Paraneoplastic Syndromes

Paraneoplastic syndromes (PNS) are a diverse group of systemic disorders that result from the metabolic effects of cancer in tissues distant from the tumor. They are unrelated to the size or location of the tumor, to metastasis, or to the normal physiological activities of the tissue of origin. Typically, they are caused by production and release of substances not normally released, or in amounts not normally produced, by the tumor cells. Other etiologies of PNS can include autoimmune disease, immune complex formation, immunosuppression and ectopic receptor production and/or competitive blockade for normal hormones. There are several PNSs in veterinary medicine that have been identified, many of which can cause a patient to present to a veterinary clinician on an emergency basis and may often be the first indication of the underlying neoplasia.