Australas Radio1 1992; 36: 271-273

Intrathoracic Right Kidney Diagnosed by Ultrasound R.J.ARCHER, M.R.C.P.,F.R.C.R. Department of Radiology St Thomas’ Hospital, London, SEI 7EH

ABSTRACT Intrathoracic kidneys are rare. A case is described in which the initial intravenous urogram performed for prostatism appeared to show a nonfunctioning right kidney. A subsequent ultrasound examination revealed that the right kidney was situated in the right hemithorax, well above the liver. Pelvic ectopic kidneys are common and standard teaching is to perform a full length film should a n immediate or 5 minute renal a r e a radiograph suggest an absentlnon-functioning kidney. With the increasing use of ultrasound in the initial assessment of patients with prostatism, the possible intrathoracic location of a kidney should be remembered when there is failure to demonstrate a kidney in the abdomen or pelvis. CASE REPORT An 89 year old man was referred to the Radiology Department for intravenous urography with a provisional diagnosis of carcinoma of the prostate. The 5 minute film showed no apparent excretion on the right, and a subsequent full length film taken at 20 minutes is shown in Figure 1.

FIGURE 1 - Full length 20 minute film from the IVU series showing apparent non-function on the right.

Key words: lntrathoracic kidney Renal ectopia Ultrasound Address for correspondence: Dr. R.J. Archer, M.R.C.P., F.R.C.R. Department of Radiology Royal Hobart Hospital GPO Box 1061 L Hobart Tasmania 7001 Australia Austrtilasian Radiology. Vol. 36, No.3 , August, 1992

Submitted for publication on: 23rd July, 1991 Accepted for publication on: 17th March, 1992

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R.J. ARCHER FIGURES 2, 3 and 4 - Images obtained from scanning laterally through the 5th right intercostal space. Owing to the 180 degree malrotation, the kidney is imaged in transverse sections, and the right lobe of the liver is in longitudinal section (longitudinal scan, patient’s head to the left). A = liver B = kidney.

FIGURE 2

FIGURE 3

The patient then underwent an ultrasound study of the renal tract. An echogenic mass, resembling renal tissue, was identified in the right hemi-thorax well above the liver, almost at the level of the scapula. (See Figures 2 , 3 and 4). A second injection of contrast medium was given and further views taken centering in the lower right chest. A tomogram from the second I.V.U. series i s shown in Figure 5, demonstrating a normal kidney lying transversely in the right hemithorax. A diagnosis of an ectopic intrathoracic right kidney was therefore made. DISCUSSION & LITERATURE REVIEW Intrathoracic renal ectopia is rare with approximately 178 cases described in the world literature by 1986 (1). Unlike low ectopic kidneys, intrathoracic kidneys usually remain asymptomatic and most reported cases represent an incidental finding on a chest radiograph (2). This is probably the first adult case to be initially diagnosed by ultrasonography, as the patient had no reason to have a chest radiograph prior to the IVU (3). On questioning, the patient reported not suffering from any major trauma and the only past history of note was oversewing of a peptic ulcer 20 years previously. Four basic types of intrathoracic kidney have been described: 1. True thoracic ectopia with a normally developed dorsal diaphragm.

2. Eventration of the diaphragm. 3. Congenital (Bochdalek’s) diaphragmatic hernia.

4. Traumatic rupture of the diaphragm with renal ectopia (1).

FIGURE 4

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An earlier review in 1972 found that the male to female ratio was four to one, the age range was thirteen days to eighty years with no significant peak age incidence, and the left to right ratio was approximately two to Australasian Radiology, Vol. 36, NO. 3, August, 1992

INTRATHORACIC RIGHT KIDNEY DIAGNOSED BY ULTRASOUND 1. In cases of apparent non-function

of a kidney at intravenous urography, if sonography is to be performed, then an intrathoracic site should be considered after scanning the flank and pelvis. This is also applicable to centres where sonography is used as the initial screening technique for patients being investigated for prostatism. 2. If ultrasonography is not immediately available then it may be worth performing a chest radiograph as well as a full length film to check for ectopia after non visualisation of one kidney on the five minute film. 3. Ultrasonography is a useful method of demonstrating intrathoracic renal tissue. ACKNOWLEDGEMENTS The author wishes to thank Dr A B Ayers of St Thomas’ for helpful advice with the manuscript, and Mr Tim Terry, Consultant Urologist, Leicester General Hospital, Gwendoline Road, Leicester, for permission to publish his patient. REFERENCES 1.

FIGURE 5 - Tomogram from the 2nd IVU series showing a normal kidney lying transversely in the right hemi-thorax.

2. 3.

one (4). Diagnostic difficulty is described in determining the relationship of the ipsilateral hemi-diaphragm to the ectopic kidney, and a diagnostic pneumoperitoneum has been recommended. The problem is that with both a congenital ectopic kidney and with eventration, the superior pole of the kidney is covered by a thin membrane which is not present after traumatic rupture, or with congenital (Bochdalek’s) or acquired herniae (4). It is interesting to note that no hemidiaphragm was demonstrated above the liver by ultrasonography in the patient described. The embryology of thoracic ectopia of the kidneys is disputed. Originally described in 1790 by Jean Louis Petit and later termed ‘eventratio diaphragmatica’ by Beclard, abdominal and retro-peritoneal contents may migrate into the topographical confines of the chest (5). It was previously thought that most Ausrmlasiun Radiology. Vol. 36, No. 3,August, 1992

intrathoracic kidneys were the result of maldevelopment of the pleuro-peritoneal membrane. However, the incidence of intrathoracic kidneys with diaphragmatic herniae is low, less than 0.25% (6). Spillane and Prather (7), proposed three criteria for the diagnosis of a congenital intrathoracic kidney. These were rotation anomaly, long ureter and anomalous high derivation of the renal vessels. As is the case with pelvic and horseshoe kidneys, medial deviation of the lower poles of the kidneys was described with intrathoracic ectopia (8). However, in the case decribed, there is complete 90 degree rotation of the kidney’s longitudinal axis. In the few cases described which have undergone selective arteriography, the renal vessels were shown to arise at the normal site (4). The lessons to be learnt from the reported case can be summarised thus:

4. 5.

6. 7.

8.

Donat SM and Donat PE. Intra-thoracic kidney: a case report with a review of the world literature, Journal of Urology 1988; 140 131-133. De Castro FJ and Schumacher H. Asymptomatic thoracic kidney. Clinical Paediatrics, 1989; 8: 279. Sumner TE Volberg SM and Smolen PM. Intrathoracic kidney-diagnosis by ultrasound. Paediatric Radiology 1982; 1 2 78-80. Malter IJ and Stanley RJ. The intra-thoracic kidney, with a review of the literature. Journal of Urology 1972; 107: 538-541. Ang AH and Chan W E Ectopic thoracic kidney. The Journal of Urology. 1972; 108: 2 11-212. Williams RG and Tillinghast AJ. Diaphragmatic herniation of the kidney; case report. Radiology 1949; 53: 566. Spillane RJ and Prather GC. Right diaphragmatic eventration with renal displacement; case report. Journal of Urology 1952; 68: 804. Gondos B. High ectopy of the left kidney. American Journal of Roentgenology 1955; 74: 295.

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Intrathoracic right kidney diagnosed by ultrasound.

Intrathoracic kidneys are rare. A case is described in which the initial intravenous urogram performed for prostatism appeared to show a non-functioni...
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