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CASE REPORT
Year : 2021  |  Volume : 48  |  Issue : 2  |  Page : 102-106

A rare case of horseshoe kidney with unilateral chronic pyelonephritis in a cadaver


1 Department of Anatomy, Jawaharlal Nehru Medical College, KLE Academy of Higher Education and Research, Belagavi, Karnataka, India
2 Department of Pathology, Jawaharlal Nehru Medical College, KLE Academy of Higher Education and Research, Belagavi, Karnataka, India
3 Department of Surgery, Jawaharlal Nehru Medical College, KLE Academy of Higher Education and Research, Belagavi, Karnataka, India

Date of Submission19-May-2021
Date of Acceptance29-Jun-2021
Date of Web Publication18-Aug-2021

Correspondence Address:
Sheetal Vishwanath Pattanshetti
Department of Anatomy, Jawaharlal Nehru Medical College, KLE Academy of Higher Education and Research, Belagavi, Karnataka
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jss.jss_59_21

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  Abstract 


Horseshoe kidney is one of the most common congenital urologic anomalies, with an incidence of 1 in 400 live births. The presence of this type of fusion anomaly of kidneys with resultant progression to renal pathology sometimes may remain obscured or dormant, due to the person being asymptomatic for years, only to be incidentally encountered during an autopsy, or during a cadaveric dissection. Similarly, during routine cadaveric dissection, we came across with a list of variations along with congenital anomalous horseshoe kidney. In this case report, we discuss about anatomical variation and pathological findings of horseshoe kidney.

Keywords: Anomalies, cadaveric dissection, horseshoe kidney, pyelonephritis, renal development, VACTERL


How to cite this article:
Balasubramanian R, Pattanshetti SV, Kangle R, Gosavi M, Srevatsa K, Virupaxi RD, Pattanshetti VM. A rare case of horseshoe kidney with unilateral chronic pyelonephritis in a cadaver. J Sci Soc 2021;48:102-6

How to cite this URL:
Balasubramanian R, Pattanshetti SV, Kangle R, Gosavi M, Srevatsa K, Virupaxi RD, Pattanshetti VM. A rare case of horseshoe kidney with unilateral chronic pyelonephritis in a cadaver. J Sci Soc [serial online] 2021 [cited 2021 Dec 6];48:102-6. Available from: https://www.jscisociety.com/text.asp?2021/48/2/102/324079




  Introduction Top


The incidence of horseshoe kidney, reported to be 1 in 400 live births, is found to be frequently encountered among the congenital anomalies of the urological system.[1] However, its occurrence as a fusion anomaly progresses subsequently in due course of life into renal pathology which may sometimes be obscured or dormant, being asymptomatic for years, sometimes, only to be diagnosed after the person is deceased. However, the underlying dormant disease may have manifestations due to anomalous relation of the renal pelvis and ureter which invariably leads to stagnation of urine, resultant calculus formation, recurrent acute or chronic hydronephrosis, or sometimes long-standing chronic infections, pyelonephritis, and rarely neoplasms. Due to advances in radiological imaging techniques, this anomaly can be diagnosed at a much earlier stage and requires surgical treatment which can prevent the patient succumbing to life-threatening complications.

The embryological basis of the anomaly, details of pathological report, and possible surgical procedures in its management is being discussed in the case report.


  Case Report Top


During routine cadaveric dissection in the department of anatomy, a female cadaver aged around 65 years showed a list of variations, namely mesocolon for the cecum and ascending colon [Figure 1] and [Figure 2], congenital anomalous horseshoe kidney [Figure 3] with variable renal hilar anatomy, two renal calculi [Figure 4] and [Figure 5], multiple renal arteries supplying right kidney, two left ovarian veins draining separately into left renal vein [Figure 6], right ovarian vein draining into the right renal vein [Figure 6], and bilateral streak ovaries. There was a horseshoe-shaped kidney in which the left and the right kidneys were joined at the lower pole forming an isthmus and the ascent of it was restricted by the inferior mesenteric artery [Figure 3]. The right kidney was covered by excess perirenal fat deposit of thickness of 2 cm, both anteriorly and posteriorly [Figure 3]. The left kidney had normal fat in the perirenal region. The hilum of the left kidney was medial. There was also variation in the vascular anatomy in the specimen [Figure 7].
Figure 1: Horseshoe kidney with mesenteric folds of the intestine (arrow)

