Spontaneous chronic spinal subdural hematoma associated with spinal arachnoiditis and syringomyelia

Spontaneous chronic spinal subdural hematoma is rare. We describe a case of spontaneous chronic spinal subdural hematoma associated with arachnoiditis and syringomyelia in a 76-year old woman who presented with a 14-year history of progressive myelopathy. MRI scan revealed a thoraco-lumbar subdural cystic lesion and a thoracic syrinx. The patient underwent thoracic laminectomy and decompression of the lesion, which was a subdural hematoma. A myelotomy was performed to drain the syrinx. Pathological examination revealed features consistent with chronic subdural membrane. This report attempts to elucidate the pathogenesis of chronic spinal subdural hematoma. We discuss possible etiological factors in light of the current literature and pathogenesis of both spinal subdural hematoma and syrinx formation.