fused pelvic kidney

Pancake kidney (also known as discoid kidney, disc kidney, lump kidney, fused pelvic kidney or cake kidney) is a rare renal fusion anomaly of the kidneys of the crossed fused variety.

Clinical presentation

Pancake kidney may be an incidental finding. However, they can present clinically because of conditions that affect normal kidneys, such as:

• ureteropelvic junction obstruction
• recurrent infection
• recurrent calculi
• increased incidence of malignancies

Gross anatomy

The upper and lower poles of the kidneys are fused hence giving it an appearance of pancake  and usually give rise to two separate ureters which enter the bladder in a normal relationship.

An even more rare variant is when the cake kidney is drained by a single ureter (has been previously reported in only four patients) .

Pancake kidneys usually are situated anterior to the aortic bifurcation.

Radiographic features

Pancake kidney can be demonstrated on ultrasound, CT, IVU, MRI, and scintigraphy.

Treatment and prognosis

Pancake kidney malformation is not necessarily associated with renal dysfunction but does require exclusion of concomitant anomalies and long-term follow-up for early detection of possible future complications such as:

• ureteropelvic junction obstruction
• recurrent infection
• recurrent calculi
• increased incidence of malignancies
• more prone to traumatic injury

Differential diagnosis

• horseshoe kidney: usually only the lower poles are fused
• cross fused renal ectopia: kidneys lie only on one side of the spine

Siehe auch:

• angeborene renale Anomalien