Multicystic dysplastic kidney disease presenting with a single large cyst in a fetus-anatomical basis and radiological aspects

A Case of Multicystic Dysplastic Kidney Presenting as a Single Midline Pelvic Cyst

We present an unusual case of a female neonate presenting with a single midline pelvic cyst. Prenatal imaging was suggestive of multicystic dysplastic kidney (MCDK), but postnatal imaging was atypical for this diagnosis given the location and singular cyst noted. The patient ultimately underwent surgical exploration and was diagnosed with an ectopic MCDK. Ectopic MCDK should be considered in the differential diagnosis of unilocular cystic pelvic lesions identified in the perinatal period.

Neonatal multicystic dysplastic kidney with mass effect: A systematic review

INTRODUCTION

Multicystic Dysplastic Kidney (MCDK) is a common cause of palpable abdominal mass in a neonate, yet reports are few of resultant life-threatening extrinsic compression. This systematic review is the first to review all known neonatal MCDK cases complicated by external compression due to mass effect. Our aim is to foster communication about these unusual cases to inform management of future comparable cases.

METHODS

This systematic review followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Medical Subject Headings (MeSH) were used to search PubMed through June 8, 2021 as follows: ((((Polycystic Kidney Diseases/complications [MeSH Terms]) OR (Multicystic Dysplastic Kidney/complications [MeSH Terms])) AND (Humans [MeSH Terms]) AND (Infant, Newborn [MeSH Terms]) AND (Case Reports [Publication Type]) AND (("multicystic dysplastic kidney") OR ("multicystic kidney")))) OR ((unusual respiratory distress in newborn [Title]) AND (kidney)) OR (large MCDK). Resulting papers were screened and included if they reported neonatal MCDK complicated by external compression by mass effect. Excluded papers lacked an MCDK diagnosis, a neonatal patient, or clear indication of mass effect. Salient data was extracted from each case for comparison.

RESULTS

Of 51 papers screened, seven met inclusion criteria, presenting eight neonatal MCDK patients exhibiting varied combinations of symptoms secondary to external compression, including respiratory distress, gastrointestinal obstruction, and contralateral ureteral obstruction. All eight cases, ultimately managed with neonatal nephrectomy, had positive outcomes. Unreported and undiagnosed cases are not included in this review, making it susceptible to publication bias.

CONCLUSIONS

Large neonatal MCDK is typically managed conservatively, however it can be complicated by external compression due to mass effect. In this scenario, nephrectomy is a reasonable and definitive treatment. Less invasive management options may exist, e.g., aspiration with sclerotherapy. Communication about exceptional cases like these should be encouraged even when outcomes are poor.