Renal cell carcinoma in a right malrotated kidney.

Abstract

The authors report a case of renal cell carcinoma in a right malrotated (horizontal axis) kidney. The patient was treated by hand-assisted laparoscopic radical nephrectomy. This is the first report of a horizontal axis malrotated kidney with renal cell carcinoma.

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Korean Journal of Urology
Ⓒ The Korean Urological Association, 2011
792
Korean J Urol 2011;52:792-794
www.kjurology.org
http://dx.doi.org/10.4111/kju.2011.52.11.792
Case Report
Renal Cell Carcinoma in a Right Malrotated Kidney
Tae Joon Lim, Seung Kwon Choi, Hyun Wook You, Myung Joon Kim, Jae Sung Ahn, Tae Gu Kim,
Jin Ill Kim, Seung Hyun Jeon
Department of Urology, Kyung Hee University Medical Center, Seoul, Korea
The authors report a case of renal cell carcinoma in a right malrotated (horizontal axis)
kidney. The patient was treated by hand-assisted laparoscopic radical nephrectomy.
This is the first report of a horizontal axis malrotated kidney with renal cell carcinoma.
Key Words: Carcinoma, Renal cell; Malrotation; Nephrectomy
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial
License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use,
distribution, and reproduction in any medium, provided the original work is properly cited.
Article History:
received 5 April, 2011
accepted 4 July, 2011
Corresponding Author:
Seung Hyun Jeon
Department of Urology, Kyung Hee
University Medical Center, 1,
Hoegi-dong, Dongdaemun-gu, Seoul
130-702, Korea
TEL: +82-2-958-8537
FAX: +82-2-959-6048
E-mail: juro@chol.com
Kidney malrotation is found in 1 of 939 autopsies and is fre-
quently observed in patients with Turner’s syndrome.
Most often, kidney malrotation is found in conjunction with
another renal abnormality, such as ectopia or a horseshoe
kidney. In most malrotation cases, the malrotation occurs
ventrally, ventromedially, dorsally, or laterally. As far as
we know, there are no reports of kidney malrotation with
a horizontal axis in conjunction with renal cell carcinoma
(RCC). The authors hereby present a case of RCC in a hori-
zontal axis malrotated kidney that was successfully treat-
ed by hand-assisted laparoscopic radical nephrectomy.
CASE REPORT
A 51-year-old female had palpitations and radiating back
pain and underwent whole-aorta angio 3D computed to-
mography (CT). The CT revealed a horizontal axis right
kidney with a 4.2 cm, lobulating contour multilocular cystic
mass at the lower pole. There were multiple irregular, en-
hancing septations with an enhancing solid portion and
central calcification in the mass. The renal artery was lo-
cated ventrally and the renal vein was located dorsally. The
renal pelvis was located caudal to the renal vessels (Fig. 1).
She was diagnosed as having cystic RCC in the horizontal
axis right kidney and underwent hand-assisted laparo-
scopic radical nephrectomy in September 2010.
Under general anesthesia, the patient was positioned in
the left lateral decubitus position. A 7 cm laparoscopic
hand-assist device was placed in the right lower quadrant
with the placement of two additional 10 mm ports directly
cephalad along the lateral rectus border, allowing 8 cm of
separation between the ports and the hand-assist device.
Following dissection into the retroperitoneal space, the
kidney was separated from the psoas muscle, adjacent bow-
el, and liver. There was a 4 cm cystic mass in the horizontal
axis right kidney (Fig. 2). The ureter was carefully isolated
and divided. The renal artery and renal vein were adhered
together, so we used an Endo-GIA universal stapler
(Covidien Surgical, Dublin, Ireland) and divided them,
thereby isolating the entire right kidney. The specimen
was entrapped in a laparoscopic sac and extracted. The pro-
cedure was completed successfully with a surgical time of
1 hour and an estimated blood loss of 100 ml. Patient-con-
trolled analgesia with morphine was discontinued on post-
operative day one. Postoperatively, the patient did not de-
velop any complications. Pathology revealed the tumor to
be a clear cell carcinoma (Fuhrman grade 3) with the tumor
limited to the kidney (T1a) and with negative resection
margins. In December 2010, follow-on CT revealed no re-
currence of the disease.
DISCUSSION
The adult kidney, as it assumes its final position in the
‘renal’ fossa, orients itself so that the calyces point laterally
and the pelvis faces medially. When this alignment is not

