Thoracic intradural arachnoid cyst associated with surgical removal of epidural hematoma--case report.

A 54-year-old woman presented with a very rare association of spinal intradural arachnoid cyst and spinal epidural hematoma manifesting as paraparesis subsequent to severe back pain. Magnetic resonance (MR) imaging disclosed a ventral epidural hematoma extending from the T-4 to T-6 levels and compressing the spinal cord ventrally. Emergent surgical evacuation of the epidural hematoma was carried out 22 hours after the onset. MR imaging obtained 2 days after surgery showed enlargement of the dorsal subarachnoid space at the T-3 to T-8 levels. The patient could walk independently within 6 months after discharge, but paraparesis recurred 3 years after surgery. MR imaging showed formation of an intradural arachnoid cyst, which compressed the spinal cord dorsally. She underwent arachnoid cystectomy, and recovered ambulation postoperatively. This case of intradural arachnoid cyst of the thoracic spine which appeared after surgical removal of an epidural hematoma at the same spinal level indicates some association between the epidural hematoma and the arachnoid cyst.