Only symptomatic or complicated cysts (hemorrhaging, infected, ruptured, displacing or compressing the bile duct system or other organs) should be treated. The simplest method is the CT-guided aspiration of cyst contents, possibly with subsequent obliteration of the cyst with Ethoxysklerol or alcohol. Unfortunately the recurrence rate with this method is very high (up to 50%). Surgical removal of the roof of the cyst is much more effective. 1991 the first minimally invasive surgery (laparoscopy) was performed. In minimal invasive surgery the roof of the cyst is removed (after the cyst has been drained of its contents) through three small incisions (umbilical and middle / upper abdomen). The remaining cavity is then covered with omentum majus, which is sewn to the edge of the cyst. This prevents the formation of a new cyst. Compared to the interventional procedure (puncture and sclerotherapy) results in minimally invasive surgery have a much lower relapse rate (11%).