Intraspinal sparganosis is a very rare disease caused by infestation of migrating larva of Spirometra mansonoides. Only 7 cases of intraspinal sparganosis have been reported in the literature. We report a case in a 26 year-old woman presenting with left side sciatica and intermittent urinary incontinence for more than a year. Magnetic resonance imaging (MRI) revealed a large cauda equina mass with heterogeneous enhancement in the L4 to S2 spinal canal. An intradural mass matted with the nerve roots of the cauda equina was found during surgery. Pathological examination revealed chronic granulomatous inflammation with fragments of a helminth sparganum. We present this intraspinal sparganosis case with emphasis on its rarity, MRI features of this unique cauda equina inflammatory mass, and a literature review.