Pheochromocytomas and paragangliomas in humans and dogs.

Pheochromocytomas (PCCs) and paragangliomas (PGLs) are described in several species. In humans and dogs they have many similarities: the excessive catecholamine release in hormonally active PCC causes similar clinical signs, the frequency of metastasis is similar, and they are histopathologically almost identical. Surgery is curative when PCC and PGL have not metastasized, while only palliative treatment is possible for patients with metastatic disease. Mutations in succinate dehydrogenase subunit B (SDHB) are associated with metastatic behaviour in human PCC/PGL and the same mutation has been described in dogs. The dog might therefore be a suitable model for study of the pathogenesis of metastatic PCC and PGL in humans. Further molecular studies of common tumourigenic pathways and comparative studies of histopathology of human and canine PCC and PGL are warranted.