多結節性甲状腺腫を呈し転移の可能性を伴う乳頭癌：症例報告

Multinodular goiter (MNG), which may be caused by a variety of risk factors, is typically incidentally found. It is not uncommon for an incidental finding of MNG to lead to a diagnosis of papillary thyroid carcinoma (PTC); however, close monitoring for metastasis is necessary in high-risk patients. Herein, we present the case of a 71-year-old male, seemingly following a normal path of incidental discovery of MNG leading to PTC upon thyroid ultrasound and fine-needle aspiration (FNA) biopsy diagnostic exams. A total thyroidectomy was performed, with pathology confirming an aggressive tumor type (tall cell variant, T4a). Postoperative findings revealed extrathyroidal extension (ETE) with possible lung metastasis. Complications such as these highlight the importance of closely monitoring patients with a higher risk of aggressive thyroid cancer.