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Journal of the Anatomical Society of India

Ectopic Kidney and associated anomalies: A Case Report

Author(s): Belsare S.M; Chimmalgi M., Vaidya S.A. & Sant S.M.

Vol. 51, No. 2 (2002-07 - 2002-12)

Department of Anatomy, B.J. Medical College, Pune, India.

Abstract

A case of ectopic kidney of left side was found during routine dissection in the department of Anatomy. It was associated with multiple visceral and vascular variations. Visceral variations were in the form of mechanical displacement of sigmoid colon and mesocolon to the right side, compensatory hypertrophy of the right kidney, consequential absence of renal impression on the spleen, enlarged uterus and displaced ovary. Thus it involved multiple systems. Vascular variations included multiple renal vessels on both the sides, variations in abdominal aorta and inferior venacava, variations in the gonadal vessels, etc. An attempt has been made to systematically document these variation and give possible explanations for the same on the basis of ontogeny.

Although the ectopic kidneys are often nonfunctional, cases of lithiasis or formation of renosigmoid fistulae have been reported in relation to pelvic kidney. In such cases nephrectomy forms the choice of treatment, an effort to save the kidney being made only if the kidney is found to be functioning normally.

Key words: Ectopic Kidney, inferior venacava (IVC), subcardinal vein, renosigmoid fistulae, lithiasis, inferior phrenic arteries, aortic bifurcation

Introduction:

Urinary tract anomalies form a long and exhaustive list. Congential anomalies of urinary tract are often the underlying causes of pathologies. According to Guiterrez, 40% of pathologic conditions of the urinary system are due to these variations. Variations may be in the number, position, shape and size or in rotation of kidney(s), calyces, ureter(s) or bladder. Usually these anomalies are associated with anomaleis of vertebral column, lower gastrointestinal tract, genital tract or spinal cord and meninges.

Ectopic kidney has a reported frequency of 1:500 to 1:110; ectopic thoracic kidney 1:13,000; solitary kidney 1:1,000; solitary pelvic kidney 1:22,000; one normal and one pelvic kidney 1:3,000; and crossed renal ectopia 1:7,000 (Bergman et al). We are reporting a case of ectopic kidney with associated anomalies found during the routine dissection in the department of Anatomy.

Observations:

A case of unilateral ectopic kidney was found during routine dissection in a female cadaver of Indian origin (fig. 1). Right kidney was normal in position. Left kidney was situated anterior to the bodies of L5, S1 and S2 vertebrae. It was oval in shape and measured 14 cm vertically, 10 cm transversely and 4.5 cm in its thickness. Its dorsal surface was smooth; ventral surface was marked with hilum and was lobulated. Long axis of the left kidney was passing downwards, forwards and to the left.

Upper pole of the kidney was close to the midline, related to the left common iliac vessels superiorly. Lower pole, situated in the true pelvis was tilted to the left approaching the left lateral pelvic wall. Right margin was related to sigmoid mesocolon and colon, which were pushed to the right ilac fossa. Left margin was related to left common iliac vessels, left internal iliac vessels and left ovarian vessels from above downwards. Dorsal surface was related to bodies of 5th lumbar, 1st and 2nd sacral vertebrae. Ventral surface was related largely to the coils of intestines and in its lower part to the uterus and to the left ovary.

Ventral surface was characteristically marked by a large hilum, occupied by the renal pelvis. The ureter coursed around the body of uterus and crossing over the uterine artery it opened into the urinary bladder. From the right superior quadrant of the hilum, main renal vein emerged; ascending in front of the kidney and right common ilac vessels, it drained into ventral aspect of inferior vena cava.

A pair of renal vessels emerged from left upper quadrant of the hilum. Artery was a ventral branch of the abdominal aorta arising 1 cm proximal to the aortic bifurcation. Accompanying vein was a tributary of left common iliac vein. Close to the lower pole, another set of renal vessels emerged from the ventral surface (not seen in the picture) and these were branch/tributary of internal iliac vessels.

Other associated anomalies seen were:

  1. Enlarged right kidney with two renal veins both draining into IVC and two renal arteries. The renal arteries were lateral branches of abdominal aorta, one was retrocaval and another was passing in front of IVC.
  2. Sigmoid colon and mesocolon was shifted to the right side.
  3. Uterus was enlarged to 12-14 weeks' size and was firm in consistency. On section, it showed caseation.
  4. Left ovary was in recto-uterine or rather nephro-uterine pouch.
  5. Left overian vessels drained into left common iliac vessels.
  6. Right ovarian vein drained into lower right renal vein.
  7. Left suprarenal vein drained into IVC directly.
  8. Inferior phrenic arteries were arising by a common trunk as the first ventral branch of abdominal aorta.
  9. As a consequence of ectopic kidney, spleen showed no renal impression.

Discussion:

Cases of ectopic kidney, unilateral or bilateral have been reported in the literature regularly (Moore & Parsaud, 1999; Hollinshead, 1971; Benjamin & Tobin, 1951; Baurys, 1951; Gray and Skandalakis 1972 etc.) Incidence of ectopic kidney reported in literature is 1:500 to 1:110. Incidence of one normal and one pelvic kidney is 1:800 to 1:3000 (Gray and Skadalakis 1972). In our case the kidney was not entirely pelvic, its upper pole being at the level of L5. This position is due to halt in its ascent during the development. It was interesting to note a series of other anomalies associated with it. As a consequence to left kidney being ectopic, spleen did not show the renal impression. Sigmoid colon along with mesocolon was pushed to the right side as the ectopic kidney occupied its normal site. For the same reason, ovary was found in the recto uterine (nephrouterine) pouch. Possibly because of ectopic kidney being nonfunctional or less functional, right kidney was enlarged as a compensatory mechanism. In addition to these, uterus was enlarged to 12 to 14 weeks' size and this variation seems to have no relation to the existence of ectopic kidney. Left ureter was crossing over the uterine artery instead of passing under it.

