King Edward Memorial Hospital - Departments: Radiology

Radiology

Case of the Month

Case No. :	62
Month :	February
Year :	2004
Contributor :	Dr. Farnaj Sarwat

Other Cases

Radiological Findings

Discussion

CLINICAL PROFILE :

A 45-year-old woman complained of dysuria, lower abdominal pain and increased frequency of micturation. Her clinical examination was unremarkable.

Routine& microscopic examinaition of the urine showed 2-4 pus cells/high power field.

RADIOLOGICAL FINDINGS:

The plain radiograph of the abdomen was unremarkable. The intravenous urogram showed fused ectopic kidneys at the level of L3-L5 vertebrae with a single ureter crossing the midline to the right (Figs. 1,2)


Fig.1	Fig.2

Retrograde pyelography revealed a single ureter passing from the right ureteral orifice to the 'left' kidney crossing the midline at the level of S1 vertebrae. (Fig. 3)

Fig.3

Ultrasonography revealed ectopic kidneys fused at their upper poles. (Fig. 4)

Fig.4

Computed tomography of the abdomen showed the ectopic kidneys to be fused at their upper pole with the pelvis being displaced anteriorly. The ureters joined in midline at the level of L5 vertebrae and crossed the midline to right side of bladder. A mesenteric cyst was incidentally detected on left side.(Figs 5,6,7)


Fig.5	Fig.6

Fig.7

Isotope 99m Tc-DTPA & 99m Tc-DMSA scan showed low lying and anteriorly situated kidneys .The cortical tissue of the kidney were not individually distinguishable (Fig 8)

Fig.8

DISCUSSION:

Low lying horseshoe kidney fused at upper pole and drained by a single ureter crossing the midline is a rare anomaly.

A satisfactory embryological explanation for such an anomaly is not readily available.

It is postulated that a single ureteral bud crosses to the opposite side and then divides into two halves with half crossing the midline before each influenced the development of its renal mass. Another possible explanation is that of failure of one ureter to develop, associated with branching of the other ureteral bud in early fetal life to meet both renal blastemas -one for the right and other for left kidney.

Associated anomalies are congenital scoliosis, vesico-ureteral reflux and complete situs inversus with dextrocardia. Extra-urinary anomalies, however, were not seen in this case.