Neuromuscular disorders in systemic malignancy and its treatment.

Neuromuscular dysfunction in patients with known or suspected malignancy has three basic etiologies: (1) a direct effect of the neoplasm, either by compression or infiltration; (2) a "remote," or paraneoplastic, effect of cancer; or (3) a side effect of anticancer treatment, radiation or chemotherapy. A variety of clinical features or syndromes are due to damage either at the level of the neuron (anterior horn cell or dorsal root ganglion neuron), nerve root(s), brachial or lumbosacral plexus, peripheral nerve (motor, sensory, and/or autonomic), neuromuscular junction, or muscle. A complex clinical picture evolves when dysfunction in due to more than one cause at more than one anatomical site.