Primary intradural extramedullary hydatid cyst.

Spinal hydatid cysts account for 1% of all cases of hydatid disease; primary intradural hydatid cysts are uncommon. We present a case of pathologically confirmed intradural spinal cyst hydatid in an otherwise healthy patient who showed no other evidence of systemic hydatid cyst disease. The patient presented with back pain, paraparesis, and weakness. An intradural extramedullary cystic lesion was identified with magnetic resonance imaging and was shown to be a hydatid cyst by histopathologic examination after surgical removal. To our knowledge, this is the 25th case of hydatid cyst at an intradural extramedullary location reported in the literature.