[Radiographic and ultrasonographic diagnosis of a left thoracic mass].

A chest roentgenogram of a 69-year-old man undergoing a check-up before prostate surgery showed a mass in the antero-inferior zone of the lung, just above the diaphragm. At ultrasonography, it was considered to be a thoracic ectopic kidney. This radiological case illustrates the place of this anomaly in the differential diagnosis of lung solitary mass, which can be explored with ultrasonography when retroperitoneal herniation is suspected.