The Comparison of the Incidence of Horseshoe Kidney in Autopsy Cases Versus Urologic Patient Population

Okajimas Folia Anat. Jpn., 76(2-3): 137-140. August, 1999

Halil BASAR, Ruhgun BASAR, M. Murat BASAR and Mine ERBIL

Assistant Professor in Department of Urology, Faculty of Medicine, Kirikkale University, Kirikkale, Turkey Associate Professor in Department of Anatomy, Faculty of Medicine, Hacettepe University, Ankara, Turkey Urologist in Ankara Numune Hospital, 1st Urology Clinic, Ankara, Turkey Assistant Professor in Department of Anatomy , Faculty of Medicine, Hacettepe University, Ankara, Turkey

-Received for Publication, February 15, 1999-

Key Words: Horseshoe kidney, Urology, Anatomy, Autopsy

Summary: This study was applied on 9665 cases between January 1993 and October 1998. Of these, 6985 (72.3%) were urologic patients and 2680 (27.7%) were autopsy cases. The patients having urinary complaint investigated by urine analysis and kidney-ureter-bladder film (KUB), routinely. In all patients who have pathological urine, ultrasonography exam was done and in all patients who established an abnormality on ultrasonografy, intravenous pyelography (IVP) was taken, also. We established the horseshoe kidney in 23 of patients (1/304) and in 6 of autopsy cases (1/447) with overall incidence 1/333. There were 21 male and 8 female with horseshoe kidney (male/female = 2.6/1). Abdominal discomfort with lower lumbar pain and Rovsing's sign were seen in 56.5% and in 65.2% of patients respectively. We concluded that horseshoe kidney incidence is almost the same as reported in the literature, although its clinical appearance is higher in our urologic patient population. In the urological out-patient evaluation, at least Rovsing's sign should be applied to all patients with lower lumbar pain with vague abdominal discomfort and an abdominal ultra- sonographic exam should be applied, if this sign is positive.

The horseshoe kidney is the most common con- Materials and Methods genital fusion anomaly of the kidney. The incidence is 1/400 to 1/1800 in general population, and it is 2 This study was applied on 9665 cases between or 3 times as frequent in men as in women1-3). The January 1993 and October 1998. 6985 of them kidneys generally fuse from the inferior pole by a (72.3%) were urologic patients having urinary paranchimatous or a fibrous band, called isthmus4). complaint investigated by urine analysis and In general, kidneys have an anomaly of rotation kidney-ureter-bladder film (KUB), routinely. In all and position. Ureters arise from the anterior sur- patients who have pathological urine, ultrasonog- face of the kidney, and while descending cross the raphy exam was done and in all patients who isthmus. The fused kidney is especially vulnerable established an abnormality on ultrasonografy, in- to infection, hydronephrosis, calculus formation, travenous pyelography (IVP) was taken routinely, and trauma because of its abnormal position, vas- also. 2680 of them (27.7%) were the autopsy cases cular supply, and pelvicaliceal drainage). autopsied in the Ankara Judicial Medicine Depart- In this study, we have intended to establish the ment. The cases were evaluated according to the incidence and clinical presentation of the horseshoe age, sex, the incidence of the symptoms, uretero- kidney in urologic patient population and in au- pelvic obstruction, stone formation, hydronephrosis topsy cases. and the structure of the isthmus. In the autopsy groups, horseshoe kidney were diagnosed by the anatomic inspection only. The incidence of this entity between the patients

For correspondance please adress to: Halil Basar, M.D., Kirikkale University, Faculty of Medicine, Department of Urology, 71100, Kirikkale, Turkey.

137 138 H. Basar et al.

