Elsevier

Urology

Volume 63, Issue 4, April 2004, Pages 768-771
Urology

Pediatric urology
Nephrectomy for multicystic dysplastic kidney: if and when?

https://doi.org/10.1016/j.urology.2003.11.053Get rights and content

Abstract

Objectives

To evaluate the criteria for conservative versus surgical treatment of multicystic dysplastic kidneys and to attempt to specify the optimal timing for surgery, when considered indicated.

Methods

The study population comprised 48 antenatally or neonatally detected consecutive patients with unilateral multicystic dysplastic kidney. The fate of the affected renal conglomerate was regularly analyzed by ultrasonography. All cases were primarily followed up conservatively. In the patients who eventually underwent nephrectomy, the decision to operate was made after a minimum of 18 months (median 25).

Results

Ultrasound follow-up showed complete involution in 13 cases (27%); in 35 cases (73%), the renal conglomerate persisted throughout the study period (mean 46 months). Of the 48 patients, 32 (67%) eventually underwent nephrectomy. The size of the affected mass among the involuted cases was significantly smaller throughout the study period than in those requiring nephrectomy. The difference between the two groups continuously increased during follow-up, with a mean involution rate of 2.5 cm/yr versus 0.6 cm/yr (up to 18 months) for the involuted versus noninvoluted cases, respectively (P <0.0001). From 18 months on, no statistically significant involution was observed in those who eventually underwent nephrectomy.

Conclusions

Patients with antenatally or neonatally detected multicystic dysplastic kidney can primarily be followed up conservatively. Involution occurs in approximately one fourth of the cases, usually within about 14 months. In our experience, no significant involution can be expected to occur after 18 months. If surgery is decided on, we recommend an age of about 2 years. Late complications (eg, Wilms' tumor and renovascular hypertension) are rare.

Section snippets

Material and methods

Since 1989, a primarily conservative approach in the treatment of MDK has been adopted at the Hospital for Children and Adolescents, University of Helsinki. The study population comprised 48 consecutive patients with MDK treated between 1989 and 1999 at our institution.

MDK was defined as a renal tissue conglomerate, ultrasonographically consisting of cysts of variable size, with scanty or no identifiable renal parenchyma in between, and with no uptake on renal isotope scanning. MDK of the

Results

Complete involution of the multicystic conglomerate was observed by ultrasonography in 13 (27%) of the 48 patients. In 12 of the 13, involution occurred within 24 months, and in 1, it occurred at 51 months (median 14) of age. One patient with a conglomerate size of 7.5 cm at birth and a decrease to 2.2 cm at 36 months old was being followed up expectantly at the end of the study. Of the 32 patients who eventually underwent surgery, a reduction in the size of the cysts was observed in 19 (59%)

Comment

Our treatment plan was to follow-up our patients with MDK expectantly and to decide on nephrectomy after a follow-up period of a minimum of 18 months. The indication for surgery was an increased, unchanged, or only moderately decreased conglomerate size during the follow-up period. Consequently, 32 (67%) of the total of 48 patients eventually underwent surgery, 23 (72%) of these 32 within 30 months of follow-up.

Great variation in the prevalence of involution of affected units in MDK has been

Conclusions

Patients with antenatally or neonatally detected MDK can primarily be followed up conservatively. Involution within a reasonably acceptable time limit can be expected to occur in approximately one fourth of cases. In the remaining cases, usually no significant involution occurs after 18 months of age. Hence, if surgery is decided on, we recommend an age of about 2 years. Late complications (eg, Wilms' tumor and renal hypertension) are rare. Their significance in decision-making should not be

References (18)

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This study was financially supported by the Foundation for Pediatric Research, Helsinki, Finland and by the Medical Research Fund of Tampere University Hospital.

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