Thorn in My Spine: A case of a retained intradural extramedullary foreign body.

Foreign bodies in the spine are most commonly traumatic and managed in an acute setting. A few case reports describe foreign bodies resulting in delayed neurologic dysfunction, most commonly iatrogenic or from penetrating injury. We present a 30-year old man with lower extremity weakness from an intradural extramedullary foreign body granuloma secondary to a thorn, which was initially thought to represent an aggressive malignant process with intra and extramedullary involvement on MR. Postoperatively, the patient endorsed a causative trauma several years prior. We also present a review of the few similar published cases as well as the described prototypical imaging features and pathologic process.