Rare Case of a Cervical Ventral Root Filament Neuroma Mimicking a Sequestrated Disc Herniation in Association with Ossification of the Posterior Longitudinal Ligament.

Spinal neuromas related to chronic irritation or remote trauma may arise from unrecognized repetitive minor injury to the spinal cord or nerve roots, yet detailed descriptions with precise preoperative imaging findings are rare. We report a 59-year-old man with a 6-month history of severe dysesthesia and numbness in the neck and left upper limb, followed by progressive weakness over 2 months. He had undergone splenectomy after a traffic accident 23 years earlier. Computed tomography revealed ossification of the posterior longitudinal ligament, osteophytes, and a disc herniation at the left C5/C6 level. Magnetic resonance imaging demonstrated a slightly enhancing peripheral mass compressing the spinal cord. The differential diagnosis included meningioma and sequestrated cervical disc herniation. During surgery, only the swollen, non-functioning C6 ventral root filaments were resected, while functioning filaments were preserved. Histopathological examination confirmed a neuroma composed of disorganized axonal bundles consistent with chronic irritation- or remote trauma-related changes. The patient showed mild postoperative improvement. Chronic irritation appears to be the predominant contributor. Irritation-related neuromas should be considered in the differential diagnosis of intradural extramedullary lesions arising from C6 ventral root filaments, even when the trauma history is remote.