Patients with PNDs typically exhibit rapidonset, severe, and focal neurologic disease on
initial examination. Magnetic resonance imaging findings are usually normal, and medical
history and physical examinations yield no obvious cause for the disorders. An occult
malignancy is usually discovered as patients are followed up or when a PND diagnosis is
suspected. It is believed that such malignancies underlie the neurologic degeneration in
PNDs. More specifically, breast, ovarian, or small cell lung cancer (or sometimes other tumor …