Gallbladder carcinoid in a cat.

Carcinoids are rare tumors that originate from neuroendocrine system cells. There has apparently only been 1 report in the veterinary medical literature of a cat with a gallbladder carcinoid, with no long-term follow-up information available from that case. Furthermore, apparently only 9 dogs with gallbladder carcinoids have been reported, again with no long-term follow-up. This case report describes the clinical presentation, surgical appearance, histopathologic and immunohistochemical findings, postoperative adjuvant chemotherapy treatment, and long-term outcome of a domestic longhair cat with a gallbladder carcinoid. The diagnosis of a gallbladder carcinoid in the present case was based on histologic and immunohistochemical findings. Clinical signs of a gallbladder carcinoid are nonspecific and ultrasonographic findings may not be definitive; however, it should be considered as a potential differential diagnosis in cats with lesions of the gallbladder or in the region of the gallbladder. The prognosis is poor, with a potentially high metastatic rate. In the present case, metastasis occurred 7 mo postoperatively despite adjuvant therapy, and the survival time was only 10 mo from the time of diagnosis. Key clinical message: This case report describes the clinical presentation, surgical appearance, histopathologic and immunohistochemical findings, postoperative adjuvant treatment, and long-term outcome of a cat with a gallbladder carcinoid, which should be considered as a potential differential diagnosis in cats with lesions of the gallbladder or in the region of the gallbladder.