% CI = 1.491–25.312; P = 0.012 respectively) and OS (HR = 9.000, 95% CI = 1.627–49.773; P = 0.012, HR = 0.017, 95% CI = 0.001–0.213; P = 0.002 respectively). Intracranial SS were more frequently observed in the supratentorial region and in young patients without sex predilection. We recommend adjuvant radiation regardless of the extent of resection. More patients and longer follow-up periods were needed to further elucidate the biological features of intracranial SS.