胸内异位肾是罕见的先天性发育畸形 ,Ｘ线平片易误诊为胸内肿瘤。我院遇见 1例 ,报道如下。患者　男 ,17岁 ,因室性早搏而住院。查体 :一般情况好 ,无外伤史 ,胸廓对称 ,心率 80次 /ｍｉｎ ,早搏 5次 /ｍｉｎ ,左腹、背部未闻及血管杂音。胸片正位示左膈上纵隔旁有一成人拳头大 Thoracic ectopic kidney is a rare congenital malformations, X-ray often misdiagnosed as intrathoracic tumors. Met in our hospital in 1 case, reported as follows. Male patient, 17 years old, hospitalized for premature ventricular contractions. Physical examination: the general situation is good, no history of trauma, symmetry of the thorax, heart rate 80 beats / min, premature beats 5 times / min, left abdomen, back undulation and vascular murmur. Positive chest X-ray showed an adult fist on the left diaphragm on the mediastinum