Definite PND

1. Classic syndrome with cancer diagnosed within 5 years of neurological symptom development
2. Nonclassic syndrome that resolves or significantly improves after cancer treatment
3. Nonclassic syndrome with cancer diagnosed within 5 years of neurological symptom development and positive antineuronal antibodies
4. Neurological syndrome (classic or not) without cancer and with well-characterized antineuronal antibodies

Possible PND

1. Classic syndrome with high risk of cancer, without antineuronal antibodies
2. Neurological syndrome (classic or not) without cancer and with partially characterized antineuronal antibodies
3. Nonclassic syndrome with cancer diagnosed within 2 years of neurological symptom development, without antineuronal antibodies

PND, paraneoplastic neurological disorder; CNS, central nervous system