Case Study - October 2012
This 62 yr old male was referred to the haematuria clinic with visable
- What are the 2 main findings on the CT?
- What is the incidence of the congenital anomaly?
- How does it arise?
- What genetic conditions can this be associated with?
- What symptoms do these patients have?
1. There is a 7x5 mm stone in the isthmus of a horseshoe kidney.
2. It is the most common kidney fusion anomaly and affects 1 in 500, with a M:F ratio of 2:1.
3. There are two theories:
a. The horseshoe kidney is formed during organogenesis, when the inferior poles of these early kidneys touch, fusing in the lower midline.
b. Alternatively, horseshoe kidneys is the result of a teratogenic event involving the abnormal migration
of posterior nephrogenic cells, which then coalesce to form the isthmus and hence abnormal fusion of the kidneys.
4. Turners Syndrome (15%) and Trisomy 18.
5. Patients are usually asymptomatic , so these are usually picked up incidentally. Vesicoureteral reflux is present in about half of patients and ureteral duplication in 10%. Hypospadias or undescended testis is present in 4% of males and bicornuate uterus or septate vagina is present in 7% of females. Patients may have an increased incidence of stones and infections. There is an increased risk of Wilms tumour and carcinoid tumour. The horseshoe kidney is also more prone to trauma as it is not protected by the rib cage.