RESUMEN
A neoplasm of the peripheral nerves can be obscured, especially during the early phase. The authors report a patient with sciatic nerve leiomyosarcoma. The patient's presentation and initial management are unique. A 51-year-old man with clinical manifestations of von Recklinghausen's disease reported numbness and weakness of the left leg for one and a half years. The symptoms gradually progressed. The symptoms were consistent with peripheral neuritis. The patient developed foot drop one month before coming to our service. Two episodes of biopsy confirmed leiomyosarcoma. A long, large sciatic nerve leiomyosarcoma was found intra-operatively, positioned from the upper thigh to the point where the tibial nerve passes beneath the upper margin of the soleus muscle. Surgical resection was done and confirmed the diagnosis. Decreased sensation was still intact after resection.