Wandering kidney in dual-kidney transplant recipient presents a pitfall in the interpretation of renal scintigraphy.

A 26-y-old patient with end-stage renal disease and recent dual transplantation of cadaveric kidneys en bloc presented with increasing abdominal pain and a rising level of serum creatinine. An anterior-view (99m)Tc-mercaptoacetyltriglycine renogram demonstrated the typical overlap of the lower pole of the superior kidney and the upper pole of the inferior kidney. The renogram was consistent with vasomotor nephropathy. Subsequent imaging 1 wk later for worsening symptoms demonstrated a single reniform structure in the expected location of the inferior transplanted kidney, which was interpreted as a loss of perfusion to the superior kidney. Correlation with subsequent CT and sonography showed normal perfusion to both transplanted kidneys and that the superior kidney had wandered inferiorly, completely overlapping the inferior kidney on the anterior projection. The increasing prevalence of dual kidney transplantation warrants special attention to the potential for a wandering kidney.