Figure 1
CT with 3-D reconstruction abdomen and pelvis
CT with 3-D reconstruction demonstrates a malrotated right kidney with an anterior-facing renal hilum and its relation with the ureter and pelvis.
A complication of renal malrotation
SectionUroradiology & genital male imaging
Case TypeClinical Cases
AuthorsCheng X, Hawthorn B, Huang D
Connected authors
52 years, male
Clinical History
A fit, 52-year-old man presented with a 3-month history of recurrent right flank pain without lower urinary tract symptoms or haematuria. On assessment, his urine dipstick was positive for nitrates. He was seen in urology outpatient department and underwent imaging.
Imaging Findings
A renal tract ultrasound was performed initially which demonstrated an abnormal right kidney with a hyper-echoic area measuring 2.3 cm in the lower pole. The left kidney was normal.
Renal DMSA confirmed there was some irregularity with deficiency towards the right upper renal pole. Relative renal function was 77% on the left and 23% on the right.
A triple phase CT of the kidneys and urinary tract reveals right renal malrotation in a reverse rotation fashion with renal hilum and ureter facing anterolaterally. Multiple renal vessels were also located anteriorly. There was ipsilateral pelvi-ureteric junction obstruction as well as an 18x22mm calculus within the dilated right renal pelvis.
Renal DMSA confirmed there was some irregularity with deficiency towards the right upper renal pole. Relative renal function was 77% on the left and 23% on the right.
A triple phase CT of the kidneys and urinary tract reveals right renal malrotation in a reverse rotation fashion with renal hilum and ureter facing anterolaterally. Multiple renal vessels were also located anteriorly. There was ipsilateral pelvi-ureteric junction obstruction as well as an 18x22mm calculus within the dilated right renal pelvis.
Discussion
The ureteric bud and metanephric mass of the intermediate mesoderm fuse during the 4th week of gestation and as the kidneys develop, they ascend from the first or second sacral segment to the lumbar region. As they migrate upwards in the body, the kidneys move apart and rotate medially by 90 degrees so the hila are located anteromedially. They achieve their final position by the 9th week of gestation.
When the kidney fails to rotate or over-rotates, this is known as malrotation and can affect one or both kidneys. Malrotation occurs in 1 in 939 autopsies and can be divided into non-rotation, incomplete rotation, reverse rotation, transverse rotation or excessive rotation [1]. Non-rotation and incomplete rotation are most commonly seen [2, 3]. In those suffering from Turner’s syndrome, there is a higher incidence of malrotation. One study looking into 82 patients with Turner’s syndrome found 16.1% prevalence [4].
There are no specific complications linked with renal malrotation, however, some studies have described higher occurrence of renal calculi associated with hydronephrosis as well as urinary tract infections secondary to urine stasis. In a study looking at patients with renal anomalies, it was found that 3 out of 4 patients who had malrotation also had renal calculi and 2 had UTIs [5]. A rare case of renal cell carcinoma in a horizontally rotated kidney has been described but is not an established complication for renal malrotation [1].
Renal orientation can be difficult to be fully established on ultrasound examination alone and the unusual renal orientation in renal malrotation may lead to misinterpretation of the sonographic findings. Cross-sectional imaging with multi-planar reformat allows confident establishment of the diagnosis. In 20-30% of patients with malrotation, multiple renal arteries have been found on imaging and this presents a risk of vascular injury during operations, therefore there may be value of performing pre-operative CT angiography [6].
When the kidney fails to rotate or over-rotates, this is known as malrotation and can affect one or both kidneys. Malrotation occurs in 1 in 939 autopsies and can be divided into non-rotation, incomplete rotation, reverse rotation, transverse rotation or excessive rotation [1]. Non-rotation and incomplete rotation are most commonly seen [2, 3]. In those suffering from Turner’s syndrome, there is a higher incidence of malrotation. One study looking into 82 patients with Turner’s syndrome found 16.1% prevalence [4].
