Pelvic Metastatic Tumor with Foot Drop due to Lumbosacral Nerve Trunk and Plexus Disorder : A Case Report

Abstract

A 76-year-old man who had undergone total bladder cancer resection one and a half year ago without recurrence or metastasis was presented. He started experiencing right lower limb pain two months prior accompanied by a right foot drop two weeks ago. On admission, severe right lower limb pain, weakness of the right anterior tibialis muscle, and toe dorsiflexion were noted. Routinely performed lumbar magnetic resonance imaging(MRI)revealed slight lumbar spinal stenosis at the L3/4 and L4/5 levels, which could not explain the exact mechanism of the patient's complaints and neurological deficits. Considering the severe leg pain and rapidly progressing foot drop, we suspected malignant lesions despite the former doctor's comments. Positron emission tomography scan was performed to rule out malignant disorders, which revealed a pelvic metastatic tumor in the right lumbosacral nerve trunk and plexus. The passage of the L5 and S1 nerves through the mass lesion at the lumbosacral plexus was clearly described by the MR neurography.In this report, the authors gained vast knowledge about medical history taking, and meticulously performed neurological and image examination depending on the targeted lesion. The authors discussed lumbosacral plexus lesion as a cause of foot drop.