Differential diagnosis of abnormalities of renal ascent

• Agenesis of the kidney
• Pelvic kidney
• Crossed fused renal ectopia
• Horseshoe kidney
• Intrathoracic kidney

Approach to the differential diagnosis of abnormalities of renal ascent: 

• When a kidney is either absent from its renal fossa or appears abnormally rotated in its renal fossa, the patient should be investigated for abnormalities of renal ascent
• Ultrasound is the modality of choice to look for an ectopic kidney in the pelvis and along the path of renal ascent
• If a kidney cannot be found by ultrasound and a definitive diagnosis of renal agenesis is required, DMSA renal scintigraphy or MRI of the abdomen may be use