Malformations – Lymphatic Malformations – Sclerotherapy
Sclerotherapy is a treatment that has been effective in treating venous malformations and lymphatic malformations. The treatment consists of a percutaneous (through skin) injection of a substance into the abnormal veins of the venous malformation. The substance can be one of many that are able to irritate the wall of the vessel which results in the formation of a blot clot within the vessel. The blood clot will effectively stop the flow of blood through the blood vessel and if the irritation is severe enough, the blood vessel will be destroyed and replaced with scar tissue. These procedures are usually performed in an angiography suite, with the assistance of ultrasound guidance and ‘fluoroscopy’ or real-time x-ray monitoring. If sclerotherapy is the only treatment, several treatments may be necessary to accomplish this. The choice of sclerosant (substance used in the injection), will depend on the flow rate, the location of the lesion and the experience of the interventional radiologist. The more irritating the sclerosant, the more effective the treatment. This unfortunately is also accompanied by more potential side effects. The interventional radiologist must therefore weigh up the cost benefit ratio when selecting the most appropriate sclerosing agent.
In general, sclerotherapy is effective in treating macrocystic lesions (lymphatic malformations made up of predominantly large cysts) but less effective for microcystic lesions (lesions made up of small cysts). Substances used in sclerotherapy include OK-432, bleomycin, doxycline and a number of other sclerosing agents. These agents cause an irritation of the wall lining the lymph cyst which then becomes inflamed and shuts down. In order for the agent to be effective, it must come into contact with the lining of the cyst. This is much more difficult when dealing with microcystic lesions. Small doses of bleomycin have been successful in treating microcystic lesions. Sclerotherapy is administered in multiple sessions and this is done under general anesthesia.