Thoracic Radiculopathy Resulting From Retrograde Neuronal Degeneration.

We report a case of thoracic radiculopathy caused by retrograde degeneration from an intercostal nerve mass. A 74-year-old woman presented with thoracic radicular pain in the T4 dermatome. Needle electromyography revealed abnormal spontaneous activity in the left paraspinal muscle. Magnetic resonance imaging of the thoracic spine showed no signs of a herniated thoracic disk or root compression but revealed a mass along the intercostal space. The pathologic findings included perineural infiltration. A mass located along the intercostal space approximately 1.8 cm from the dorsal root ganglion may cause thoracic radiculopathy via retrograde degeneration.