This is “Advance Publication Article” Kurume Medical Journal, 66, 55-58, 2019 Case Report Case Report of a Pelvic Crossed Fused Renal Ectopic Kidney EMILY SIMONDS*, JOE IWANAGA**, †, ‡, SHOGO KIKUTA‡, MAIA SCHUMACHER*, GRAHAM DUPONT*, JUAN ALTAFULLA*, §§, ##, EMRE YILMAZ*, #, ##, ROD J. OSKOUIAN* , ## AND R. SHANE TUBBS**, § * Seattle Science Foundation, Seattle 98122, ** Department of Neurosurgery, Tulane Center for Clinical Neurosciences, Tulane University School of Medicine, New Orleans 70112, USA, † Division of Gross and Clinical Anatomy, Department of Anatomy, ‡ Dental and Oral Medical Center, Kurume University School of Medicine, Kurume 830-0011, Japan, § Department of Anatomical Sciences, St. George’s University, St. George’s, Grenada, §§ Department of Neurosurgery, Hospital Santo Tomas, Panama City, Panama, # Department of Trauma Surgery, BG University Hospital Bergmannsheil, Ruhr University Bochum, Bochum 44789, Germany, ## Swedish Neuroscience Institute, Swedish Medical Center, Seattle 98122, USA Received 3 July 2018, accepted 7 January 2019 J-STAGE advance publication 24 April 2020 Edited by KEI FUKAMI Summary: Herein we present a case of a horseshoe kidney with crossed fused renal ectopia. Both of these pathologies are congenital anomalies; however, to date, there are few cases that present with both. In this case, dis- covered during routine dissection, the fused kidney was mostly left-sided and very low in the pelvis. No renal artery arose from the right wall of the abdominal aorta, and the right renal vein drained into the lower part of the inferior vena cava (IVC) where the right and left common iliac veins joined. It is essential for clinicians and sur- geons to understand these types of congenital anomalies, as they could impact patient care. Key words Ectopic kidney, inferior vena cava, horseshoe kidney, cross fused renal ectopia, renal artery, cadaver, anatomy INTRODUCTION better understand possible complications of the sur- A horseshoe kidney (HSK) is the most common con- geries in the region they are located. genital kidney anomaly with an incidence of 1 in 500 [1]. An HSK is a subtype of the fused kidney, e.g., L- CASE REPORT shaped kidney, sigmoid kidney, or pancake kidney. These kidney anomalies show fusion between the During routine dissection of the abdominal cavity, right and left kidneys. Crossed fused renal ectopia an artery was found arising from the right common (CFRE) is a congenital ectopia of one kidney to the iliac artery in a male, Caucasian fresh-frozen cadaver contralateral side with fusion to the kidney on the whose age at death was 85 years. The artery was traced same side. The origin and course of the renal vessels distally and found to be the renal artery, which trave- are variable depending on the shape and size of the led to a kidney displaced in the pelvis. Further dissec- CFRE as well as the HSK. Knowledge of the renal tion of this kidney revealed that this was the right side vessels surrounding the kidney anomalies helps us to of the fused kidney. This fused kidney was slightly Corresponding Author: Shogo Kikuta, DDS, PhD, Dental and Oral Medical Center, Kurume University School of Medicine, 67 Ashahi-machi, Kurume, Fukuoka 830-0011, Japan. Tel: +81-942-31-7577, E-mail: [email protected] Abbreviations: CFRE; Crossed Fused Renal Ectopia, HSK; Horseshoe Kidney, IVC; Inferior Vena Cava. 56 SIMONDS ET AL. curved with deviation to the left side, which is defined tween the third lumbar vertebra and upper part of the as CFRE (Figure 1). The CFRE was positioned be- sacrum level so that the right kidney was in the pelvis. The CFRE was then resected from the abdominal cav- ity with related structures to be fixed in the formalin (Figure 2). The right kidney was located in the midline and anterior to the right and left common iliac arteries. Both hila faced anteriorly, and the left renal pelvis was slightly enlarged. The right renal hilum received two right renal arteries, which arose from the anterior as- pect of the abdominal aorta 15mm inferior to the infe- rior mesenteric artery and the anterior wall of the right common iliac artery, respectively. The left renal hilum was supplied by only one renal artery that arose from the lateral wall of the abdominal aorta. No renal artery was branched off the right wall of the abdominal aorta. Two renal veins drained from the right renal hilum. The one drained into the lower part of the IVC where the right and left common iliac veins joined and the other drained into the left wall of the IVC 25 mm infe- rior to the left renal vein. The left renal vein received Fig. 1. Ex vivo image of the pelvic crossed fused the left testicular vein, ran in front of the abdominal renal ectopic kidney reported herein. AA, abdominal aorta; CIA, common iliac artery; aorta below the superior mesenteric artery and drained IMA, inferior mesenteric artery; IVC, inferior vena