Simple Renal Ectopia: a Multidetector Computed Tomography Study

Address for Correspondence: C.S. Ramesh Babu, Associate Professor of Anatomy, Muzaffarnagar Medical College, N.H.58, Opp. Begrajpur Industrial Area, Muzaffarnagar251203 (U.P), India. Mobile: +91-9897249202 E-Mail: [email protected] Background: When the kidney is not located in its normal position in the renal fossa, but located in an abnormal position on the same side, it is referred to as Simple renal ectopia. Migration of a kidney to the contralateral side is referred to as Crossed Ectopia. Simple renal ectopia can be unilateral or bilateral and is due to the partial arrest of normal renal ascent or excessive ascent. The reported incidence of simple renal ectopia is 1:500 to 1:1100 cases and is more prevalent on the left side without any significant difference in between the sexes. Though ectopic kidneys may remain asymptomatic, they are more susceptible to develop hydronephrosis and renal calculi. Materials and Methods: We have retrospectively reviewed multidetector computed tomography angiographic scans of 960 patients (491 males; 469 females). Observations: We have observed simple renal ectopia in seven patients (5 males and 2 females; 0.73%) which is higher than the reported incidence. We have observed 4 kidneys in pelvic, 2 in lumbar and 1 in iliac position. Out of 7 ectopic kidneys, 5 were on the left side and 2 on the right side. Hilum was abnormally positioned in all ectopic kidneys due to disturbance in axial rotation. In three cases the ectopic kidneys received arterial supply from the contralateral arteries arising from aorta or common iliac arteries which is a rare phenomenon. Renal calculi and hydronephrosis were noted in two cases. Conclusion: Presence of an ectopic kidney might result in an atypical pattern of referred pain which may be confused with appendicitis or pelvic inflammatory disease, especially in women. Presence of an ectopic pelvic kidney can lead to complications during pelvic surgeries. Multidetector computed tomography angiography is an excellent imaging modality not only useful to define prevalence of renal ectopia in general population but also to detect associated complications and vascular anomalies in a single investigation.