Metastasis of pulmonary adenocarcinoma to the thyroid closely mimics papillary thyroid carcinoma.

Metastases to the thyroid gland are rare, with reported incidence as low as 0.1%. The kidney, breast, and lung are known to be the most common origins of metastatic events in the thyroid.1 It can be very challenging to distinguish metastatic tumor from primary thyroid cancer when metastatic thyroid nodules are the initial presentation of the disease. A 69-year-old woman noticed a persistent, painless mass over the right aspect of the neck. Thyroid sonography revealed a right-sided nodule measure...