Carcinoma of Ectopic Thyroid in a Dog

Walsh KM, Diters RW.

Journal of American Animal Hospital Association 1984;20:665-668.

The differential diagnoses for heart base mass include aortic body chemodectoma, ectopic thyroid tumor, ectopic parathyroid tumor, mesothelioma, cardiac myxoma, and lymphadenopathy. The inci- dence of ectopic thyroid neoplasms at the heart base in dogs is not known but is suggested to be 5%to 10%of all heart base masses.1 In one report, 7 of 40 heart base tumors were diagnosed as thyroid carcinomas .2 Presenting signs of dogs with heart base tumors include dys- phagia, dyspnea,3 and signs suggestive of cardiac failure such asdis- tention of cervical veins. Radiographic evidence of a heart base mass together with signs of endocrinopathy should be followed by scintig- raphy4 and/or thyroid function tests to support the diagnosis of ec- topic thyroid tumor.This report describes a carcinoma of ectopic thyroid tissue at the heart base in a dog.