A rare case of localization of a large nodus of dystopic thyroid gland with a picture of follicular colloid goiter in the upper part of the interventricular septum near the right venous ostium and valve cusps (in combination with papillary cancer of the left lobe and isthmus of the thyroid gland) in a woman of 60 is described. The patient died with a second ischemic insult and progressive cardiac insufficiency which (in the presence of atherosclerosis and hypertension) could have developed in direct connection with nodus of the thyroid gland in the interventricular septum of the right ventricle.