Intradural extramedullary primary hydatid cyst of the spine: a case report and review of literature.

Primary intradural extramedullary hydatid cyst is a rare form of parasitic infection, causing focal neurological signs, commonly observed in sheep-raising areas of the world. We report a rare case of intradural, extramedullary spinal cyst, which we had misdiagnosis in the first surgery, because of rarity of the case. A 55-year-old man presented to our hospital in August 2008. He was admitted to our clinic because of lumbar pain of increasing severity and progressive difficulty with walking and stiffness of both lower limbs, which had lasted for 1 month. On the basis of imaging results, arachnoid cyst of the lumbar spine was diagnosed. Due to rapid progression of the patient's symptoms toward spastic paraplegia, he underwent an emergency surgical decompression procedure. The patient underwent exploratory surgery using a posterior approach. A L1-L2 laminectomy was performed. After opening the dura, an intradural extramedullary cystic mass was determined. The surgical specimen measured 6 × 2 cm and was described as a whitish, pearl-like, semitranslucent, cystic material, which was thought to be parasitic. Surgery has to be followed by albendazole therapy.