Unveiling the Enigma: A Peculiar Encounter of Concurrent Anti-N-methyl-D-aspartate Receptor and Anti-Hu Antibody Positive Paraneoplastic Syndrome in Small Cell Lung Cancer.

Paraneoplastic neurological syndromes (PNS) are mostly immune-mediated, tumor-associated disorders. Earlier the 2004 PNS criteria were used which are now partially outdated due to advances in PNS research and also identification of new phenotypes and antibodies that have transformed the diagnostic approach to PNS; hence, a new criterion was proposed in 2016. They can have multifarious presentations, ranging from behavioral abnormalities to altered sensorium and coma. They can precede, be synchronous with, or follow the diagnosis of malignancy. Treatment depends on the underlying antibody and malignancy. We hereby describe an unusual presentation with dual antibody positivity in a patient who was diagnosed with lung cancer in a hospital in the same presentation.