British Journal of Radiology (2007) 80, e167-e169
© 2007 British Institute of Radiology
doi: 10.1259/bjr/79912069
Renal agenesis: report of an interesting case
A Mishra, MBBS, MD
National Organ Transplant Program, Tripoli Central Hospital, Tripoli, Libya
Correspondence: Dr Anuj Mishra, PO BOX 7913, Ainzara, Alfurnaz, Tripoli, Libya. E-mail: dranujmish{at}yahoo.com
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Abstract
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Renal agenesis is generally thought to result from a lack of induction of the metanephric blastema by the ureteral bud, which may be secondary to ureteral bud maldevelopment and/or to a problem with the formation of the mesonephric duct. Uncommonly, post-natal involution of multicystic dysplastic kidneys results in solitary kidney. Unilateral renal agenesis may be associated with ipsilateral genitourinary anomalies and VATER abnormalities. The interest of this case lies in the association of unilateral renal agenesis with the presence of an ipsilateral pelvic dilated ureter, ipsilateral seminal vesicle hypoplasia and absence of the vas deferens.
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Introduction
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Renal agenesis is a relatively common congenital anomaly, although its aetiology is unknown. Renal agenesis may be unilateral or bilateral. Bilateral renal agenesis/dysgenesis (BRA/D) is a rare anomaly occurring in only one or two per 10 000 births. Unilateral renal agenesis is usually an incidental finding with the contralateral kidney demonstrating compensatory hypertrophy. Renal agenesis is generally thought to result from a lack of induction of the metanephric blastema by the ureteral bud. Sometimes solitary kidney may be the result of post-natal involution of multicystic dysplastic kidney. Renal agenesis is associated with ipsilateral urogenital anomalies. Associated ipsilateral adrenal agenesis is seen in 8–10% of cases. An unusual case is reported here of unilateral renal agenesis associated with ipsilateral absence of the vas deferens and hypoplasia of the seminal vesicle and presence of an ipsilateral dilated pelvic ureter.
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Case report
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A 30-year-old young healthy man of normal build presented to the outpatients' department in surgery with vague abdominal pain of 6 months' duration, but not associated with colic. No significant past medical history was present. No history of urinary symptoms was elicited. Physical examination revealed a healthy individual of normal build. Systemic examination revealed mild fullness of the left renal angle. Routine laboratory studies including urine and stool examination did not reveal any abnormality.
Routine ultrasound examination showed an empty right renal fossa with compensatory hypertrophy of the left kidney. The right kidney could not be localized in the abdomen or pelvis. The distal third part of the right ureter was demonstrated with normal vesico-ureteric junction. The ureter was, however, dilated. The right seminal vesicle was hypoplastic and cystic compared with the contralateral seminal vesicle. The right vas deferens also was not visualized (Figure 1
). On multislice CT, the right kidney could not be seen in the abdomen or pelvis and the right renal fossa was occupied by colonic loops. CT angiography showed an absent right renal artery and renal vein. CT urography revealed absence of the right ureter and absence of filling of the dilated residual right ureter (Figure 2).
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Figure 1. The ultrasound shows(a) empty right renal fossa with compensatory hypertrophy of the left kidney with (b) associated blind-ending right ureteric stump and (c) hypoplastic cystic right seminal vesicle.
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Discussion
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Renal agenesis is a fairly common congenital anomaly with an unknown definite aetiology. Renal agenesis may be unilateral or bilateral. BRA/D is a rare anomaly incompatible with life, occurring in only one or two per 10 000 births. Despite it being a sporadic event, there is a male-to-female ratio of 3:1 and approximately 20–36% of BRA/D presents as familial recurrence. However, it is rarely diagnosed antenatally because of the virtual absence of the amniotic fluid.
Renal agenesis occurs when there is: (1) absence of the metanephric blastema; (2) ureteral bud maldevelopment; or (3) lack of induction of the metanephric blastema by the ureteral bud. Sometimes solitary kidney is the result of post-natal involution of multicystic dysplastic kidney and hydronephrotic kidney.
Predictably, the ipsilateral ureter and hemitrigone also fail to develop, although occasionally a blind-ending ureteric stump may be present, as in our case. Ipsilateral adrenal agenesis is seen in 8–10% of cases. Associated ipsilateral urogenital anomalies are common and include absence of the vas deferens, unicornuate uterus and absence or cysts of the seminal vesicle, as seen in our case. Other associated anomalies include skeletal abnormalities, anorectal malformations, cryptorchism and cardiovascular abnormalities. The classical association is seen in the VATER syndrome where developmental lesions may include vertebral and ventricular septal anomalies, anorectal atresia, tracheal and oesophageal lesions and radial bone abnormalities.
Unilateral renal agenesis is usually asymptomatic when it occurs as an isolated anomaly.
Occasionally, unilateral renal agenesis can be diagnosed on plain film by the absence of a renal outline and medial displacement of the colonic flexure into the renal bed. The contralateral kidney, when normal, shows compensatory hypertrophy and this may be visible on the plain film.
However, these features are easier to see on ultrasound. Often it may be difficult to differentiate between renal agenesis and a small atrophic kidney by ultrasound.
CT or radionuclide investigation demonstrating unilateral absence of renal tissue can be regarded as definitive. Moreover, a CT scan, besides demonstrating the absence of unilateral kidney, will also demonstrate other associated abnormalities. With the advent of multislice CT scans, a CT urogram can replace the conventional urogram.
Received for publication January 10, 2006.
Revision received March 22, 2006.
Accepted for publication April 24, 2006.
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References
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- Shukla AR, Kiddoo D, Kolon TF, Canning DA. The neonatal vanishing kidney: congenital and vascular etiologies. J Urol 2004;172:317–8.[CrossRef][Medline]
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Abstract
Introduction
