Case Report Percutaneous nephrolithotomy of a staghorn stone in thoracic ectopic kidney Pratipal Singh, Vivek Vijjan, Manu Gupta, Deepak Dubey and Aneesh Srivastava Department of Urology and RenalTransplantation, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, India Abstract: Congenital thoracic ectopic kidney is a very rare developmental anomaly and the rarest form of all ectopic kidneys. It is usually asymptomatic and discovered incidentally on routine chest radiography. Herein we reported the first case of staghorn stone in a thoracic kidney managed successfully by percutaneous nephrolithotomy. Key words: ectopic kidney, percutaneous nephrolithotomy, renal stone, thoracic kidney. Introduction Ectopic intrathoracic kidney is a very rare form of renal ectopia and most are detected incidentally. We report the first case of symptomatic staghorn stone in an ectopic intrathoracic kidney managed by percuta- neous nephrolithotomy (PNL). Case report A 40-year-old man presented with history of dull aching left flank pain for 3 years. He had no other symptoms or comorbidity. He was evalu- ated by kidney-ureter-bladder (KUB) X-ray (Fig. 1), ultrasonography and intravenous urography of the KUB region. Imaging revealed a staghorn stone in an ectopic thoracic kidney with compact pelvica- lyceal system and a normally functioning, normally located opposite kidney. Plain and contrast-enhanced computed tomography (CT) scan confirmed a left ectopic thoracic kidney with staghorn stone and long renal vascular pedicle originating at the normal site (Fig. 2). The spleen was located inferior to the kidney and no other abdominal viscera herniated into the thorax. A left percutaneous nephrostomy (PCN) was placed through the posterior superior calyx with the help of an intervention radiologist under ultrasonic and fluoroscopic guidance prior to PNL. The superior calyx was punctured under ultrasonic guidance with a point of entry medial to the medial border of the scapula in the 10th intercostal space, avoiding lung injury. The tract was dilated over a guide wire under fluoroscopic control to place a 10-Fr nephrostomy catheter (Fig. 3). PNL was done through this established tract. The tract was dilated using Amplatz dilators up to 28-Fr, and 30-Fr Amplatz access sheath (Cook Urological, Spencer, IN, USA) was used for nephroscopy and stone fragmentation with the help of Swiss lithoclast. It was not pos- sible to clear the calculi of the inferior calyx through this tract, so a new PCN was placed on the third postoperative day through the posterior lower calyx. A re-look PNL was performed through this new tract (Fig. 4), during which all the calculi were cleared. The patient was stone free on postoperative KUB X-ray. He had no significant postoperative morbidity, did not require blood transfusion and was discharged uneventfully on the 10th postoperative day after nephrostomy removal. Chest X-rays after primary and relook PNL, and at the time of discharge after removal of nephrostomy did not reveal pneumo- or hydrothorax. Discussion Intrathoracic ectopia denotes either a partial or a complete protrusion of the kidney above the level of the diaphragm into the posterior mediastinum. Fewer than 5% of all patients with renal ectopia have an intrathoracic kidney. 1 This condition is to be differentiated from a congenital or traumatic diaphragmatic hernia, in which other abdomi- nal organs as well as the kidney have advanced into the chest cavity. There appears to be a slight left-sided predominance of 1.5:1, and the sex ratio favors male patients at a ratio of 2:1. 2 At the end of the eighth week of gestation when the kidney reaches to its adult location, pleuroperitoneal membrane separates the pleural cavity from the peritoneal cavity. It is uncertain whether delayed closure of the diaphragmatic analog allows for protracted renal ascent above the level of the future diaphragm, or whether the kidney over- shoots its usual position because of accelerated ascent before normal diaphragmatic closure. 3 The kidney usually lies in the posterolateral aspect of the diaphragm in the foramen of Bochdalek. The diaphragm at this point thins out, and a flimsy membrane surrounds the protrud- ing portion of kidney. Therefore the kidney is not within the pleural space, and there is no pneumothorax. 3 The adrenal gland is below the kidney in its normal location in most patients and in unilateral cases the contralateral kidney is usually normal. 3 No consistent associated anomalies have been described in other organ systems. Most cases are diagnosed incidentally and remain asymptomatic, and the main significance of such a kidney is the diagnostic dilemma it poses when identified as an incidental thoracic mass on routine chest radiography. 4 There are no data suggesting any predisposition for stone formation in these kidneys and there are limited reports on diagnosis and man- agement on nephrolithiasis in intrathoracic kidney.We could find only one previous case report on PNL for stone in an intrathoracic kidney, 5 and to our knowledge the present article is the first report on PNL for Correspondence: Aneesh Srivastava MS, MCh, Department of Urology and Renal Transplantation, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Raibarelli Road, Lucknow, Uttar Pradesh 226014, India. Email: aneesh@sgpgi.ac.in Received 29 November 2006; accepted 19 January 2007. International Journal of Urology (2007) 14, 558–560 doi: 10.1111/j.1442-2042.2007.01765.x 558 © 2007 The Japanese Urological Association