Paraneoplastic syndromeA 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. Unlike a mass effect, it is not due to the local presence of cancer cells. Paraneoplastic syndromes are typical among middle-aged to older patients, and they most commonly present with cancers of the lung, breast, ovaries or lymphatic system (a lymphoma).
