Increased phantom limb pain as an initial symptom of spinal neoplasia

Phantom limb pain is a common sequela of amputation. Studies suggest that over time, there is a decrease in frequency and intensity of phantom pain. Persistently increased phantom pain has been seen in benign lesions affecting the peripheral and central nervous system. We present a 74-year-old woman who had a left above-knee amputation for leiomyosarcoma of the foot 24 years previously. She had been free of disease and ambulated independently until 1 month before hospitalization, when she noted increasing pain in her phantom foot. At the time of admission, she had developed increasing low back pain and was diagnosed with adenocarcinoma of unknown primary. Work-up confirmed involvement of the L4 vertebral body with epidural and paraspinal disease. We believe this is the first reported case of worsening phantom limb pain resulting from a spinal metastasis. We review the literature on the potential implications of increased phantom pain.