Giant cystic abdominal masses in children and adolescents: ultrasonic differential diagnosis.

Twelve children and adolescents with a variety of giant cystic abdominal masses are described. These masses are easily evaluated by ultrasonic scanning. Information regarding location, size, origin, and internal structure aid in the differential diagnosis. A correct diagnosis was made in a high percentage of the cases, obviating the need for more invasive studies. Ultrasound examinations at appropriate intervals during patient management can document change in position and/or size.