A rare case of an ectopic thyroid gland in the porta hepatis and in the tongue in an asymptomatic euthyroid 24-year-old woman is reported. A solitary inhomogeneous, hypoechogenic and hyperechogenic mass in the porta hepatis was accidentally discovered by ultrasonography. Subsequent computed tomography demonstrated a heterogeneous, well-defined tumor with small calcifications without signs of environmental invasion. A hemangioma and focal nodular hyperplasia were excluded by blood pool and hepatobiliary scintigraphy. Surprisingly, fine-needle aspiration cytology revealed normal thyroid tissue. (123)I-scintigraphy confirmed the presence of ectopic dual thyroid tissue in the hepatic porta and lingua. At clinical inspection the lingual thyroid gland was palpable and visible, and appeared solid and spheroidal. The subhepatic, ectopic thyroid mass was resected. Postoperatively, thyroid hormone replacement was started to prevent an enlargement of the lingual thyroid. Today, 4 years after surgery, the patient remains euthyroid.