Ann Thorac Surg 2008;86:651-654. doi:10.1016/j.athoracsur.2008.02.036
© 2008 The Society of Thoracic Surgeons
Case Reports
Bilateral Intrathoracic Kidneys and Adrenal Glands Associated With Posterior Congenital Diaphragmatic Hernias
Michael W. Dingeldein, MDa,
Derek Kane, MDe,
Anthony W. Kim, MDb,
Rashmi Kabre, MDa,
Maurice J. Pescitelli, Jr, PhDd,c,
Mark J. Holterman, MD, PhDa,c,*
a Department of General Surgery, Rush University Medical Center, Chicago, Illinois
b Department of Cardiothoracic-Vascular Surgery, Rush University Medical Center, Chicago, Illinois
c Department of Surgery, University of Illinois at Chicago, Chicago, Illinois
d Department of Cell Biology and Anatomy, University of Illinois at Chicago, Chicago, Illinois
e Department of Surgery, Medical College of Wisconsin, Milwaukee, Wisconsin
Accepted for publication February 12, 2008.
* Address correspondence to Dr Holterman, 840 S Wood St, M/C 958, Department of Surgery, University of Illinois at Chicago, Chicago, IL 60612 (Email: rmasjet{at}uic.edu).
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Abstract
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We present a case of bilateral intrathoracic kidneys and adrenal glands associated with bilateral posterior diaphragmatic defects in a symptomatic 18-month-old baby boy. The diaphragmatic defect did not appear to be the typical posterolateral diaphragmatic hernia of Bochdalek. The patient underwent primary surgical correction through an abdominal approach. Postoperatively, the patient enjoyed an uneventful course and was discharged home without any further events. We discuss this report of bilateral intrathoracic kidneys associated with bilateral diaphragmatic hernias, we describe the operative management, and we analyze the possible embryological development of this defect.
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Introduction
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Ectopic kidneys are not an uncommon phenomena occurring in 1% of postmortem examinations, but complete intrathoracic cases are very rare representing only 5% of all renal ectopia. These are usually asymptomatic in males (2:1), located on the left side (1.5:1), and are diagnosed in all ages [1, 2]. Only about 150 cases of thoracic kidneys have been reported in the last century, and of these only four have been bilateral [1]. No other case of complete bilateral intrathoracic kidneys and adrenal glands with congenital diaphragmatic hernias (CDHs) was found in the literature. We present the case of an 18-month-old baby boy with bilateral intrathoracic kidneys and adrenal glands associated with posterior diaphragmatic defects that did not seem to be consistent with the classic Bochdalek diaphragmatic hernia.
The patient is an 18-month-old Hispanic, male baby who was delivered at full term to a G2P1 mother by cesarean section. He was treated for recurrent tonsillitis and upper respiratory tract infections with a tonsillectomy and adenoidectomy. After his surgery, there was substantial difficulty in extubating the patient. The chest roentgenogram demonstrated the presence of a left retrocardiac silhouette. A computed tomographic scan was performed to delineate the abnormality and this demonstrated the presence of bilateral diaphragmatic herniation of the adrenal glands and kidneys into the thorax with greater left-sided versus right-sided involvement (Fig 1). The impaired pulmonary function was likely due to either bad diaphragm function or decreased lung volume from the space-occupying effect of the kidneys.
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Fig 1. Coronal view of chest computed tomographic scan demonstrating bilateral intrathoracic renal and adrenal glands.
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The patient ultimately underwent surgical repair of his bilateral diaphragmatic hernias through a transverse upper abdominal incision. This approach was selected to control the abdominal aortic renal blood supply proximally. The renal vasculature appeared to originate from their normal anatomic position (ie, abdomen aortic position) (Fig 2).
The right-sided diaphragm repair was performed before the left-sided repair due to concerns that severe distraction of the left renal vessels would preclude the safe dissection and mobilization of the left kidney and adrenal glands. Fortunately, both kidneys and adrenal glands were easily mobilized and retracted back into the abdominal cavity with no obvious kinking of the vasculature (Fig 3). The defects in the diaphragm were posterior, without a lateral component. During the repair, an intact membrane between the anterior surface of the ectopic kidneys and the pleural cavity was identified that prevented complete herniation of the abdominal viscera into the pleural space. The repair of the bilateral diaphragmatic hernias was otherwise relatively straightforward. The posterior aspect of the right and left diaphragms was sewn with minimal tension to the posterior thoracic and abdominal wall using interrupted nonabsorbable pledgeted sutures. The patient enjoyed an unremarkable postoperative course. He was ultimately discharged home on postoperative day 7.
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Comment
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The unique feature of this case is the bilateral intrathoracic kidneys and adrenal glands associated with bilateral posterior congenital diaphragmatic hernias. Intrathoracic ectopic kidneys are exceptionally rare. Pelvic or inferior ectopic kidneys are far more common than superior displacement. Congenital superior ectopic kidneys (as opposed to traumatic displacement secondary to diaphragm rupture that would be considered acquired superior kidneys) have been divided into the subgroups infradiaphragmatic, transdiaphragmatic, and supradiaphragmatic (also referred to as intrathoracic). Supradiaphragmatic kidneys can be associated with or without an intact diaphragm [1, 3].
