Overview
Paraneoplastic syndromes (PNS) are a diverse group of systemic disorders resulting from the metabolic effects of cancer in tissues remote from the tumor. These disorders are usually caused by production and release of substances not normally released by the tumor cell of origin or in amounts not normally produced by those cells. Other etiologies of PNS aside from production of metabolically active substances include autoimmune disease stimulation, immune complex formation, immunosuppression, and ectopic receptor production/competitive blockade of normal hormones. PNS may also occur secondary to substances produced by normal cells due to the presence of the tumor (e.g., tumor necrosis factor production by reticuloendothelial cells contributing to cancer cachexia). Many PNS in veterinary medicine have an unknown etiology. Pathophysiology depends on the specific PNS (see Table 1).
Signalment
Any dog or cat with a histologically malignant (most common) or benign cancer (rare)
Signs
Vary with tumor type and organ systems affected but include:
- Alopecia (feline paraneoplastic syndrome)
- Anemia
- Cachexia
- Cutaneous flushing
- Diencephalic syndrome
- Disseminated intravascular coagulation
- Eosinophilia
- Gastroduodenal ulceration
- Hypercalcemia
- Hypertrophic osteopathy
- Hypoglycemia
- Myelofibrosis
- Neutrophilic leukocytosis
- Nodular dermatofibrosis
- Polycythemia
- Superficial necrolytic dermatitis
- Thrombocytopathy
- Thrombocytopenia
- Thrombocytosis
Causes & Risk Factors
Production and release of substances not normally released by the tumor cell of origin or in amounts not normally produced by those cells and the substances' subsequent effects on target tissues.