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Figure 2: Cecum and ascending colon with retained peritoneal fold (arrow)

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Figure 3: In situ congenital anomalous horseshoe kidney with isthmus and inferior mesenteric artery (hooked by dissecting instruments)

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Figure 4: Coronal cut section through horseshoe kidney showing one calculous at isthmus (arrow) and another at the right inferior renal pelvis (arrow). Right kidney showing dilated pelvi-calyceal system with loss of renal parenchyma

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Figure 5: Staghorn renal calculus in the right inferior renal pelvis (arrow)

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Figure 6: In the specimen, two left ovarian veins (arrowheads) draining separately into the left renal vein and right ovarian vein (arrow) draining into the right renal vein are seen

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Figure 7: Arterial supply of horseshoe kidney (arrow)

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There were two calculi found in the horseshoe kidney. One was at the isthmus and another was at the right renal pelvis. The latter was staghorn calculus. There were hydronephrosis and a lot of pus collection in the right renal pelvis as well as loculated deposits of pus which had destroyed the right side renal parenchyma. Interestingly, there was no spread of infection to the other side and even the isthmus appeared parenchymatous and normal.

The specimen of horseshoe kidney was subjected to pathological examination. The pathological report was as follows:

Anatomical findings

The received specimen of horseshoe kidney was fused at the lower pole. The right kidney measured 12.5 cm × 5.9 cm × 5.6 cm. The left kidney measured 11.9 cm × 4.9 cm × 3.7 cm. The isthmus measured 3.2 cm × 2.9 cm × 1.7 cm. On cut section, the right kidney showed the presence of staghorn renal calculi measuring 5 cm × 2 cm × 1 cm in the inferior renal pelvis. Another calculus was at isthmus 1 cm × 0.9 cm × 0.8 cm. The pelvi-calyceal system was dilated with destruction of renal parenchyma. The left kidney appeared normal.

Histopathological findings

Section studied from the affected kidney shows [Figure 8] hyalinization of the glomeruli and thyroidization of the tubules. The interstitium showed fibrosis and chronic inflammatory cells. There was no evidence of malignancy in the section studied. Section from the other kidney was within normal limits.
Figure 8: Histopathology of the right kidney showing hyalinization of the glomeruli (arrowhead) and thyroidization of the tubules (arrow)

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Impression

Horseshoe kidney: Features of chronic pyelonephritis of right kidney.


  Discussion Top


In the present case, the renal vascularity also showed some variations. The left renal vein was formed by four tributaries, of which two were anterior and two were posterior. The two anterior veins were anterior to all structures in the hilum and the two posterior veins were in between pelvis and renal artery. The left renal artery originated as a lateral branch of the descending part of the abdominal aorta, 2 cm below the origin of the superior mesenteric artery. The artery divided into an anterior and posterior branch at the upper pole of the left kidney and entered the hilum. The arrangement of structures in the hilum from anterior to posterior were two anterior tributaries of renal vein and renal pelvis and two posterior tributaries of renal vein and renal artery. Two left gonadal veins (medial and lateral) drained into the left renal vein inferiorly. A suprarenal vein drained into the renal vein superiorly, which was in line with the medial gonadal vein.

