Pancake kidney

Changed by Mostafa Elfeky, 30 Jan 2023
Disclosures - updated 11 May 2022: Nothing to disclose

Updates to Article Attributes

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Pancake kidney (also known as discoid kidneydisc 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:

Gross anatomy

The upper and lower poles of the kidneys are fused hence giving it an appearance of pancake 5 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) 5.

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:

Differential diagnosis

  • -<p><strong>Pancake kidney </strong>(also known as <strong>discoid kidney</strong>, <strong>disc kidney</strong>, <strong>lump kidney</strong>, <strong>fused pelvic kidney </strong>or <strong>cake kidney</strong>) is a rare <a href="/articles/congenital-renal-anomalies">renal fusion anomaly</a> of the <a href="/articles/kidneys">kidneys</a> of the crossed fused variety.</p><h4>Clinical presentation</h4><p>Pancake kidney may be an incidental finding. However, they can present clinically because of conditions that affect normal kidneys, such as:</p><ul>
  • -<li><a href="/articles/pelviureteric-junction-obstruction-1">ureteropelvic junction obstruction</a></li>
  • -<li>recurrent infection</li>
  • -<li>recurrent <a href="/articles/urolithiasis">calculi</a>
  • -</li>
  • -<li>increased incidence of <a href="/articles/renal-tumours">malignancies</a>
  • -</li>
  • -</ul><h4>Gross anatomy</h4><p>The upper and lower poles of the kidneys are fused hence giving it an appearance of pancake <sup>5</sup> and usually give rise to two separate <a href="/articles/ureter">ureters</a> which enter the <a href="/articles/urinary-bladder">bladder</a> in a normal relationship. </p><p>An even more rare variant is when the cake kidney is drained by a single ureter (has been previously reported in only four patients) <sup>5</sup>.</p><p>Pancake kidneys usually are situated anterior to the aortic bifurcation.</p><h4>Radiographic features</h4><p>Pancake kidney can be demonstrated on ultrasound, CT, IVU, MRI, and scintigraphy.</p><h4>Treatment and prognosis</h4><p>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:</p><ul>
  • -<li><a href="/articles/pelviureteric-junction-obstruction-1">ureteropelvic junction obstruction</a></li>
  • -<li>recurrent <a title="Pyelonephritis" href="/articles/pyelonephritis">infection</a>
  • -</li>
  • -<li>recurrent <a href="/articles/urolithiasis">calculi</a>
  • -</li>
  • -<li>increased incidence of <a href="/articles/renal-tumours">malignancies</a>
  • -</li>
  • -<li>more prone to <a title="Renal trauma" href="/articles/renal-trauma-1">traumatic injury</a>
  • -</li>
  • -</ul><h4>Differential diagnosis</h4><ul>
  • -<li>
  • -<a href="/articles/horseshoe-kidney">horseshoe kidney</a>: usually only the lower poles are fused</li>
  • -<li>
  • -<a href="/articles/crossed-fused-renal-ectopia">cross fused renal ectopia</a>: kidneys lie only on one side of the spine</li>
  • +<p><strong>Pancake kidney </strong>(also known as <strong>discoid kidney</strong>, <strong>disc kidney</strong>, <strong>lump kidney</strong>, <strong>fused pelvic kidney </strong>or <strong>cake kidney</strong>) is a rare <a href="/articles/congenital-renal-anomalies">renal fusion anomaly</a> of the <a href="/articles/kidneys">kidneys</a> of the crossed fused variety.</p><h4>Clinical presentation</h4><p>Pancake kidney may be an incidental finding. However, they can present clinically because of conditions that affect normal kidneys, such as:</p><ul>
  • +<li><a href="/articles/pelviureteric-junction-obstruction-1">ureteropelvic junction obstruction</a></li>
  • +<li>recurrent infection</li>
  • +<li>recurrent <a href="/articles/urolithiasis">calculi</a>
  • +</li>
  • +<li>increased incidence of <a href="/articles/renal-tumours">malignancies</a>
  • +</li>
  • +</ul><h4>Gross anatomy</h4><p>The upper and lower poles of the kidneys are fused hence giving it an appearance of pancake <sup>5</sup> and usually give rise to two separate <a href="/articles/ureter">ureters</a> which enter the <a href="/articles/urinary-bladder">bladder</a> in a normal relationship. </p><p>An even more rare variant is when the cake kidney is drained by a single ureter (has been previously reported in only four patients) <sup>5</sup>.</p><p>Pancake kidneys usually are situated anterior to the aortic bifurcation.</p><h4>Radiographic features</h4><p>Pancake kidney can be demonstrated on ultrasound, CT, IVU, MRI, and scintigraphy.</p><h4>Treatment and prognosis</h4><p>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:</p><ul>
  • +<li><a href="/articles/pelviureteric-junction-obstruction-1">ureteropelvic junction obstruction</a></li>
  • +<li>recurrent <a title="Pyelonephritis" href="/articles/pyelonephritis">infection</a>
  • +</li>
  • +<li>recurrent <a href="/articles/urolithiasis">calculi</a>
  • +</li>
  • +<li>increased incidence of <a href="/articles/renal-tumours">malignancies</a>
  • +</li>
  • +<li>more prone to <a title="Renal trauma" href="/articles/renal-trauma-1">traumatic injury</a>
  • +</li>
  • +</ul><h4>Differential diagnosis</h4><ul>
  • +<li>
  • +<a href="/articles/horseshoe-kidney">horseshoe kidney</a>: usually only the lower poles are fused</li>
  • +<li>
  • +<a href="/articles/crossed-fused-renal-ectopia">cross fused renal ectopia</a>: kidneys lie only on one side of the spine</li>
Images Changes:

Image 5 MRI (T2) ( create )

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