Heterotropic Pulmonary Thyroid in the Presence of a Normally Located Multinodular Goitre

We report the case of a 75-year-old female with an intrapulmonary smooth, round 2-cm nodule that contained heterotrophic thyroid tissue with no malignant or teratomatous features. She also had a normally located multinodular goiter. Ultrasound examinations of the thyroid and CT-scans of the pulmonary nodule done 7 years apart showed no significant change. Thyroid/whole body scans using TC-99m done 7 years apart also provided similar findings. The lack of change in the thyroid and pulmonary nodules makes a thyroid malignancy highly unlikely. Intrapulmonary heterotrophic thyroid tissue is a very rare entity, with only 2 reported cases in the literature. Our case is different from the other 2 in that they did not have a co-existing goiter. This case report draws attention to the occurrence of intrapulmonary heterotrophic thyroid tissue. Although rare, it needs to be considered in the differential diagnoses of a pulmonary nodule.