If the ovarian cyst is 4cm in diameter, it depends on the specific nature of the cyst and then how to treat it. If it is a benign ovarian cyst 4cm in diameter, symptomatic medication can be administered, such as Gui Zhi Fu Ling capsule, to inhibit the growth and regular review. If it is a junctional or malignant ovarian cyst, regardless of the specific size, even a 4cm cyst should be treated with symptomatic surgery. In the case of junctional ovarian cysts, depending on the age and whether there is a need for fertility, the relevant ovarian cysts should be removed or the affected adnexa should be removed. In the case of malignant ovarian cysts, staging surgery for ovarian cancer must be performed, not just resection of ovarian cysts.