Vertebral Hydatidosis- Physical examination revealed impaired sensation in both legs and weak foot flexion. Laboratory tests showed an elevated total white-cell count (18,800 per cubic millimeter; reference range, 4000 to 10,000) with a normal absolute eosinophil count and a C-reactive protein level of 49 mg per liter (reference value, <5). Magnetic resonance imaging of the spine revealed a lobulated lesion of the 9th thoracic vertebra with an epidural component (Panel A, arrow; a close-up image is shown in Panel B)...Pathological testing revealed cystic echinococcosis (hydatidosis), and reverse-transcriptase–polymerase-chain-reaction assay identified Echinococcus granulosus. Echinococcus is a parasitic cestode that can infect dogs and other pets and farm animals, with humans as incidental hosts. Infection can cause cystic lesions in the liver and lungs and also in the central nervous system and bones. #clinical #radiology #MRI #NEJM #vertebral #hydatidosis #cystic #echinococcosis #echinococcus #granulosus