Sciatic nerve moneuropathy: an unusual late effect of radiotherapy

In this study we report a progressive sciatic mononeuropathy occurring 13 years after radiotherapy (56-Gy prescribed dose) for a synovial sarcoma of the thigh. Conformal dosimetric reconstitution showed that irradiation was heterogeneous and that the sciatic nerve received 66 Gy over a 25-cm length. Magnetic resonance imaging (MRI) showed muscle fibrosis and increased sciatic nerve diameter. Our observation suggests that the risk of late mononeuropathy should be considered when large-volume and high-dose radiotherapy includes a nerve trunk.