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Megacalycosis

Fundamentals and Symptoms of Megacalycosis

Definition:

Megacalycosis is a rare, congenital, nonobstructive dilatation of the renal calyces with a normal renal pelvis and ureter, and without vesicoureteral reflux.

Epidemiology:

Very rare, usually unilateral, and more common in men than in women.

Pathophysiology of Megacalycosis:

The malformation of the renal medulla leads to short collecting ducts and an increased number of calyces. Megacalycosis causes a mild disturbance of the maximum concentration capacity of the kidney, the long term prognosis in relation to renal function is good.

Signs and Symptoms:

In general, no complaints.

Diagnostic Workup of Megacalycosis

Most common an incidental finding on imaging. The key point is to distinguish megacalycosis from obstructive hydronephrosis or ureteropelvic junction obstruction.

Sonography:

Dilatation of the upper urinary tract limited to the calyces.

CT or MR urography:

Best imaging study for the differential diagnosis of urinary tract ectasia. Typical findings are nonobstructive calyceal dilatation with a normal renal pelvis and normal ureter.

Intravenous Urography:

Intravenous urography shows an enlargement of the pyelocalyceal system and increased calyces. There is no ectasia of the renal pelvis and ureter [fig. Megacalycosis in intravenous urography].

VCUG:

No vesicoureteral reflux in voiding cystourethrography; the study is mainly useful in unclear cases or in children.

Renal Scintigraphy:

Renal scintigraphy reveals sormal renal function with rapid washout of the radionuclide.

Megacalycosis: intravenous urography shows an increased number and dilatation of the calyces. With kind permission, Dr. G. Antes, Kempten.

Treatment of Megacalycosis

Specific treatment is unnecessary.

  Deutsche Version: Megakalikose

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