ectopic kidney

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with suspected congenital anomaly of the urinary tract. AP image from the excretory phase of a vintage intravenous pyelogram shows a normal position of the right kidney in the right renal fossa. The left renal fossa is empty and the left kidney can be found in the left pelvis, over the left side of the sacrum.The diagnosis was an ectopic kidney in the pelvis.

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Identification

of the cause of abdominal pain on CT in a patient with multiple incidental findings. Single ectopic malrotated right kidney with lobulation seen in Right iliac fossa drained by solitary renal vein.

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An ectopic kidney, also known as renal ectopia, is a congenital renal anomaly characterized by the abnormal location of one or both of the kidneys.

They can occur in several forms:

Epidemiology

The estimated incidence of an ectopic kidney varies by location:

one normal and one pelvic kidney - 1 in 3,000
crossed renal ectopia - 1 in 7,000
ectopic thoracic kidney - 1 in 13,000
solitary pelvic kidney - 1 in 22,000

Clinical presentation

Patients are most often asymptomatic. Normal pathology (e.g. infection, calculus) can affect ectopic kidneys, leading to non-classical abdominal pain. Ectopic kidneys are also prone to traumatic injury due to their abnormal location in the lower abdomen, pelvis or thorax.

Pathology

During normal embryological development, there is cephalic migration of the kidneys to their normal retroperitoneal location and an ectopic location is a result of arrested migration.

The kidney during its normal ascent has multiple aortoiliac branches, which degenerate when the kidney reaches its normal location. Here they develop new renal branches from the aorta. However, during an arrested ascent the ectopic kidney tends to retain some of the older aortoiliac vessels.

Associations

multicystic dysplasia in a fused or unfused crossed kidney
ureterocele
patent urachus
ectopic ureteral orifice
vesicoureteric reflux
vaginal agenesis
hypospadias
pelviureteric junction obstruction
multicystic dysplasia
variations may be in the number, position, shape and size or the rotation of kidney(s), calyces, ureter(s) or bladder
may be associated with anomalies of the vertebral column, lower gastrointestinal tract, genital tract or spinal cord and meninges

Radiographic features

Ultrasound

This is frequently the first modality to diagnose the ectopic kidney, which most often is incidentally detected.

CT

Contrast-enhanced CT scan depicts the vascular and non-vascular anatomy

IVP and MRI

May additionally help in the functional and structural assessment

Treatment and prognosis

Treatment options vary based on whether there are symptoms or complications. If an obstruction is present, surgery may be required for correction of the position of the kidney to allow better drainage of urine. In presence of extensive renal damage, nephrectomy is indicated.

Complications

hypertension is more frequently encountered in cases with more than one renal artery
infection and calculus formation may be more prevalent due to problems with urine drainage
if reflux is present then renal failure may result

Siehe auch:

und weiter:

Heterotopie

Assoziationen und Differentialdiagnosen zu Nierenektopie:

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Nierendystopie mit Verschmelzung

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