Intrathyroidal Metastasis of Lung Adenocarcinoma Presenting as Subacute Thyroiditis

One of the rare diseases for differential diagnosis of subacute thyroiditis is metastases within the thyroid gland. We report here on a 72-year-old-woman with painful goiter and signs of hyperthyroidism. Her serum concentration of thyroid hormone was in the upper limit of normal, and the uptake of radioactive iodine by the thyroid was completely depressed. Although subacute thyroiditis was suspected, an additional work up that included a chest CT scan was done for the combined cough and chronic weakness. The result was lung cancer with metastatic involvement of the thyroid and multiple lymph nodes. She refused further anti-cancer therapy and died 5 months after the diagnosis. For the differential diagnosis of such a rare case, careful examination is important even in patients with the typical symptoms and laboratory findings of subacute thyroiditis.