Primary intracranial synovial sarcoma: A case report and review of literature.

Background: Primary intracranial synovial sarcomas (PrISS) are unusual dural based mesenchymal tumors seen most commonly in the supratentorial compartment. They can mimic a spontaneous intracranial hemorrhage or a high-grade glioma on imaging.

Case Description: A 31-year-old male presented with headache and right hemiparesis for 2 weeks. CT brain revealed a left frontal spontaneous intracerebral hemorrhage. PrISS revealed a heterogeneously ring enhancing solid cystic lesion with attachment to convexity dura. Intraoperatively, it mimicked a high-grade glioma. Histopathology report showed features of a synovial sarcoma, which was later confirmed with IHC. Classical SYT-SSX2 translocation was confirmed only on RTPCR after fluorescent in situ hybridization (FISH) was negative for same. Whole body positron emission tomography (PET-CT) did not show any extracranial tumor. Despite radiotherapy, there were recurrence and tumor progression at 6 months and the patient succumbed 11 months later.

Conclusion: PrISS is an unusual aggressive intracranial neoplasm that carries a worse prognosis when compared nonintracranial synovial sarcomas. Molecular cytogenetics (FISH and RTPCR) are essential for confirming the diagnosis, though FISH seems to have a lower sensitivity and can yield false negative results as was noted in this case.