The exact cause of CDHs is unclear. Embryologically the diaphragm has four components: (1) septum transversum (central tendon) developed from the anterior thorax, (2) pleuroperitoneal membranes developed from the posterior thorax, (3) dorsal mesentery of the esophagus, and (4) muscular components developed from the body wall [4]. Many experts believe failure of the pleuroperitoneal membrane to completely fuse with the septum transversum leads to congenital diaphragm hernias of the Bochdelak type. Intrathoracic kidneys can be associated with CDHs in two ways (ie, either by direct herniation through the diaphragm defect into the pleural space or by location in the posterior mediastinum due to a true embryologic ectopia independent of the diaphragmatic defect).
The adrenal gland association with intrathoracic kidneys and CDHs has not been well reported. Many early case reports of intrathoracic kidneys do not mention the adrenal glands. N'Guessen and colleagues [1] analyzed 18 case reports of thoracic kidneys and found that in 14 cases there was no mention of the adrenal glands. Of the remaining four cases, two reported the normal position of the adrenal gland and two reported associations with the thoracic kidney. It has been suggested that the adrenal gland determines final renal position, but there have been case reports of unilateral thoracic kidneys with and without thoracic adrenal glands [2].
The exact mechanism of intrathoracic kidney development is unknown, but many hypotheses have been proposed. It is well known that the diaphragms are developed by approximately the eighth week in utero and the kidneys finish their superior migration by the fifteenth week [3, 4]. Earlier case reports proposed that the superior kidney ectopia was due to continued cranial migration from a lack of physical boundary when the pleuroperitoneal membranes fail to fuse. However, this was disputed as unlikely because only a very small percentage of CDHs have thoracic kidneys, and there are only case reports of intrathoracic kidneys with intact diaphragms [1]. Another previous explanation has suggested that traction on the ascending kidney from adhesions may create a pathway for the kidney to migrate into the thorax. The metanephron continues to postnatally migrate, thereby potentially affecting the development of the diaphragm, leaving a potential pathway into the thoracic cavity [5–7].
Another explanation, possibly one of the most intriguing ones, involves the interaction between the mesonephros and metanephros. Delayed involution of mesonephric tissue, thus the extension of the renal development tract, has been hypothesized to be the source of malposition. This is based on a case report of a right intrathoracic kidney with vertebral abnormal fusion [8]. It is known that as the metanephric blastema migrates cranially, the mesonephric tissue involutes in the opposite direction, and their meeting (ascension and involution) is the final resting place of the kidney.
Irrespective of the cause of intrathoracic kidneys, it is clear that final kidney position is an active and complex process and not merely a passive result of embryo elongation. As previously stated, this case presents the unique finding of asymptomatic bilateral intrathoracic kidneys and adrenal glands associated with posterior diaphragmatic defects. We believe that this has not been previously reported. The case presented in this report supports an embryologic explanation based on a mismatch between active metanephric migration and fusion of the pleuroperitoneal membranes with the septum transversum, normally a process that is carefully choreographed.
We suspect that the diaphragmatic defects in this case occurred because of the ectopic position of the kidneys, which prevented the posterior fixation of the diaphragm. This would explain the intact membrane between the ectopic kidneys and the pleural cavity because the parietal pleura or the peritoneum, or both, would not have formed normally, as it was distracted by the ectopic kidneys. In most cases, a classic bilateral Bochdalek defect with visceral herniation would have been symptomatic from birth, secondary to significant pulmonary hypoplasia. This patient clearly had a distinct type of diaphragmatic hernia, dissimilar from the Bochdalek type, which is most likely a result of the ectopic position of his kidneys. Thus, we believe kidney development affected the diaphragm development and not vice versa. The prognosis for our patient was excellent, and still is excellent, given the asymptomatic presentation, the relatively straightforward repair and recovery, and the absence of any concomitant anomalies.
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Acknowledgments
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The authors thank Charlotte Hammond for her excellent artistic ability.
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References
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- N'Guessen G, Stephens FD, Pick J. Congenital superior ectopic (thoracic) kidney Urology 1984;24:219-228.[Medline]
- Donat SM, Donat PE. Intrathoracic kidney: a case report with a review of the world literature J Urol 1988;140:131-133.[Medline]
- Sozubir S, Demir H, Ekingen G, Guvenc BH. Ectopic thoracic kidney in a child with congenital diaphragmatic hernia Eur J Pediatr Surg 2004;15:206-209.
- Lally KP. Congenital diaphragmatic hernia Curr Opin Pediatr 2002;14:486-490.[Medline]
- Fleischner FG, Robins SA, Abrams M. High renal ectopia and congenital diaphragmatic hernia Radiol 1950;55:24-26.
- Liddel RM, Rosenbaum DM, Blumhagen JD. Delayed radiologic appearance of bilateral thoracic ectopic kidneys Am J Roentgenol 1989;152:120-122.[Free Full Text]
- Jefferson KP, Persad RA. Thoracic kidney: a rare form of renal ectopia J Urol 2001;165:504.[Medline]
- Angulo JC, Lopez JI, Vilanova JR, Flores N. Intrathoracic kidney and vertebral fusion: a model of combined misdevelopment J Urol 1992;147:1351-1353.[Medline]
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Abstract
Introduction
