Spinal intradural hydatid cyst causing arachnoiditis: A rare etiology of cauda equina syndrome

This study aims to focus on a rare presentation of spinal hydatid cyst as cauda equine syndrome and misdiagnosed as intradural extramedullary (IDEM) benign lesion on magnetic resonance imaging. In this article, we report a case of spinal hydatid cyst masquerading as IDEM tumor, and intraoperatively, we accidently find clumped granuloma with severe arachnoiditis and hydatid cyst in lumber region, which was present as bilateral S1 radiculopathy with cauda equina syndrome. An 11 year old boy who presented with symptoms and signs of cauda equina syndrome and planned for surgical excision. His radiological impression was IDEM possibly neurofibroma. To our surprise, we found multiple intradural cystic lesions with arachnoiditis. Dissecting in plane cyst was flushed out, and surgical cavity was irrigated with 3% saline. Postoperatively histopathology and serum tests confirmed the diagnosis of hydatid cyst. Hydatid disease is rare cause of cauda equine syndrome which can be miss diagnosed on radiological investigations. A high index of suspicion should be kept especially in a young patient from the Indian subcontinent.