Canine paraganglioma: a case report

An 8-year-old castrated Cocker Spaniel with tympanic paraganglioma was presented. The tumour was resected twice with an interval of 120 days. The dog presented with tetraparesis 130 days after the second operation and had radiologic evidence of metastasis to the C5 vertebra. On pathologic examination, metastasis of the tumour was found in the myocardium, lungs, kidney, and C5 vertebra. The tumour, which is being described for the first time in the dog, was highly vascular, and was characterized by various-sized groups of medium-sized cells separated by vascular stroma. The neoplastic cells were round or polyhedral with moderately hyperchromatic nuclei, scattered chromatin, indistinct nucleoli, and eosinophilic granular cytoplasm. The metastatic lesions were histologically similar to the primary tumour.