Papillary Thyroid Carcinoma: Four Cases Required Caution during Long-Term Follow-Up
A 44-year-old female patient with a history of PTC was reoperated due to the PTC recurrence in a neck lymph node. The patient was diagnosed and treated 10 years prior with total thyroidectomy and high-dose RAI ablation (150 mCi). At that time, we performed the lymph node dissection in the neck as well as high-dose RAI ablation (200 mCi). During follow-up, we conducted neck sonography, measurement of thyroxin withdrawal thyroglobulin level, whole-body 131I scan, and PET-CT, but none of these tests revealed any findings of remnant PTC. However, after 1 year, follow-up chest X-ray indicated ~0.3 cm lung nodules in lung fields on both sides. The tentative diagnosis was that these were benign lesions according to the interpretation of the radiologist. Due to the patient's past history of thyroid cancer, however, we shortened the follow-up interval and took another chest CT 3 months later. The chest CT did not show any significant differences from the previous chest X-ray (). When compared with chest CT images taken 3 months later, we were able to observe slight increases in the size of the lesions. We performed a biopsy of the lung nodes by video-assisted thoracoscopic surgery, which resulted in a diagnosis of metastatic papillary thyroid cancer and bronchioloalveolar carcinoma ().