It is a rare spindle cell neoplasm that was initially reported in the pleura, mediastinum, and lungs. Recently, many extrathoracic locations, including kidney and retroperitoneal soft tissue, hae been described.

• 肾纤维瘤为很罕见纺锤状细胞肿瘤，常见于胸膜、纵隔和肺。近来发现该瘤也可发生于胸部以外的部位，如肾脏、腹膜后软组织等。