Summary: A 31-year-old man presented with an incidental finding of
microscopic hematuria during a routine check-up. In complementary
work-ups, a high serum BUN and creatinine level were also noted,
and a renal ultrasound was performed. The ultrasound showed
multiple bilateral renal cysts with suspicious bilateral
hydronephrosis. Exact evaluation of the hydronephrosis was
impossible due to the presence of numerous kidney cysts.
Summary: Laboratory findings were:
- normal CBC,
- microscopic hematuria (8-10 RBC/ HPF)
- no pyuria,
- serum BUN = 45
- creatinine = 2.1
- other findings were normal.
Summary: The physical examination was normal but the patient said that he
experienced occasional vague abdominal pains for a few months. He
also stated that his mother had undergone renal transplantation
about 15 years ago and that 4 of his cousins had renal failure and
were under hemodialysis.
Summary: We performed bilateral ureteroscopy to rule-out the obstructive
nephropathy. The left ureter was normal but there was a moderate
stenosis in the right ureter and a double-pigtail ureteral stent
was placed. On performing a kidney-ureter-bladder (KUB) radiograph
to assess the correct position of the stent, we noted an unusual
stent path (Figure 1). We performed an abdominal computed
tomography (CT) scan to rule-out mass lesions that could possibly
displace the right ureter. We were unable to perform an intravenous
pyelogram because of the high creatinine levels. On CT scan, we
found that the kidneys were also in a horseshoe formation (Figure
2) and the diagnosis of polycystic horseshoe kidney was confirmed.
Since the serum creatinine level remained unchanged, the stent was
removed and no hydronephrosis was observed on repeat renal
ultrasound (Figure 3).
Polycystic horseshoe kidney anomaly.
The KUB showed lateral deviation of the JJ stent within the
right ureter (Figure 1). CT kidney images showed fusion of the
lower poles of the kidneys. The JJ stent was also visible in the
right ureter (Figure 2). The ultrasound after stent removal showed
multiple cysts in both kidneys as well as the isthmus. A large cyst
containing a hematoma was visible in the left kidney (Figure
About 1 in 1000 individuals has some type of renal fusion, the
most common being the horseshoe kidney. The incidence of horseshoe
kidney is 1 in 400 to 1 in 800 people, and is more common in boys
than girls.1,2 The two kidneys fuse across the
midline,usually at their lower poles, by renal tissue or a fibrous
band. The horseshoe kidney is usually lower than normal because the
inferior mesenteric artery limits its ascent. It can also be
malrotated and is prone to reflux, obstruction, infection and stone
formation. The autosomal-dominant form of polycystic kidney disease
(ADPKD) is an important cause of renal failure, accounting for 10%
to 15% of patients who receive hemodialysis.4 The
incidence of this anomaly ranges from 1 in 500 to 1 in 1000 cases.
Because of the presence of multiple cysts, the diagnosis of
hydronephrosis on ultrasound may be difficult. It is not uncommon
for urologists to be involved in the care of patients with either
adult polycystic kidney disease or horseshoe kidney disease. It is
rare with incidence ranges of 1 in 134,000 to 1 in 8 million to
have these 2 congenital disorders simultaneously in the same
patient.2,3 Less than 20 cases have been reported in the
Patients with adult polycystic kidney disease, usually develop
renal failure after 40 years of age. Co-occurrence of this disease
with horseshoe anomaly may lower the age of renal failure and
warrant closer follow-up for younger patients.
- Caglar K, Kibar Y,Tahmaz L, et al. Polycystic horseshoe
kidney.Clin Nephrol. 2001;55:487-488.
- Brum FA, Becker M, Uglione A, Da Ros CT. Polycystic horseshoe
kidney. J Urol. 1997;158:22-29.
- Trapp JD, Zukoski CF, Shelley HS, Goldner F Jr. Nephrectomy for
polycystic horseshoe kidney with successful cadaver renal
allograft. South Med J. 1965;58:1370-1371.
- Hildebrandt F. Genetic renal diseases in children. Curr
Opin Pediatr. 1995;7:182-191.