¹ SONOSCAN, Ultrasonic Scan Centre,  16B, Venkatachalam Road,  R.S.Puram, Coimbatore. Pin: 641002  India.
² Consultant,  Department of Obstetrics and Gynecology, and ³  Pediatric Surgeon, GKNM Hospital,  Coimbatore.

Synonym: None

Prevalence  Not known - In one report of 48 children with multicystic kidney, there was one case with horse shoe kidney with unilateral multicystic dysplasia.

Case report:

A 34-year-old primigravida was referred for sonography in her 26th week of pregnancy to rule out fetal anomalies. Fetal biometry corresponded to 26 weeks. The following image of the renal area were obtained.

An axial scan at the level of the lower pole of the kidney demonstrate cysts of multicystic dysplastic left kidney (MCK) and lower pole of right kidney (RK) scan showing elongated and flattened right adrenal (ADR) because of low placed right kidney (RK). MCK- multicystic dysplastic left kidney.

A coronal scan at a lower level showed cysts of multicystic dysplastic left kidney crossing the midline anterior to the aorta (A) and inferior vena cava (I). (A&I = aorta and inferior vena cava) and extending up to lower pole of right kidney.  These features are diagnostic of horseshoe kidney with unilateral multicystic dysplasia on left side.

The axial  scan of fetal abdomen showing the multicystic dysplastic left kidney. The right kidney is not visualized because it is low placed.

A sagittal scan of multicystic dysplastic left kidney.

The child was delivered normally at term. Postnatal scan was done at 4 months of age, which confirmed the prenatal diagnosis.

Post natal axial scan showing the multicystic dysplastic left kidney (MCK) and lower pole of the right kidney (RK) in midline anterior to the aorta (A) and inferior vena cava (I).

Etiology: horse shoe kidney is a result of fusion of upper or lower poles before the ascent of kidneys. Horse Shoe Kidney is low placed because inferior mesenteric artery prevents the isthmus
to ascend up. Multicystic kidney dysplasia is a result of ureteric obstruction in early fetal life.

Associated anomalies: Not known.

Prognosis: depends on associated anomalies. Isolated multicystic kidney carries good prognosis.

Recurrence risk: Sporadic.

Management: Does not alter obstetric management.

References:
1.Krull F, Hoyer PF, Habenicht R, Krohn HP, Offner G, Ehrich JH, Brodehl J. Multicystic kidney dysplasia. Monatsschr Kinderheilkd 1990 Apr; 138(4): 202-5

2. Van Every MJ. In utero detection of horseshoe kidney with unilateral multicystic dysplasia. Urology 1992 Nov; 40(5): 435-7.

3 Borer JG, Glassberg KI, Kassner EG, Schulsinger DA, Mooppan UM. Unilateral multicystic dysplasia in 1 component of a horseshoe kidney: case reports and review of the literature. J Urol. 1994 Nov;152(5 Pt 1):1568-71.