Multicystic Dysplastic Kidney - Children's Hospital Boston

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My Child Has:

Multicystic Dysplastic Kidney

Programs that treat this condition

General Renal Consultation Program

What is multicystic dysplastic kidney?

A multicystic dysplastic kidney is the result of abnormal fetal development of the kidney. The kidney is replaced by multiple cysts which vary in size. There is little or no normal function to this kidney. Historically, it was one of the most common causes of abdominal mass as discovered by physical examination. Currently with the use of prenatal ultrasound, most of these are discovered prior to birth. The incidence is approximately 1 in 4300 live births.

The vast majority of multicystic kidneys occur on one side (left side). Occasionally it may occur on both sides but this is incompatible with life, primarily because the kidney is responsible for producing the amniotic fluid which is vital to lung development. In most cases this condition isn't cause for alarm, since one properly functioning kidney is sufficient to provide the normal amount of amniotic fluid. The incidence between males and females is approximately equal. This condition is most common in the Caucasian population.

How is multicystic dysplastic kidney diagnosed?

It is important to have your child evaluated by a pediatric urologist after birth since the normal kidney can have other associated conditions such as vesico-ureteral reflux, uretero-pelvic junction obstruction, or uretero-vesical junction obstruction. The risk of an associated abnormality is as high as 51 percent. These are all surgically correctable problems and in some cases may resolve with observation alone. The best course for your child will depend on the results of his/her radiologic studies and your pediatric urologist's recommendation. Radiologic evaluation can include a postnatal (after birth) ultrasound along with:

voiding cystourethrogram (VCUG) - a specific x-ray that examines the urinary tract. A catheter (hollow tube) is placed in the urethra (tube that drains urine from the bladder to the outside of the body) and the bladder is filled with a liquid dye. X-ray images will be taken as the bladder fills and empties. The images will show if there is any reverse flow of urine into the ureters and kidneys.
renal ultrasound (RUS)- a non-invasive test in which a transducer is passed over the kidney producing sound waves which bounce off the kidney, transmitting a picture of the organ on a video screen. The test is used to determine the size and shape of the kidney, and to detect a mass, kidney stone, cyst, or other obstruction or abnormalities.
intravenous polygram (IVP) - a special x-ray of the kidneys, ureters and bladder that involves injection of a contrast agent that fills the urinary tract tract on the x-ray and helps the doctor to see the organs. The IVP shows how well the kidneys drain urine.

Each child is unique and your child's pediatric urologist will determine which of the tests above are most appropriate.

How is multicystic dysplastic kidney treated?

There is no uniform consensus on the best form of treatment for this condition. Historically, these were all removed by nephrectomy (removal of the diseased kidney) since these children presented with a large abdominal mass and the precise diagnosis was difficult to determine. With the advances in medical imaging, the correct diagnosis can be established with near certainty which has led some clinicians to recommend surveillance instead of nephrectomy.

Many of these kidneys will slowly regress. The natural history of this condition is being monitored by a national registry (National Multicystic Kidney Registry). The risk of developing a malignancy within a multicystic dysplastic kidney is low. Since 1957 there have only been nine reported cases. The development of hypertension (high blood pressure) is also low, with only four patients of 508 within the Registry developing hypertension. Currently, most pediatric urologists recommending surveillance will obtain serial ultrasound examinations until the kidney totally regresses or becomes undetectable by ultrasound. However, surgical removal still remains a viable option. In these young children, the kidney may be removed through a small skin incision or by laparoscopic surgery.

Laparoscopic Nephrectomy

Laparoscopic nephrectomy can be performed from the front (transperitoneal) or from the back or side (retroperitoneal). Most kidneys can be removed using the retroperitoneal approach, which seems to permit even more rapid recovery. If the ureter (the tube connecting the kidney with the bladder) needs to also be removed, the transperitoneal approach is sometimes better.

When the kidney is to be removed laparoscopically, it is performed under general anesthesia and three or four punctures are used. The kidney is removed through one of the puncture sites, sometimes using a small bag inserted into the surgical area to allow the kidney to be pulled out.

The child is kept overnight in the hospital and discharged to home. There is no further need for routine/serial surveillance. The risk of hypertension or tumor arising from this kidney is eliminated. Many parents have elected this form of treatment since it puts closure on the issue. The other indications for surgery include a very large multicystic kidney that may cause difficulty with feeding or breathing due to its large size. It should be mentioned that this is a congenitally developed lesion and is not related to the adult condition known as adult polycystic kidney disease. For more information on laparoscopic nephrectomy see Minimally Invasive Surgery (Genitourinary).



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