Polyradiculopathy in leptomeningeal metastasis: the role of EMG and late response studies.

Leptomeningeal metastasis (LM) of systemic malignancy often give rise to multifocal involvement of the central (CNS) and peripheral nervous system. Signs of CNS dysfunction such as seizures and confusion often overshadow radicular deficits. We report clinical and laboratory evaluations in 10 patients with LM who presented with isolated polyradiculopathy. Our data suggest that electromyography and late response studies are sensitive indicators of radicular dysfunction in patients with LM. These studies are helpful in the early documentation of root involvement when computerized tomography, MRI and myelography are normal.