Primary intraventricular synovial sarcoma of the brain with recurrence-case presentation

Background: We report a case of recurrent primary intraventricular synovial sarcoma of the brain with no extracranial primary, initially reported as a haemangiopericytoma. We believe this is the first reported case of primary intraventricular synovial sarcoma at this site.Case presentation: A 27-year-old male presented to hospital with a new onset of seizures. Imaging revealed a left ventricular trigone mass with surrounding oedema. He underwent a left occipito-temporal craniotomy and resection with the histology reported as haemangiopericytoma. Resection was followed by adjuvant radiation treatment. Seven years later follow-up imaging revealed a 4 mm contrast enhancing lesion in the previous surgical bed. The patient underwent resection. Histological analysis of the recurrence revealed a spindle cell tumour with a SS18 gene rearrangement consistent with synovial sarcoma. Retrospective fluorescent in-situ hybridisation analysis of original histology also revealed a SS18 gene rearrangement consistent with a diagnosis of synovial sarcoma.Conclusion: Synovial sarcoma should be included as part of the differential diagnosis for patients presenting with intraventricular spindle cell tumours in the brain.

Automated summary

This case report presents a recurrent primary intraventricular synovial sarcoma that was initially misdiagnosed as a haemangiopericytoma. The study highlights the importance of considering synovial sarcoma as part of the differential diagnosis for intraventricular spindle cell tumors in the brain.