Nephroptosis: a cause of renal pain and a potential cause of inaccurate split renal function determination.

We present 3 cases of nephroptosis encountered in young females over a 6-month period which posed diagnostic difficulties and gave inaccurate split renal function determinations until the true situation was disclosed. A syndrome is described of clinical presentation with right upper quadrant pain, erect hippuran renography showing an apparently small right kidney and reduced function but with normal time to peak and elimination phase on the curve (the "miniaturised" renogram) and erect and supine DMSA scintigraphy which confirms the diagnosis of abnormal renal mobility. Guidelines are suggested by which nephroptosis can be recognised and assessed in urological and nuclear medicine practice.