|Year : 2000 | Volume
| Issue : 1 | Page : 32-35
Congenital unilateral multicystic dysplastic kidney in children: A clinical study
Arun K Sharma, KN Rattan, Nirmala Sharma
Department of Paediatric Surgery, Postgraduate Institute of Medical Sciences, Rohtak, India
Arun K Sharma
c/o B.L. Sharma, 5-A, Double Storey, Tansen Nagar, Gwalior - 474 002
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Multicystic kidney is one of the most frequently encountered masses in the newborns, ranking either first or second in occurrence. Totally 15 cases were managed over the last 5 years. The most common age of presentation was within first month of life, the affliction occurring more on the left side. Commonest mode of presentation was abdominal mass. Ultrasonography was the diagnostic investigation of choice. Five cases were diagnosed antenatally. Associated anomalies were found in 8 cases with anovestibular fistula, PUJO in contralateral kidney, right congenital lumbar hernia and oesophageal atresia with TOE. Nephrectomy was the surgical treatment performed along with appropriate management of the associated anomalies.
Keywords: Multicystic Dysplastic Kidney; Unilateral; Children
|How to cite this article:|
Sharma AK, Rattan K N, Sharma N. Congenital unilateral multicystic dysplastic kidney in children: A clinical study. Indian J Urol 2000;17:32-5
| Introduction|| |
Cystic lesions of the kidney present a variety of forms in infants and children. Multicystic kidney disease is a well-defined group of unilateral and occassionally bilateral cases.  It is a developmental anomaly of the kidney in which renal parenchyma is replaced by tense non-communicating cysts and the proximal ureter is atretic or nonpatent. In 1936, Schwartz  first described multicystic kidney disease but the characteristics of the disease was first described by Spence in 1955. 
Different theories were advanced as to the etiology of renal cyst formation. The original "failure of union" theory of Hilderbrant, the "persistence of vestigeal structures" thesis of Kampmeier and "the localised urinary obstruction plus vascular impairment" mechanism postulated by Hepler. None seems universally satisfactory or acceptable. Actually all that can be stated definitely in this regard is that muticystic kidney is a congenital defect resulting from foetal maldevelopment not on a hereditary basis.
A review of the patients at our institution in whom a multicystic kidney had been diagnosed was undertaken and the results of this study and those in literature are discussed in relation to the overall management of the asymtomatic multicystic dysplastic kidney (MCDK).
| Patients and Methods|| |
During a 5-year-period 15 children with multicystic dysplastic kidney who underwent surgical treatment were identified. Of the 15 cases, 5 were diagnosed antenatally via ultrasonography while 5 were less than one month of age and 4 were less than 4 years of age. Only one of the case presented at 12 years of age in our series [Table 1]. Male patients were predominant (9:6). A family history concerning the renal disease was absent in all the 15 cases. The left kidney was affected slightly more often than the right kidney (10:5).
| Results|| |
5 cases were diagnosed antenatally by ultrasound while rest 10 presented with a flank or abdominal mass which was the commonest mode of presentation. Of the 15 patients with multicystic dysplastic kidney 12 had unilateral disease with normal opposite kidney while 3 had PUJ obstruction on the contralateral side. On routine abdominal palpation in an otherwise healthy infant a large, unilateral, lobulated, non-tender movable mass is found in the flank [Figure 1]. Four patients were admitted primarily for the treatment of congenital anomalies and multicystic kidney were diagnosed during work up of the patients [Table 2]. Urine examination was found to be normal in 12 cases while in 3 cases, urine was infected and positive cultures of B.coli or B. proteus were obtained. Blood urea and serum creatinine was found to be normal in all the cases.
Ultrasonography is the investigation of choice which is non-invasive and establishes the diagnosis in almost all cases, including antenatal diagnosis. Most significant finding on excretory urography were non-opacification of the kidney mass with a normal or hydronephrotic contralateral kidney in 3 cases which was associated with PUJO. Associated anomalies found were urologic and non-urologic. Urologic anomalies included contralateral ureteropelvic junction obstruction in 3 cases while hypospadias was present in one of the cases. Non-urological anomalies included anovestibular fistula in 3 cases, oesophageal atresia with TOF in 1 case, right congenital lumbar hernia in 1 case [Table 2]. Cystourethroscopy was done showing complete absence of the ureteric orifice in the bladder on the side of lumbar mass and arrest of the catheter in the ureter at varying levels during catheterisation on the side of lumbar mass.
Nephrectomy was performed by transperitoneal approach in all the 15 cases after demonstration of a lifesupporting contralateral kidney.
