Hipotireoidismo primário decorrente de carcinoma de tireoide em um felino: relato de caso

Abstract

Hypothyroidism is commonly diagnosed in dogs and rarely found in cats. In felines it develops mainly iatrogenically, as after treatment of hyperthyroidism with high dose of antithyroid. Hypothyroidism in felines in the primary mode due to thyroid neoplasm is extremely rare. This monograph aims to report the case of a feline of thirteen years with a history of volume increase in bilateral cervical region for one year that had grown massively two weeks prior to the animal’s admission. The cat presented dysphonia, lethargy, weight gain and constipation. At the physical exam hypothermia was observed with rectal temperature of 36,5ºC. Fine needle aspiration cytology suggested thyroid neoplasia. The serum dosage of total T4 and TSH along with the exclusion of non-thyroid diseases confirmed the diagnosis of hypothyroidism. This is the first report of feline hypothyroidism in Brazil due to thyroid neoplasia, classified as a follicular-compact carcinoma, confirmed with histopathology.