into the inferior vena cava (IVC). No renal vein cava; RA, renal artery; RV, renal vein; TV, testicular drained into the right wall of the IVC. vein; U, ureter. Fig. 2. Anterior view of the embalmed crossed fused renal ectopia and adjacent struc- tures with formalin. before (a) and after (b) the abdominal aorta and arteries retracted to the left. AA, abdominal aorta; CIA, common iliac artery; CIV, common iliac vein; IMA, inferior mesenteric artery; IVC, inferior vena cava; RA, renal artery; RV, renal vein; SMA, supe- rior mesenteric artery; TA, testicular artery; TV, testicular vein; U, ureter. Kurume Medical Journal Vol. 66, No. 1 2019 CROSSED FUSED RENAL ECTOPIA 57 DISCUSSION Malek et al. showed that 90% of pediatric patients CFRE is a relatively uncommon congenital kidney with CFRE are highly likely to have other anomalies anomaly with an incidence at autopsy of 1 in 2000 in organ systems outside of the genitourinary system [1,2]. According to Liu et al., CFRE occurs up to two (18/20 patients) [9]. However, in adults anomalies times more often in men than in women, and more outside of the genitourinary system were approxi- often on the right side [3]. In the present case, the mately 23% [10]. fused kidney was mostly located on the left side, and Most case reports of CFRE were found inciden- the right kidney was on the midline. To our knowledge tally. Treatment is only indicated when symptoms in this is a unique finding. Also, no renal artery arose the upper urinary tract are significant—most frequent- from the right wall of the abdominal aorta, which is ly these include nephrolithiasis and vesicoureteral re- why we diagnosed this kidney as CFRE. CFRE is the flux [11]. If an ectopic kidney is found to be non- second most common fusion anomaly of the kidney. functioning, then surgical excision may be necessary There are six unique types of CFRE that have been [12]. Surgery may also be necessary due to the poten- identified to date: inferior crossed fused ectopia, sig- tial of an entrapped ureter, for which the kidney’s isth- moid or S-shaped kidney, lump kidney, disc kidney, mus requires division [12]. In cases that require surgi- L-shaped kidney, and superior crossed fused ectopia cal management, ureteric reimplantation can be [3]. The present case was the inferior crossed fused performed using the cross trigonal Cohen’s technique ectopia. Surgeons should be aware of this type of kid- [12]. However, to date, there are no specific guidelines ney anomaly as it may affect the position and course for the management of CFRE. It is important for clini- of the ureter, renal vessels, and kidneys themselves cians to know that the fused kidneys do not need to be [4,5]. These anomalies can be diagnosed using com- separated unless symptoms are present [11]. CFRE puted tomography and magnetic resonance images, can occasionally be palpated as abnormal abdominal but may also could be overlooked if knowledge of masses [7]. Surgical procedures for kidney anomaly variants is lacking. Patients presenting with CFRE are such as CFRE may lead to complications because of often asymptomatic, but they sometimes report the the complex vascular system [2]. Additionally, there following varied symptoms: flank pain, urolithiasis, have been case reports where complete nephrectomy abdominal pain, blood in the urine, no creation of led to surgical complications [9]. urine, frequent urinary tract infections, renal failure, fever, hydronephrosis, and high blood pressure [3]. CONCLUSION Also, a CFRE could be misdiagnosed as an abdominal mass [6]. An HSK with a CFRE is a rare anomaly, which Embryologically, the kidney begins developing in can be clinically significant. As clinicians, it is essen- the pelvis during the fourth week of gestation, fol- tial to understand variations of the kidneys and their lowed by ascension at week seven—with internal ro- symptomologies [13-18]. Additionally, such varia- tation over the iliac crest—and at week nine it obtains tions may be relevant to surgeons when planning lat- its final position [7]. In patients with CFRE, there is a eral surgeries such as the extreme lateral interbody fu- lack of fusion and lack of complete rotation. It is im- sion of the lumbar spine due to variations in the portant to note that CFRE may lead to fistula forma- vasculature of a CFRE. Appropriate sonography and tion between the collecting ducts and the lymphatics comprehensive imaging should be completed on pa- and can present as milky-colored urine [3]. tients who have CFRE anomalies to determine if any The blood supply to the kidneys appears to be ab- interventions or modifications of surgical procedures normal in all known case reports. Of the 22 case re- need to take place. ports that Hertz reviewed in 1977, each had a unique blood supply, and no consistent arterial pattern could ACKNOWLEDGMENT: The authors wish to thank the indi- be discerned [8].