Unilateral multicystic dysplastic kidney with ipsilateral grade V vesicoureteral reflux: A case report of a rare association
Correspondence Address: Source of Support: None, Conflict of Interest: None DOI: 10.4103/0975-2870.218185
Keywords: Congenital anomalies of kidney and urinary tract, contralateral anomalies, multicystic dysplastic kidney, urinary tract infection, vesicoureteral reflux
Congenital anomalies of kidney and urinary tract, a major cause of childhood end-stage renal failure, encompass entities such as renal aplasia, hypoplasia, multicystic dysplastic kidney (MCDK), ureteric anomalies, and anomalies of the bladder and urethra.[1] We hereby present an interesting case of unilateral MCDK with ipsilateral Grade V vesicoureteral reflux (VUR) and normal contralateral kidney and urinary tract complicated by recurrent urinary tract infection (UTI) in a l-year-old male child. The cystic diseases of kidney pose diagnostic problems for clinicians, radiologists, and pathologists.
One-year-old male child presented with complaints of poor urinary stream and signs and symptoms of UTI in outpatient department of pediatrics. On general physical examination, child had weight of 8 kg and length of 76.5 cm with normal growth and development. He was normotensive and abdominal examination revealed right-sided renal mass and phimosis. The child was advised complete urine examination that showed pyuria without hematuria. On USG, the right kidney was shrunken, measuring 2 cm × 1.8 cm with dilated pelvicalyceal system and the left kidney measured 5.8 cm × 3.2 cm with normal pelvicalyceal system. Micturating cystourethrography revealed Grade V VUR on the right side without any evidence of obstruction in urinary system. No reflux or obstruction was seen on left side.99 Tc Dimercaptosuccinic acid renal scintigraphy demonstrated minimal tracer concentration in the right kidney indicating the absence of function and homogenous, uniform tracer concentration in left kidney suggesting normal function. Relative function of right kidney was estimated to be 1% and that of left kidney was 99%. On inquiry, the patient did not have any suggestive family history and no other congenital anomalies were found on examination. Cytogenetic studies were not performed. Subsequently, right-sided nephrectomy was performed in view of recurrent UTI due to ipsilateral VUR. Nephroureterectomy specimen was sent for histopathological examination. Specimen measured 4.4 cm × 2.5 cm × 1.8 cm and attached ureter measured 13 cm in length. Cut section showed cystically dilated sac-like kidney without recognizable pelvicalyceal system or corticomedullary demarcation. Renal parenchyma lining the cyst measured 0.6 cm in thickness without recognizable pyramids [Figure 1]. Cut section through ureter showed dilated lumen.
Microscopic examination showed disorganized architecture with dilated tubules and islands of immature cartilage, few ducts were surrounded by spindle cells resembling fetal blastema. Few primitive glomeruli and ductules were also seen [Figure 2]. Focal areas of lymphoid follicle formation and mild interstitial chronic inflammatory infiltrate were also present. Based on these features, diagnosis of MCDK was considered.
Cystic renal dysplasia is due to an abnormality in metanephric differentiation characterized histologically by persistence in the kidney of abnormal structures such as cartilage, undifferentiated mesenchyme, immature collecting ductules, and by abnormal lobar organization. Risdon [2] reviewed 150 cases of nephrectomy in children, of which 76 (51%) showed evidence of renal dysplasia on histopathological examination. Kessler et al.[3] reported involution rate of 73.6% and associated urologic abnormalities in 43.6% cases in their study on 23 infants with MCDK. Kuwertz-Broeking et al.[4] reported 97 cases of unilateral MCDK in children. Reported incidence of renal dysplasia varies from 1:1000 to 1:4300.[5],[6] Most cases of MCDK have unilateral presentation, and bilateral presentation is less common and is often fatal. Kessler et al.[3] in their study on 23 patients found that MCDK was present on left side in 14 patients and on right side in eight cases; however, Kuwertz-Broeking et al.[4] in their study experienced that in majority of the cases 55/97, MCDK affected right kidney. In the present study, the child had right-sided MCDK. Unilateral MCDK usually presents as renal mass in infants and children as in present case report, or it may present as chronic renal failure in childhood. Bilateral MCDK presents as severe disease and is associated with maternal oligohydramnios, neonatal renal, and pulmonary failure.[5] Renal dysplasia is most often sporadic but may also occur as a part of multiple malformation syndrome, rarely it may be familial or may be associated with malformation of Mullerian structures.[5] Pathogenesis of renal dysplasia involves ampullary function defect as demonstrated by Potter in her studies. Potter classified cystic diseases of kidney into four types and renal dysplasia malformation is categorized as Type II and Type IV. She believed that Type II malformations lacked significant nephrons and Type IV malformations are invariably associated with obstruction.[7] Later studies by Matsell et al.[8] and Shibata et al.[9] showed that some nephrons are formed in Type II malformations contradictory to Potter's belief. The present case belongs to Type II malformation, according to Potter's classification. It has been documented that there is dysregulation of PAX2 and Bcl2 cell survival genes in cystic renal dysplasia epithelia indicating altered patterns of apoptosis/proliferation and aberrant differentiation.[10] Grossly dysplastic kidneys have been classified as multicystic and aplastic dysplasia, hypoplastic dysplasia, segmental dysplasia, and diffuse cystic dysplasia. Microscopy of dysplastic kidneys shows islands of cartilage, which is believed to be derived from the fetal blastema and dysplastic ducts lined by columnar epithelium and surrounded by collars of spindle cells, believed to be the derivative of ampullary bud.[7],[11] Contralateral kidneys often undergo compensatory growth as was seen in 44 (45%) of 97 patients studied by Kuwertz-Broeking et al.[4] Abnormalities of contralateral kidney (reflux, pelvoureteral junction obstruction, megaureter dysplasia, renal agenesis) carry prognostic significance and their frequency varies from 20% to 40% in different studies.[4],[5] The presence of VUR in contralateral kidney has been discussed by many authors and in study by Kessler et al.,[3] it was the most common urologic abnormality seen in 22.1% of cases. In the present case report of unilateral MCDK, Grade V VUR reflux was present on ipsilateral side with normal contralateral kidney and urinary tract. Frequency of ipsilateral VUR is not discussed in most of the studies. Clinical complications in MCDK include abdominal or flank pain, UTI, hypertension, and rarely malignancy. A case of Wilms tumor in MCDK has been reported by Hartman et al.[12] Cases of renal cell carcinoma in 13 patients and a case of embryonal tumor in a 68-year-old patient is reported by Gordon et al.[13] An extremely rare case of orthotopic multicystic dysplasia with crossed fused renal ectopia was reported in a newborn infant.[14] Another case of unilateral MCDK with ipsilateral megaureter complicated by pyelonephritis was reported as an initial presentation in an adult patient.[15] Nephrectomy in patients with MCDK is considered if the patient has significant abdominal or flank discomfort, UTI involving the MCDK, hypertension due to MCDK or renal malignancy. MCDK associated with contralateral VUR has been reported by several authors; however, to the best of our knowledge, the present case is an unusual association of MCDK with ipsilateral VUR with normal contralateral kidney and recurrent UTI. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.
[Figure 1], [Figure 2]
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