What incidental finding makes donating a kidney in this case somewhat unwise?
Right sided renal agenesis with a solitary left kidney.
What is the approximate incidence of this abnormality?
Unilateral agenesis of kidney is seen in 1 in 500 live birth, while bilateral agenesis is a fatal condition, with incidence of 1 in 4000 live births
Did you notice any subtle morphological abnormality in any adjacent structure?
Right sided adrenal gland appears elongated (as it is not moulded properly due to absence of kidney), termed as 'low lying adrenal sign'. Also, right renal artery is absent.
Other than renal agenesis, what can lead to absence of a kidney in its usual location.
Nephrectomy is the most common cause of an absent kidney in an elderly affluent population and if surgical clips have not been used, it can be difficult to identify surgical change. Identifying a renal artery stump is helpful. A pelvic (ectopic) kidney or cross-fused renal ectopia should also be considered.
CT of the abdomen demonstrates a solitary left kidney, with physiological hypertrophy. The morphology of the left kidney is normal. The right renal bed is empty, with no evidence of prior surgery or renal tissue.