Percutaneous sclerotherapy of a symptomatic simple renal cyst in a child: observation of membrane detachment sign.

A 6-year-old girl with a symptomatic renal cyst underwent successful percutaneous aspiration and sclerotherapy with hypertonic saline under US guidance. Although membrane detachment sign was seen clearly during aspiration, it was confirmed to be a simple cyst. In contrast to previous reports, membrane detachment sign is not pathognomonic for hydatid cysts and may be seen after simple cyst aspiration. Therefore, differentiation of a symptomatic renal cyst from a hydatid cyst should not depend solely on membrane detachment sign. In either case US- or CT-guided percutaneous sclerotherapy should always be considered before surgery.