The right kidney was covered by excess perirenal fat and the hilum was anterior. There were three arteries supplying the right kidney. One was from the lumbar artery 0.5 cm above the bifurcation of the aorta and two renal arteries (superior and inferior) from the aorta as a lateral branch at the level of the superior mesenteric artery. The lumbar artery which entered in the lower part of the posterior surface of the right kidney supplying the lower pole was probe patent. The superior renal artery was completely stenosed by excessive proliferation of the tunica media. The inferior renal artery was patent. The right renal vein drained into the inferior vena cava. The right suprarenal vein drained in the right renal vein superiorly and the right ovarian vein traveled along the convex border of the right kidney and drained into the inferior surface of the right renal vein. The right pelvis was dilated. The arrangement of structures in the hilum of the right kidney were as follows, superiorly renal vein and renal artery; inferiorly the renal pelvis. The renal vein was anterior to the renal artery. There was also significant calcification noticed at the superior vesical artery (Mönckeberg's arterial sclerosis).

There can be variations in the position of the horseshoe kidney which could be encountered to be arrested in its ascent, anywhere from its normal position in the lumbar to the pelvic regions. Some of the other findings could be minimal dilatation of the pelvi-calyceal system but seldom hydroureter or hydronephrosis secondary to stenosis of pelvi-ureteral system or luminal occlusion due to kinking of the ureter at the point where it crosses the isthmus, renal calculus formation, and abnormalities in the renal vasculature or sometimes could be abnormal arterial supply, for example, arising from the mesenteric artery.[2]

In our case, however, there was hydronephrosis and a lot of pus collection in the right renal pelvis. There were multiple loculated deposits of pus which had destroyed the right side renal parenchyma. Interestingly, there was no spread of infection to the other side and even the isthmus appeared parenchymatous and normal. The left kidney appeared normal.

In a study conducted by Lippe et al. on 141 Turner's syndrome patients, they encountered 47 (33%) patients who had congenital renal anomaly, out of which 11 were horseshoe kidney.[3] According to another study, there was no case of horseshoe kidney with unilateral chronic pyelonephritis reported in the literature which they reviewed, though there was a horseshoe kidney reported which stated unilateral emphysematous pyelonephritis, which is found to be bilateral in only 10% of the cases.[4]

The most common malignancy in horseshoe kidney is renal cell carcinoma; still, its incidence remains same as that in normal kidney. Among the renal neoplasms, transitional cell cancer and sarcoma amount to 20% and 7%, respectively. Due to the underlying pathologies such as chronic obstruction, calculi, and pyelonephritis in the affected kidneys, there is an increase in the risk by 3–4 times of developing transitional cell carcinoma in the horseshoe kidney. There is a two times greater incidental risk of Wilms tumor arising from the isthmus.[5]

In a study of case series of rare renal carcinoids with 32 reported cases, 5 of these renal carcinoids arose in a horseshoe kidney, of which 3 arose from or involved isthmus. The relative risk of a carcinoid tumor in horseshoe kidney patients was 62 times compared to that in normal population.[6] In our case, though we encountered much difficulty in resection of the specimen en bloc with us presuming, the reason could be possibly, due to malignancy, but it was actually due to chronic inflammation and dense adhesions with no evidence of malignancy histopathologically. Section from the other kidney was within normal limits.

Horseshoe kidneys are often associated with various congenital malformations that may or may not be necessarily confined to genitourinary systems but could be sometimes even encountered as a component of various syndromes like chromosomal/aneuploidic anomalies such as Down's syndrome, Turner's syndrome, Edwards' syndrome, and Patau's syndrome. The nonaneuploidic anomalies associated with horseshoe kidney are Ellis-van Creveld syndrome, Fanconi anemia, Goltz syndrome, Kabuki syndrome, Pallister-Hall syndrome, and VACTERL association.[7]

Embryological evidence

The cells from the posterior nephrogenic area of the epiblast form a parenchymal structure of isthmus of horseshoe kidney in-turn which forms an incomplete or abnormal migration across the primitive streak and persist in the mid-line to form an isthmus of the horseshoe kidney. When compared to cases wherein there is a fibrous isthmus connecting the two kidneys, a close approximation of the metanephroi to the medial line is most possibly would have occurred, resulting in a fibrous tissue isthmic band arising from mesenchyme interposed between the metanephroi.[8]

