術後17年目を経て転移・再発を繰り返した後に未分化転化した甲状腺乳頭癌の1例

Anaplastic transformation of papillary thyroid carcinoma with recurrence in upper mediastinal lymph nodes

はじめに

　甲状腺乳頭癌は高い治癒率が得られているが，10年生存率が議論されるように長期の経過観察が肝要といわれている。

　われわれは甲状腺右葉乳頭腺癌の術後，17年目に嗄声をきたし，CTで甲状腺左葉に異常陰影，甲状腺左葉直下と腕頭動脈直下のリンパ節腫脹が認められ，それらを頸部創部から摘出しえた症例を経験した。しかし，その後に転移・再発を繰り返し，初回の転移巣切除から7年の経過を経て縦隔リンパ節転移巣は未分化転化を示したので文献的考察を加え報告する。

　A 64-year-old male presented with past history of right subtotal thyroidectomy for papillary thyroid carcinoma before 17 years. We performed thyroidectomy for the remaining left lobe with dissection of metastatic lymph nodes in the neck and adjacent to the brachiocephalic artery by cervical approach. However, lymph node metastases recurred in the neck and upper mediastinum. Histopathological examination of dissected lymph nodes from recurrent metastases 7 years later showed that the lesion in the cervical lymph node was well-differentiated papillary carcinoma, while the mediastinal lymph nodes was anaplastic carcinoma. We would like to emphasize the probability of anaplastic transformation of papillary thyroid carcinoma with repeated recurrence even in a metastatic focus, and the importance of careful examination.