Table 1. Distribution of the patients and autopsy cases according to age and sex

and the autopsy cases were compared. Table 2. The distribution of the clinical presentation

Results

We established a horseshoe kidney in 29 of 9665 cases (1/333); in 23 of 6985 patients (1/304) and in 6 of 2680 autopsied cases (1/447). Twenty one of them (72.4%) were male and the rest (27.6%) were female. The ratio of the male/female was 2.6/1, and the age range was generally between 20 and 39 (Table 1). There were vague abdominal discomfort with lower lumbar pain in 13 (56.5%) and Rovsing's sign in 15 of 23 patients with horseshoe kidney in clinical presentation (65.2%). Urinary tract infection has been observed in 8 of patients (34.8%) with vesicoureteral reflux (VUR) in 3. Ureteropelvic junction obstruction in 6 (26.1%), adenoma in during the 4-8th weeks of the gestation. The kid- one (4.3%) and renal stone have been noted in neys can not rotate into the inside and ascend from 9 (39.1%) of the cases. One case was a stabbed the pelvis to upper abdomen2). the renal fusion patient who was inspected for the hematuria and defect is occasionally on the superior pole). The decreased hemotacrit level. The retroperitoneal ureters descend while crossing the convex face of hematoma and the horseshoe kidney were de- the isthmus. So, in most of the cases, at the level scribed at the computerized tomography (CT) of of isthmus the ureters are exposed to the pressure; this patient. There was no symptoms in 6 patient 15-30% of the cases are associated with ureter- (26.1%), incidentally was found during the ultra- opelvic obstruction and/or VUR"). Hence, the sonographic exam (Table 2). risk of the stone production, hydronephrosis and The isthmuses were at the inferior pole in both urinary infection of the horseshoe kidney is clinical and autopsy cases, and were like a fibrous high9-11). The incidence of these complications in band in 6 of the cases (20.7%) and a thick para- our study was well adjusted with the literature' 2'13). nchimataus isthmus in the rest (79.3%). Totally, 9 The diagnosis of the horseshoe kidney was asymp- patients (39.1%) were treated surgically and isth- tomatic in 1/3 of the cases newly diagnosed and in mectomy was done during the operations in 4 of 60% of the follow up patients in large series14-16). them. The ratio of the asymptomatic cases was 26.1 % according to our study. In the literature, the incidence of the horseshoe Discussion kidney was 1/400- 1/1800 and 2-3 times at men"). In this study, the incidence was 1/447 in autopsy The horseshoe kidney is a congenital anomaly cases, while 1/304 in urologic patient population. occurring by fusion of the renal blastema at midline This high difference may be due to the only patients Comparison of the Incidence 139 we included in this study were the urologic patient upper urinary tract. Campell's Urology, 6th. ed. Philadel- population. The ratio of male/female was 2.6/1. phia, 1992; vol: 2: 34, pp: 1376-1381. 3) Blackard CE and Mellinger GT. Canser in a horseshoe In the literature, it's described that the horse- kidney: A report of two cases. Arch Surg 1968; 97:616. shoe kidney can be seen in all age groups from fetal 4) Botta GC, Capocasale E and Mazzoni MP. Transplantation life to 80 ages, but in the autopsy series it is mostly of horseshoe kidneys: a report of four cases. Brit J Urol seen in childhood15'17'18). In our study, we observed 1996; 78:181. it especially at 20-39 ages (48.2%) in both. The tu- 5) Brandina L, Mocelin AJ, Fraga AMA and Lacerda G. mor developing ratio in the horseshoe kidney didn't Transplantation of a horseshoe kidney. Brit J Urol 1978; 50:284. show difference when compared to the normal 6) Buntley D. Malignancy with associated with horseshoe kidney, in the literature3'19'20).But the incidence kidney. Urology 1976; 8:146. of hipernephroma (more than 50%), Wilms tumor 7) Das S and Amar AD. Ureteropelvic junction anomalies associated renal anomalies. J Urol 1984; 131:872 (42%) and transitional cell carcinoma was in- 8) Evans WP and Resnick MI. Horseshoe kidney and ur- creased14'15'21).In our study group of 29 cases we olithiasis. J Urol 1981; 125:620. could find only one adenoma (3.4%). The kidney 9) Glenn JF. Analysis of 51 patients with horseshoe kidney. exposed to trauma easily because of the localization New Eng J Med 261; 684:1959 of the horseshoe kidney and the isthmus. As a 10) Hammadeh MY, Calder Cl and Corkery JJ. Pediatric xan- matter of fact, a mass of hematoma formed by thogranulomatous pyelonephritis in a horseshoe kidney. stabbing in one of our cases. Brit J Urol 1994; 73:721. 11) Hohenfellner M, Schultz-lampel D, Lampel A, Steinbach F, In conclusion, horseshoe kidney incidence is al- Cramer BM and Thuroff JW. 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