Neoplastic lumbosacral plexopathy is one of the most disabling complications in subjects with cancer. Its clinical presentation is characterized by pain, muscle weakness and sensory complaints in one or both limbs.There are only a few cases in the neurosurgical literature as it is mostly treated by pain therapy, radiotherapy and/or chemotherapy. However, surgical exploration may be necessary in some patients without a definitive diagnosis, or those who do not respond to medical therapy, even with narcotics. A 50-year-old female with lumbosacral plexopathy 3 years after treatment of cervical carcinoma is reported. Her severe leg pain did not resolve even by narcotics, and there were weaknesses of knee flexion and foot dorsi- and plantar flexions. Her radiological examinations revealed a mass looking like an abscess at the entrance of the true pelvis, and her infection markers were high. Surgical exploration was performed because of suspicion of intrapelvic abscess. However, a metastatic lymph node compressing the plexus was found. Her pain clearly diminished after operation, and she did not require narcotics but the weakness was unchanged. She was treated by chemotherapy after the surgery and her pain was mild after three months.