Sclerotherapy is a nonsurgical way to treat certain types of vascular malformations, which are abnormal clusters of blood vessels or lymphatic channels that occur during fetal development.

Using X-ray and ultrasound equipment, a doctor called an interventional radiologist places a small needle into the vascular malformation and injects a chemical called a sclerosant. The sclerosant causes inflammation and eventual shrinkage of the malformation. There are several different sclerosants the doctor may use, depending on the type of malformation being treated and the location within the body.

Depending on the size and shape of the malformation, more than one injection may be needed. The procedure usually takes about an hour, although its beneficial effects may not be seen for up to one to two months.