Spinal arachnoiditis mimicking a spinal cord tumor: a case report and review of the literature.

We report on an unusual case of idiopathic arachnoiditis mimicking a spinal cord tumor in a 50-year-old man with progressive paraparesis. The medical imaging work-up showed an enlarged terminal cone with adjacent cysts. Although there was no enhancement of the terminal cone or the surrounding structures, the diagnosis of spinal cord tumor was maintained and surgery was carried out. Exploration of the cauda equina and the tissue surrounding the terminal cone did not reveal a tumor. The patient improved dramatically after surgery but the symptoms recurred 1 year later. We review arachnoiditis, its pathology, and its treatment with special attention drawn to the primary form of spinal arachnoiditis.