Clinical question
30-year-old man with 3 year history of pain involving the right lower extremity, at times, radiating into the bottom of the foot.
- Pain clearly aggravated by driving
- Patient had good range of motion of lumbar spine with no weakness
- Negative straight leg raise
- EMG showed a normal study without any denervation
- Patient referred to MR Neurography
- Patient's outside MR lumbar spine imaging showed slight asymmetry of the S1 root with the nerve appearing slightly enlarged
- No clear enhancement
Clinical images
Interpretation
- Fusiform enlargement of the right L5 nerve and mild asymmetric hyperintensity of the right S1 nerve. Diffuse fascicular enlargement suggesting diffuse neuronal involvement
- Minimal enhancement
- DTI - Low FA values (0.2-0.3) and high ADC values - 1.4 - 2.0. Tractography shows mildly disrupted tracts
- Diagnosis - Benign peripheral nerve sheath tumor, likely segmental schwannoma
Consequences for treatment
- It was inadvisable to operate on the lesion, since only limited improvement was expected
- Final diagnosis - Benign peripheral nerve sheath tumor
- The diagnosis was proven for a benign peripheral nerve sheath tumor as it did not change over two year follow-up