A paraneoplastic syndrome is a syndrome (a set of signs and symptoms) that is the consequence of a tumor in the body (usually a cancerous one), specifically due to the production of chemical signaling molecules (such as hormones or cytokines) by tumor cells or by an immune response against the tumor. Peripheral neuropathy is the most common neurologic paraneoplastic syndrome. It is usually a distal sensorimotor polyneuropathy that causes mild motor weakness, sensory loss, and absent distal reflexes. Subacute sensory neuropathy is a more specific but rare peripheral neuropathy.