Abstract
Two cases of papillary thyroid carcinoma with solitary lung metastasis are reported. Case 1 : A 73-year-old woman was found to have a round, well-defined, solitary tumor shadow in S10c of the left lung on pulmonary CT on a regular follow-up examination following rectal cancer surgery. Thoracoscopic partial lung resection was performed, and the patient was diagnosed with lung metastasis of papillary thyroid carcinoma on histopathological examination. The patient subsequently underwent total thyroidectomy and radioactive iodine therapy. She has remained relapse-free for 10 years postoperatively. Cases 2 : A 52-year-old woman, after having undergone total thyroidectomy for papillary thyroid carcinoma at the age of 50 years, underwent thoracoscopic resection two years later for a solitary lung nodule that had been simultaneously detected ; the nodule was histopathologically diagnosed as papillary thyroid carcinoma. Radioactive iodine therapy was then given, and the patient has remained relapse-free for eight years. Metastases of papillary thyroid carcinoma usually present as multiple nodules or in a miliary pattern.
Although solitary lung metastasis is very rare, it is important to consider atypical cases such as those described above. In cases of lung metastases presenting as large nodules, resection is recommended for the purposes of both diagnosis and treatment because radioactive iodine therapy alone may be insufficient.
