Neurologic aspects of monoclonal gammopathy of undetermined significance, multiple myeloma, and related disorders

Radiculopathy is the single most frequent neurologic complication of multiple myeloma. It usually involves the thoracic or lumbosacral area, and results from compression of the nerve root by a paravertebral plasmacytoma or by the collapsed bone itself. Compression of the spinal cord from an extramedullary plasmacytoma occurs in 5% of patients with myeloma during the course of their disease. Rarely, myeloma cells diffusely infiltrate the meninges. Intracranial plasmacytomas most commonly arise in the base of the skull and represent myelomatous lesions from bone. Softtissue plasmacytomas of the central nervous system are rare. Peripheral sensorimotor peripheral neuropathy is uncommon in multiple myeloma; when present, it is usually caused by amyloidosis or osteosclerotic myeloma.