A 62-year-old man was admitted with chief complaints of fever and general fatigue. Enhanced computed tomography revealed a tumor (5 cm in diameter) in the right suprarenal space, and the right renoportal lymph nodes were swollen. An abdominal TI-weighted MR image showed a low-intensity tumor measuring 4.5 x 5.5 x 6.0 cm. Chest computed tomography revealed two tumors. One was 1.5 cm, on the hilum of left lung, the other was 1 cm in the S6 lung field near the pleura. These findings strongly indicated primary adrenal carcinoma and lung metastasis. Right adrenalectomy was performed. Histological examination of this tumor revealed diffuse tumor cells with irregular nuclei, and it was diagnosed as poorly differentiated adenocarcinoma. There was no possibility of primary adrenal carcinoma. The primary site of the tumor was suspected to be the left lung.