A paraneoplastic syndrome is a syndrome (a set of signs and symptoms) that is the consequence of cancer in the body, specifically due to the production of chemical signalling 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). [Source: Wikipedia ]