Urinary milk of calcium in children and adults: use of gravity-dependent sonography.

Fifteen cases with urinary milk of calcium (UMC) are presented, all of them secondary to urinary obstruction: ureteropelvic junction stenosis (three cases), staghorn calculus (two), caliceal diverticulum (five), and pyelogenic cyst (five). Four patients (aged 7-19) are the youngest with this affliction reported to date. Milk of calcium proximal to a staghorn calculus has not been described previously. Gravity-dependent sonography was the most efficient and sensitive method of diagnosis. Follow-up of 1-16 years showed the formation and gradual increase in the quantity of UMC without evidence of gross calculus formation within the milk. In two patients, there was spontaneous, partial drainage of UMC.