| Print Date: | May 26, 2013, 7:51 am |
| Title | Partial multicystic dysplastic kidney in a patient with horseshoe kidney |
| Text | The horseshoe kidney consists of fused left and right lower renal poles. Abnormal renal orientation (medial lie of the lower poles) and demonstration of a predominantly hypoechoic band of tissue extending across the midline on sonography suggests the diagnosis of horseshoe kidney. The band of connecting tissue – composed either of a fibrous band or actual renal parenchyma -- is typically seen anterior to the aorta at the level of the 4th lumbar vertebral body. In adults, a horseshoe kidney may be mistaken for a retroperitoneal mass. Indeed, a horseshoe kidney may be erroneously identified as a thrombosed left renal vein crossing the aorta, for retroperitoneal fibrosis, or for lymphadenopathy or lymphoma. Rarely, aortic aneurysms coexist with a horseshoe kidney. On ultrasound, care should be taken to recognize an abnormal renal axis (i.e., avoid alignment of the transducer along the renal axis without realizing that the axis is, in fact, abnormal), and a careful search for the connecting band of tissue should be performed, as some connections are quite thin and, therefore, easily missed (1).
Multicystic dysplastic kidney (MCDK) disease is a common cause of palpable abdominal mass in the newborn. MCDK is unilateral, and is associated with an increased incidence of renal anomalies such as ureteropelvic junction obstruction of the contralateral kidney or, as in this case, other anomalies such as horseshoe kidney. As its name implies, the sonographic appearance of MCDK is that of a multiloculated cystic mass which results in replacement of the normal renal parenchyma and lobulation of the renal outline. The cysts do not connect to the renal pelvis as in the case of hydronephrosis (1). |
| References: | 1. Rumack CM, Wilson SR, and Charboneau JW. Diagnostic Ultrasound. Mosby-Year Book: St. Louis; 1991, pp. 230, 305, 343-344, 1184-1185, 1188-1189. |
| Contributor | Jason Rexroad (Civilian Medical Center) |
| Peer Reviewer | Perry J. Pickhardt, M.D. (National Capital Consortium) |
| Record Number | : 4314 |
| Created | 2002-11-13 06:50:26-05 |
| Modified | 2004-06-09 22:54:28-04 |
| Category: | Anatomy, Normal and Measurements |
| Location: | Genitourinary |
| Sublocation: | Kidney |
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