Hydronephrotic obstructed kidney mimicking a congenital multicystic kidney: Case report with review of literature

Objective: To report a case of obstructed hydronephrotic kidney mimicking a multicystic kidney and to review the literature regarding differentiation of the hydronephrotic variant of multicystic kidney from the obstructed hydronephronic kidney. To suggest a possible algorithm in distinguishing them. Methods: We have reported a case of a 35-year-old male who presented with dull aching pain and a palpable right-sided cystic flank mass of several years duration. The initial workup suggested a nonfunctioning multicystic kidney while the operative findings and histopathology were suggestive of an obstructed hydronephrotic kidney with pyelonephritic changes. We searched the literature using the key words hydronephrotic dysplastic kidney and multicystic kidney. Results: A detailed literature search did not reveal any such publication describing the differentiation of the hydronephrotic multicystic dysplastic kidney from the obstructed hydronephrotic kidney of pelviureteral obstruction. We reviewed the existing literature on this subject, on the basis of which, we have suggested a six-stepladder approach to distinguish such cases. Conclusion: By using the 6 step ladder protocol algorithm suggested by us one can attempt to distinguish the hydronephrotic variant of multicystic dysplastic kidney from the hydronephrotic kidney due to pelviureteral obstruction in patients presenting with a symptomatic cystic flank masses of renal origin. Differentiation between the two may be difficult at times due to the medial/central placement of cysts in the former. This is necessary since renal salvage may be possible in the latter while timely nephrectomy may be considered in the former to prevent against the hazards of leaving behind a dysplastic kidney in situ.