Paraneoplastic syndromes in dogs and cats

Paraneoplastic syndromes (PNSs) can be described as the indirect effects of tumours, typically due to tumour production and release of biologically active substances such as hormones, growth factors and cytokines. PNSs are sometimes the first evidence of a neoplastic disease; therefore, knowledge of these syndromes and their associated tumour types can help in early diagnosis. PNSs should resolve with treatment of the underlying tumour and, conversely, may return with recurrence of the underlying tumour. In some cases, they cause more significant morbidity than the tumour itself, so they must be clinically addressed for proper treatment or palliation. A further issue is that signs caused by PNSs may mimic side effects of treatment such as chemotherapy, complicating clinical decision making. This article discusses the different types of PNSs and treatment options for each case.