1. What are ovarian “chocolate cysts”? Ovarian “chocolate cysts” are a type of endometriosis. Ovarian “chocolate cysts” can involve only one ovary, but in about 50% of patients, both ovaries are involved. As the disease progresses, patients may experience dysmenorrhea, persistent lower abdominal pain, menstrual disorders, infertility and painful intercourse. 2. What causes ovarian chocolate cysts? Endometriosis is a common gynecological disease, the pathogenesis of which is still unclear. “The common clinical manifestations include dysmenorrhea, infertility, discomfort during sexual intercourse and abnormal menstruation, etc. If accompanied by rupture or torsion of the cyst, the corresponding manifestations of acute abdomen may also occur. A significant proportion of patients have no special discomfort and are only detected during routine check-ups or ultrasound examinations. 3. How can we determine if we have ovarian “chocolate cysts”? The diagnosis of endometriosis is mainly made by ultrasound and other imaging examinations. The specificity and sensitivity of ultrasound in the diagnosis of the disease (especially ovarian endometriosis) is over 95%, which is characterized by round or oval cystic masses with thick walls and fine light dots; in addition, some patients show a mild to moderate increase in serum glycoantigen 125 level. The gold standard for the diagnosis of this disease is laparoscopy. In addition, patients with ovarian endometriosis need to be differentiated from benign and malignant diseases of other ovarian origin, especially some plasmacytic/mucinous cysts or malignant tumors with intracapsular hemorrhage should not be differentiated; if preoperative abnormalities such as CA125 and HE4 are found to be significantly increased, the possibility of ovarian malignant disease should be highly suspected. 4. How to treat ovarian “chocolate cysts”? The treatment of patients with suspected endometriosis should take into account the patient’s age, diagnosis, location and extent of the lesion, fertility requirements, size of the lesion, etc. The fundamental purpose of treatment is to “reduce and remove the lesion, relieve and control pain, treat and promote fertility, and prevent and reduce recurrence”. For young patients with fertility requirements, if the mass is large, surgery to preserve fertility may be considered, with 3-6 months of postoperative drug therapy. For the route of surgery, transabdominal or laparoscopic surgery can be considered. The mode of surgery should be decided according to the technical characteristics of each hospital, and it is generally believed that laparoscopic surgery is the best surgical route available. During the perioperative period, attention should be paid to the prevention of infection and other symptomatic treatment.