There are no specific complications linked with renal malrotation, however, some studies have described higher occurrence of renal calculi associated with hydronephrosis as well as urinary tract infections secondary to urine stasis. In a study looking at patients with renal anomalies, it was found that 3 out of 4 patients who had malrotation also had renal calculi and 2 had UTIs [5]. A rare case of renal cell carcinoma in a horizontally rotated kidney has been described but is not an established complication for renal malrotation [1].
Renal orientation can be difficult to be fully established on ultrasound examination alone and the unusual renal orientation in renal malrotation may lead to misinterpretation of the sonographic findings. Cross-sectional imaging with multi-planar reformat allows confident establishment of the diagnosis. In 20-30% of patients with malrotation, multiple renal arteries have been found on imaging and this presents a risk of vascular injury during operations, therefore there may be value of performing pre-operative CT angiography [6].
Differential Diagnosis List
Obstructive uropathy and urolithiasis in a malrotated kidney
Urolithasis in a non-rotated kidney
Renal cell carcinoma
Crossed fused renal ectopia
Final Diagnosis
Obstructive uropathy and urolithiasis in a malrotated kidney
References
[1] Lim TJ et al. (2011) Renal cell Carcinoma in a Right Malrotated Kidney. Korean J Urol 52:792-794 (PMID: 22195271)
[2] Daneman A, Alton DJ (1991) Radiographic manifestations of renal anomalies. Radiol Clin North Am 29(2):351-363 (PMID: 1998056)
[3] Nino-Murcia M, deVries PA and Friedland GW. (2000) Congential anomalies of the kidneys. In: Pollack HM. Jr. McClennan BL, eds. Clinical urography 2nd edition. Philadelphia: Saunders 690-763
[4] Bilge I et al. (2000) Frequency of renal malformations in Turner’s syndrome: analysis of 82 Turkish children. Pediatr Nephrol 14:1111-1114 (PMID: 11045397)
[5] Muttarak M and Sriburi T (2012) Congenital renal anomalies detected in adulthood. Biomed Imaging Interv J 8(1):e7 (PMID: 22970063)
[6] Patrizi L et al. (2013) Congenital renal malrotation in ovarian cancer surgery: a case report. Gynecologic Oncology Reports 41-43 (PMID: 24371669)
Case information
| URL: | https://www.eurorad.org/case/13083 |
| DOI: | 10.1594/EURORAD/CASE.13083 |
| ISSN: | 1563-4086 |
License
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Figure 2
Post-contrast axial CT abdomen
Axial CT image demonstrates a malrotated right kidney containing a large renal calculus.
Figure 3
Post-contrast CT coronal
Coronal CT demonstrates a malrotated right kidney containing a large renal calculus.
Figure 4
Post-contrast CT sagittal
Sagittal CT image demonstrates a malrotated right kidney with a large calculus within the dilated right renal pelvis.
CT with 3-D reconstruction abdomen and pelvis
CT with 3-D reconstruction demonstrates a malrotated right kidney with an anterior-facing renal hilum and its relation with the ureter and pelvis.
Huang, D. Department of Radiology, King\'s College Hospital, London U.K.
Huang, D. Department of Radiology, King\'s College Hospital, London U.K.
Post-contrast axial CT abdomen
Axial CT image demonstrates a malrotated right kidney containing a large renal calculus.
Hawthorn, B. King\'s College Hospital, London
Hawthorn, B. King\'s College Hospital, London
Post-contrast CT coronal
Coronal CT demonstrates a malrotated right kidney containing a large renal calculus.
Hawthorn B. Department of Radiology, King\'s College Hospital, London. UK.
Hawthorn B. Department of Radiology, King\'s College Hospital, London. UK.
Post-contrast CT sagittal
Sagittal CT image demonstrates a malrotated right kidney with a large calculus within the dilated right renal pelvis.
Hawthorn B, Department of Radiology, King\'s College Hospital, London, UK.
Hawthorn B, Department of Radiology, King\'s College Hospital, London, UK.