Thyroid lung metastasis diagnosed 47 years after thyroidectomy.

A 75-year-old woman underwent excision of a middle lobe lung nodule that contained a separate, isolated focus of metastatic papillary thyroid carcinoma. A thyroid lobectomy for papillary cancer had been performed 47 years earlier. This interval is believed to be the longest time from initial diagnosis to identification of distant lung metastasis reported. The pertinent published reports are reviewed and methods of surveillance discussed.