The most conventional view was that in their course of ascent, the kidneys come into close proximity when they navigate through an arterial fork. One more possible method of occurrence could be in relation to lateral flexion of the trunk or rotation of the caudal embryo, and also, the association of asymmetrical horseshoe kidneys with a number of vertebral anomalies supported this hypothesis. Most recently, animal models implicated the association of notochord and sonic hedgehog signaling.[9]

Surgical intervention

The surgical interventional procedures in cases of horseshoe kidney management have been enlisted as nephrostomy, pyelotomy, nephrectomy, pyeloplasty, heminephrectomy, ureterolysis, division of isthmus, resection of the isthmus, nephropexy, and repair of trauma.[10]

The transperitoneal approach, either by colon mobilization or direct approach via mesentery, was found to be the preferred route. The reasons being that this surgical approach would be more convenient, saves operative time and in fact lead to better visualization of anatomic structures in the purview of operative area, and also it allows to perform bilateral corrective procedures.[11]


  Conclusion Top


Although the occurrence of horseshoe kidney is not very uncommon, the incidence of unilateral chronic pyelonephritis with parenchymatous isthmus has not been reported in literature yet. Furthermore, only in the past few decades, there was some significant surgical progress achieved in its management which can, in fact, improve the patient's wellbeing and prevent life-threatening urologic consequences.

Informed consent

The materials and methods of this study did not require approval by the ethics committee of our institute as it was an incidental finding during routine anatomic dissection of cadavers for teaching and learning for medical students. The cadaver was procured post death and was voluntarily donated by deceased person and his family who also gave informed consent for medical research, and their anonymity is preserved.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the guardian has given consent for her images and other clinical information to be reported in the journal. The guardian understands that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Weizer AZ, Silverstein AD, Auge BK, Delvecchio FC, Raj G, Albala DM, et al. Determining the incidence of horseshoe kidney from radiographic data at a single institution. J Urol 2003;170:1722-6.  Back to cited text no. 1
    
2.
Nahm AM, Ritz E. Horseshoe kidney. Nephrol Dial Transplant 1999;14:2740-1.  Back to cited text no. 2
    
3.
Lippe B, Geffner ME, Dietrich RB, Boechat MI, Kangarloo H. Renal malformations in patients with Turner syndrome: Imaging in 141 patients. Pediatrics 1988;82:852-6.  Back to cited text no. 3
    
4.
Brown JA, Maharaj P, Khan O, Sinanan A. A rare case of emphysematous pyelonephritis within a horseshoe kidney. West Indian Med J 2011;60:229-31.  Back to cited text no. 4
    
5.
Nicholos T. Horse-shoe Kidney. 2020. Available from: https://emedicine.medscape.com/article/441510-overview#a7. [Last accessed on 2021 May 15].  Back to cited text no. 5
    
6.
Krishnan B, Truong LD, Saleh G, Sirbasku DM, Slawin KM. Horseshoe kidney is associated with an increased relative risk of primary renal carcinoid tumor. J Urol 1997;157:2059-66.  Back to cited text no. 6
    
7.
Tom F, Gaillard F. Horse-shoe Kidney. 2020. Available from: https://radiopaedia.org/articles/horseshoe-kidney. [Last accessed on 2021 May 15].  Back to cited text no. 7
    
8.
Doménech-Mateu JM, Gonzalez-Compta X. Horseshoe kidney: A new theory on its embryogenesis based on the study of a 16-mm human embryo. Anat Rec 1988;222:408-17.  Back to cited text no. 8
    
9.
Taghavi K, Kirkpatrick J, Mirjalili SA. The horseshoe kidney: Surgical anatomy and embryology. J Pediatr Urol 2016;12:275-80.  Back to cited text no. 9
    
10.
Glenn JF. Analysis of 51 patients with horseshoe kidney. N Engl J Med 1959;261:684-7.  Back to cited text no. 10
    
11.
Dahlen CP, Schlumberger FC. Surgery of the diseased horseshoe kidney. Am J Surg 1957;93:405-12.  Back to cited text no. 11
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]



 

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