The multicystic kidney removed does not have a reniform outline on gross examination but consists of a grapelike cluster of cysts held together by connective tissue [Figure 2]. The size of the cysts varies and so also the number. Cut-section showed thin-walled cysts around a small nubbin of solid or spongy tissue near the centre [Figure 3]. Although there was no apparent communication between the cysts  but some authors have reported that these cysts may communicate with one another. 
The ureter is atretic [Figure 4] in 13 cases and in 2 cases the ureter was found to be entirely absent and was represented by a very thin fibrous strand. All the multicystic kidneys presented with a histological picture of the presence of primitive renal elements often surrounded by loose embryonic mesenchyme. The walls of the cyst were composed of fibrous tissue and the epithelial lining was found to be flat or cuboidal.
| Discussion|| |
The term "unilateral multicystic kidney" was first proposed in 1936 by Schwartz.  All the 15 cases in our series MCDK were unilateral but bilateral cases can also occur.  Most common age of presentation was within first month of life and 5 cases were diagnosed antenatally by ultrasonography. It is possible that approximately three-quarters of the unilateral multicystic kidneys remained undiagnosed in the days before pre-natal ultrasound diagnosis.  The incidence of unilateral multicystic kidney was 1 in 4300 live births. The incidence of unilateral renal agenesis in the adult population has been reported variably to be between 1:1500 to 1:2000. , It is possible that a significant proportion of these cases are in fact the end result of involution of a muticystic kidney.
Male patients were predominant,  although some say that there is no predilection for side or sex. 
Commonest mode of presentation was lump in the abdomen. There was no evidence of pain or discomfort due to lump, - it did not cause any disturbance of micturition being excluded from the urinary tract. Ultrasonography was the investigation of choice in our series and 5 of the cases had been diagnosed by pre-natal ultrasonography.
Investigation: Most significant finding on excretory urography was non-visualisation of muticystic dysplastic kidney with a normal-appearing kidney on the opposite side. Classically renal function is absent in MCDK and there should be no detectable concentration of radiographic contrast medium. , In recent years the phenomenon of the total-body-opacification phase of highdose urography has been used in new borns as a diagnostic aid. Some multicystic kidneys might, indeed, be capable of minimal function adequate to visualize radiographically although insufficient to support life. We did renal isotope scan in 3 cases; no function was seen in MCDK. Cystoscopy and attempted retrograde urography when performed in the reported cases have shown either an absence of the ureteral orifice on the side corresponding to the lesion or a blind termination of a small ureter below the ureteropelvic junction.
Treatment: The most appropriate management of the multicystic dysplastic kidney remains controversial. Nephrectomy was done after demonstration of a life-supporting contralateral kidney in all the cases. The transperitoneal approach was preferred since it has certain advantages in the early control of blood supply, avoidance of injury to adjacent viscera and abdominal exploration particularly of the opposite kidney is possible.
Long-term finding show that MCDK may take as long as 20-25 years to resolve; families and physicians should be prepared for long-term follow-up (Wacksman 1993) which is not possible in Indian circumstances.
The controversial issue is the long-term risk of the development of malignancy in the MCDK. Nodular renal blastema is a part of the nephroblastomatosis complex and it bears an association with Wilm's tumor. Such blastemal elements are considered to be precursor lesions to Wilm's tumor according to the "2 hit" theory of Knudson and Strong.  The true incidence of nodular renal blastema is increased in multicystic dysplasia and it is in the range of 3-5 percent.  One must accept that there is a risk for the development of neoplasia although it appears to be small. From 1966 to 1986 - 6 reports of malignancy associated with MCDK had been reported. Flow cytometric evaluation of MCDK demonstrated a diploid pattern of deoxyribonucleic acid. But these findings do not support or negate the potential for neoplasm associated with MCDK. Since a diploid deoxyribonucleic acid pattern does not eliminate the possibility of the future development of malignancy.  Hypertension has been reported in 4 children with retained MCDK. 
The most pressing of these issues in Indian circumstances seems to be how to assure life-long surveillance and also that they are not lost to follow-up. It would seem that life-long surveillance will probably be less than successful in a large number of cases and in that regard operative removal of the MCDK would be definitive. Also it would appear that in experienced hands, anaesthetically and surgically the risk of removing a MCDK is small and perhaps even smaller than the incidence of development of Wilm's tumor if the organ is retained.  We believe clearly that surgery is the best option in those children in whom the retained mass appears to be growing, hypertension develops, the diagnosis is in question or adequate follow-up can not be assumed. Since the multicystic dysplastic kidney is unilateral, the prognosis is good.
Follow-Up: All the 15 cases are under follow-up. We did ultrasonography after 3 months to rule out any multicystic changes in the opposite kidney. Routine urine examination and renal function test like blood urea and serum creatinine must be carried out every month. There was no mortality in our series.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2]