Abstract
We report a 61-year-old man with ectopic thyroid tissue in the left side of the oral floor. He had a painless and elastic hard mass suspected to be a sublingualgland tumor in the left side of the floor of the mouth. On MRI, the mass clearlyshowed low density areas on T1 and T2 images. On dynamic studies, the mass was enhanced in the early stage, suggesting a malignant tumor. On plain CT, however, the lesion was high density as compared with the muscles, and there was no thyroid gland in the normal position. Then, thyroid scintigraphy (99mTc O4-, 201T1-Cl, and 123I) was performed and confirmed that there was no uptake in the neck, but in the left side of oral floor. Thyroid function test results were within the normal range. We diagnosed the mass to be ectopic thyroid tissue. This patient was followed without treatment for about 3 years.
