肺癌手術を契機に上縦隔リンパ節転移で発見された不顕性甲状腺癌

Occult Thyroid Cancer Diagnosed by Metastasis to an Upper Mediastinal Lymph Node Removed during Surgery for Primary Lung Cancer

肺癌の外科治療において，手術を契機として偶発的に他臓器の不顕性癌が見つかることがある．われわれは肺癌手術時に上縦隔リンパ節転移で発見された不顕性甲状腺癌の1例を経験したので報告する．

A computed tomography （CT） scan revealed 2 nodules in the right upper and middle lobes of the lung and swelling of an upper mediastinal lymph node （#2R） in a 77-year-old male. Positron emission tomography （PET）/CT showed abnormal uptake only in the right middle lobe nodule, so we suspected a double primary lung cancer （cT1bN0M0, stageⅠA）, and performed a right upper and middle lobectomy with ND2a-2 dissection. Pathological investigation revealed that the lung nodules were adenocarcinomas and the lymph node swelling #2R was a metastasis of thyroid cancer. After surgery, careful examination was done for thyroid but the primary lesion was not found. Careful observation for an occult thyroid cancer is continuing at the outpatient.