In ectopia, the vascularization pattern remains 'frozen' at whatever development stage the ascent ceases (Gray & Skandalakis 1972). Un-ascended kidney seen by us showed multiple vessels - two arteries and three veins. It is to be expected because the ascending kidney receives blood supply from neighbouring vessels. In this case, as the ascent of left kidney has been arrested at the level of junction between the common iliacs with aorta/ inferior venacava, it is being supplied by these vessels. In order to accommodate the changes in blood supply to the ectopic kidney, both abdominal aorta and IVC showed certain variations.

Abdominal aorta had five ventral branches. In addition to the normal three branches it had the common trunk of inferior phrenics as its first ventral branch. Left renal artery was the last ventral branch given just before aortic bifurcation. It was interesting to note that even though right renal arteries (two) were lateral branches, left renal was a ventral branch. Left gonadal artery was arising from left common iliac instead of from aorta. Three veins drained left kidney. The main vein drained into IVC on its ventral aspect; the vein accompanying the main renal artery drained into left common iliacs and the vein emerging from the lower pole drained into the left internal iliac vein. Hence, IVC received left renal vein as its first tributary on its ventral aspect. Other changes seen in IVC were the left suprarenal vein draining into it directly. In this case, the left suprarenal vein must have developed from incorporating a segment of left subcardinal vein and the intersubcardinal anastomosis, which would be part of left renal vein in the normal course.

Gonadal veins also deviated from the normal on both the sides; the right drained into the lower right renal vein and the left drained into left common iliac vein. In the early fetal life the lower renal vein must have drained into the right subcardinal vein. Subsequently this part of the subcardinal may have been incorporated into the right lower renal vein.

The gonadal vein developing from the caudal part of the subcardinals therefore must have formed the tributary of the right lower renal vein. The left side gonadal vessels were branch/tributary of left common iliac vessels. Ascent of kidney preceedes descent of gonads, which reach pelvic brim by 28th week of intra-uterine life. The left kidney at the pelvic brim must have allowed formation of multiple vascular channels at that level. When the ovary descended to this level these channels must have established secondary communications with the ovarian vessels. Subsequently, these communications must have persisted as definitive ovarian vessels - thus explaining their drainage into common iliacs and the original vessels from aorta and IVC must have disappeared.

Unilateral ectopic kidney is commoner than bilateral. It is also found that congenital pelvic kidney is commoner on left side than on the right. In our case, the ectopia was unilateral and on the left side in accordance with the findings of others. The frequency is quoted to be higher in males than in females. In our case it was found in a female cadaver.

Kidneys in ectopic (pelvic) position are dysplastic and often non-functional. They may go undetected in life and get noticed only after death either in autopsy or during dissection. Often they are diagnosed for presence of a pelvic mass or on pyelogram. Ectopic or congenital unascended kidney has to be carefully differentiated from (acquired) nephroptosis where the length of the ureter is normal. Symptoms due to ectopic kidney may vary from none to pain; hydronephrosis, pyelonephritis, renosigmoid fistulae or lithiasis (Gray and Skandalasi 1972). In case of females, the pelvic kidney may result in obstetric complications (Banner 1965).

Treatment is mainly based on the functional capacity of the kidney; nephrectomy being done on non-functional kidneys and corrective procedures forming the mainline of treatment for the functional kidneys.

References:

  1. Banner E.A. (1965): The ectopic kidney in obstetrics and gynaecology. Surgery, Gynaecology and Obstetrics. 121: 32 36.
  2. Baurys W. (1951): Fused pelvic kidneys. Journal of Urology. 65: 781-783.
  3. Benjamin J.A. and Tobin C.E. (1951): Abnormalities of kidneys, ureters and perinephric fascia - Anatomic and clinical study Journal of Urology. 65: 715-733.
  4. Bergman R.A., Afifi A.K. and Miyauchi R In: Illustrated Encyclopedia of human anatomic variation. opus IV: Organ system: Urinary system: Kidneys, ureters, bladders and urethra @ www/virtual hospital.com.
  5. Gray S.E. and Skandalakis J.E. Embryology for surgeons The embryological basis for the treatment of congenital defects. W.B. Saudners Co. Philadelphia. London. Toronto pp. 472-474 (1972).
  6. Hollinshead H.W. Anatomy for surgeons - The thorax, abdomen, and pelvis. In: Kidneys, ureters and suprarenal glands. 2nd Edn; Vol II. Harper and Row Publishers, Newyork. Evanston. San-fransisco. London. pp 548-550 (1971).
  7. Moore, K.L. and Persaud T.V.N. The developing human Clinically oriented embrylogy. In: Urological system 6th Edn; W.B. Saunders Co. Philadelphia pp 312 (1999).

Missing Image

Fig. 1 Photograph of a dissected specimen showing:

  1. Left kidney
  2. Left main renal v.
  3. Left renal a.
  4. IVC
  5. Aorta
  6. Right kidney
  7. uterus
  8. left ovary
  9. left ovarian vessels
  10. right ovarian vessels
  11. left pelvis and ureter
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