肺癌術後経過観察中に手術を行った胸腺癌の1例

Thymic Carcinoma Operated After Lung Cancer Operation：Report of a Case

はじめに　原発性肺扁平上皮癌と胸腺扁平上皮癌の同時重複癌はまれな疾患である．組織型が同じであるが，免疫染色で転移ではなく肺癌と胸腺癌の重複癌と診断した．また剣状突起下アプローチにより，胸腔内の癒着の影響が比較的少なく胸腺全摘を行えたため報告する．

A 70-year-old man presented with the growth of an anterior mediastinal nodule on a follow-up computed tomography （CT） scan after undergoing lung cancer surgery. Positron emission tomography （PET）-CT performed at the time of lung cancer surgery did not recognize any accumulation, but PET-CT performed this time confirmed the accumulation of standardized uptake value （SUV） max 5.57. As a result, we suspected a recurrence of lung cancer and the occurrence of an anterior mediastinal tumor. Therefore, we performed surgery for both resection and diagnostic purposes. Total thymus removal was performed using a subxiphoid approach. The tumor was diagnosed to be thymic squamous cell carcinoma because the immunostaining for CD5 and CD117 was positive. The same type of carcinoma was recognized as a small nodule during the previous lung cancer surgery, and it is considered to represent a synchronous double cancer.