We present a very rare case of an extradural nerve root cavernoma of the lumbar spine. The patient had signs of radiculopathy for the last 3 years. Conservative treatment was unsuccessful. The MRI-image revealed a lesion mimicking neurinoma of the left L3 nerve root. Surgical removal of the lesion was performed by an extreme lateral transmuscular approach. Intraoperatively, the lesion showed signs of intratumoural bleeding. In the histological analysis, a cavernoma of the nerve root was established. Despite the benign nature of these very rare lesions, complete surgical removal should be performed since a spontaneous regression is not to be expected and surgery relieves the patients from their symptoms.