[A Case of Recurrent Lung Adenocarcinoma with Right Aortic Arch Treated with Pembrolizumab]

Only a few cases of primary lung cancer associated with the right aortic arch have been reported. A treatment report of recurrent lung cancer with the right aortic arch is rare. A woman in her late 70s was diagnosed with lung cancer associated with the right aortic arch. A 3.4-cm tumor was detected in the right middle lobe on CT performed before a knee joint surgery. The tumor was diagnosed as lung adenocarcinoma and categorized as cT2aN0M0 with cStage ⅠB. Subsequently, a right middle lobectomy was performed. Histopathological study revealed pT1cN1M0 with pStage ⅡB tumor. Molecular analysis revealed 85% expression of programmed death-ligand 1(PD-L1). One year after surgery, mediastinal lymph nodes recurred with multiple lung metastases. The number of metastatic lymph nodes reduced after pembrolizumab was administered, followed by the disappearance of lung metastasis. The outcome was recorded as a partial response. She has been alive 2 years after surgery.