Adenocarcinoma originating from presumed liver ectopic thyroid in a cat.

Case Summary: Ectopic thyroid tissue is rarely reported in dogs and cats in its prediaphragmatic location and has never been described in the liver. A 15-year-old spayed female domestic shorthair cat was diagnosed by ultrasound with a heterogeneous hypoechoic nodular area in the liver at the periphery of the quadrate lobe. A generic diagnosis of carcinoma was made after ultrasound-guided fine-needle aspiration and cytological examination.