Thoracic kidney

Infant with

respiratory distress due to respiratory syncytial virus. CXR AP (upper left) shows a rounded mass in the left lower lobe which appears posterior in location on the CXR lateral (upper right). Coronal and axial CT with contrast of the chest (below) shows the left kidney to be in the lower left hemithorax. In the operating room, a defect at the foramen of Bochdalek was noted and repaired after the kidney had been reduced into the abdomen.The diagnosis was intrathoracic kidney due to congenital diaphragmatic hernia.

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An intrathoracic kidney is a very rare form of ectopic kidney. There has been no reported increased incidence of stones or infections as can be seen with other forms of ectopic kidneys. The adrenal glands are usually normal in location.

Epidemiology

Thoracic ectopic kidney is rare with male predominance and incidence of 1/10,000 ectopic kidneys. Left-sided intrathoracic kidney is more common .

Clinical presentation

Intrathoracic kidneys are usually asymptomatic, however in symptomatic patients presenting symptoms include pneumonia, dyspnea, and cough .

Pathology

Renal ascent to thoracic cage is limited by the diaphragm. Diaphragmatic eventration or Bochdalek hernia can lead to an intrathoracic kidney .

Radiographic features

Plain radiograph

Appears as a well-defined lower thoracic opacity.

Ultrasound

The diagnosis can be easily confirmed by ultrasound. In most cases, the thoracic kidney rests on the diaphragm, so an acoustic window of the liver or spleen can be used to demonstrate it.