Metastatic neuroendocrine carcinoma of aortic body origin in a cat.

An 8-year-old, female spayed Domestic Shorthair cat was presented to the Auburn University Emergency and Critical Care service for evaluation of pleural effusion and a suspected intrathoracic mass. Computed tomography was performed which confirmed the presence of a large intrathoracic mass, likely heart-based. Fine-needle aspirates were obtained and a cytologic diagnosis of a neuroendocrine tumor was made. Treatment with toceranib phosphate was briefly attempted at home by the owners. The cat died at home approximately 6 weeks after diagnosis. Necropsy and subsequent histopathologic examination revealed a metastatic neuroendocrine carcinoma of aortic body origin. Aortic body tumors are extremely rare in cats and to the authors' knowledge, a neuroendocrine carcinoma of aortic body origin with distant metastases has not yet been reported in a cat.