Paraneoplastic neurologic disorders (PNDs) are cancer-related syndromes that can affect any part of the nervous system (Table 97-1). They are remote effects of cancer, caused by mechanisms other than metastasis or by any of the complications of cancer such as coagulopathy, stroke, metabolic and nutritional conditions, infections, and side effects of cancer therapy. In 60% of patients the neurologic symptoms precede the cancer diagnosis. Overall, clinically disabling PNDs occur in –1% of all cancer patients, but they occur in 2–3% of patients with neuroblastoma or small cell lung cancer (SCLC), and in 30–50% of patients with thymoma or sclerotic.