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Korean J Urol 2011;52:792-794
Horizontal Axis Malrotated Kidney with RCC
793
FIG. 1. Computed tomography of a horizontal axis right kidney (A) and of a renal cell carcinoma in the lower pole of the horizontal
axis right kidney (B) and three-dimensional reconstruction of the kidney malrotation (C).
FIG. 2. Operative finding showing 4 cm sized cystic mass in the lower pole of the horizontal axis right kidney (A), gross finding of
specimen (B).
exact, the condition is known as malrotation. Most often,
the inappropriate orientation is found in conjunction with
another renal anomaly, such as ectopia with or without fu-
sion or a horseshoe kidney.
It is thought that medial rotation of the collecting system
occurs simultaneously with renal migration. The kidney
starts to turn during the 6th week, just as it is leaving the
true pelvis, and it completes this process, having rotated
90 degrees toward the midline, by the time ascent is com-
plete at the end of the 9th week of gestation.
It has been postulated that rotation is actually the result
of unequal branching of successive orders of the budding
ureteral tree, with two branches extending ventrally and
one dorsally during each generation or division. Each ure-
teral branch then induces differentiation of the metaneph-
rogenic tissue surrounding it to encase it as a cap. More pa-
renchyma develops ventrally than dorsally, and the pelvis
seems to rotate medially. Weyrauch accepted this theory
of renal rotation to be the result of excessive ventral versus
dorsal branching of the ureteral tree and concluded that the
fault of malrotation lies entirely with the ureter [1]. A
late-appearing ureteral bud may insert into an atypical
portion of the renal blastema, leading to a lessened propen-
sity for the developing nephric tissue to shift. Late appear-
ance of the ureteral bud is almost always associated with
an aberrant origin from the Wolffian duct; This translates
into ureteral ectopia at the level of the lower urinary tract.
The renal blood supply does not appear to be the cause or
a limiting factor in malrotation but rather follows the
course of renal hyporotation, hyper-rotation, or reverse
rotation.
There are two divergent opinions in the anatomical liter-
ature concerning the definite position of the kidneys.
According to the first, the kidney ascends in the retro-
peritoneal space during precocious ontogenetic develop-
ment. The renal rudiment occurs in the pelvic region, at the
level of the L2 to L3 vertebrae, with the dorsal convex bor-
der and the ventral hilum touching the abdominal wall. To
place itself in the definite position, the kidney undergoes
a process of ascension and rotation. Between the 6th and
the 9th week, the kidney ascends to the lumbar region along
the dorsal aorta. The exact mechanism is unknown. An in-

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Korean J Urol 2011;52:792-794
794
Lim et al
ductive substance secreted by the developing kidney may
play a role.
The second opinion states that the kidney undergoes a
pseudoascension caused by the fast development of the
caudal extremity of the fetus [2-4].
In most malrotation cases, malrotation occurs ventrally,
ventromedially, dorsally, or laterally. In our case, however,
the renal pelvis faced the medial side, but the long axis of
the kidney was lying ventral to dorsal. The upper pole and
lower pole of the kidney were indistinctive. Therefore, in
this case, the process of malrotation likely did not follow
the ordinary fashion. It is likely that the kidney rotated
cranially or caudally, not medially or laterally.
The ectopic kidney can be located in the pelvis, in the ab-
domen, or, rarely, in the thorax (0.3%) and can be unilateral
or bilateral. The most frequent cases of renal ectopia de-
scribed in the literature of the field occur in male patients
and are located on the right side of the pelvis [5-7].
Generally, an ectopic kidney is smaller, is of irregular
shape and variable rotation, and is vascularized by multi-
ple arteries with various levels of origin.
In some cases of ectopic kidney, there is often a bizarre
rotation of the kidney as in our case [8-10]. However, the
malrotated kidney was located at a similar level to the con-
tralateral kidney and was also located in the retro-
peritoneal space. The renal vessels were also located at the
L2-3 level. Therefore, it was not an ectopic kidney. The proc-
ess by which this malrotation occurred is not clear, but we
can assume that the malrotation occurred during the as-
cension process or that the axis developed horizontally and
proceeded ascension.
We are the first to report RCC in a malrotated kidney.
Several cases of renal stones in an ectopic kidney or malro-
tated kidney have been reported, but no cases of RCC have
been reported in an abnormal kidney.
The malrotated, ectopic kidney has clinical significance
owing to its atypical location and malrotation. We are the
first to report a horizontal axis kidney located in the retro-
peritoneal space. It is unknown whether the malrotated
kidney is vulnerable to RCC development, but we are the
first to report RCC in a case of kidney malrotation.
Conflicts of Interest
The authors have nothing to disclose.
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