In recent years, endometriosis is a chronic disease, the incidence of which has been increasing year by year in recent years with a trend toward younger age and an increasing rate of malignant transformation, seriously affecting the physical and mental health and quality of life of female patients; endometrioid carcinoma and clear cell carcinoma are the two most common pathological types of malignant transformation of ovarian endometriotic cysts, but cases of malignant transformation in other sites have also been continuously identified and reported, such as abdominal wall scars, intestinal tract, vaginal-rectal compartment, etc. It is now thought that it may be related to metabolic, genetic and other factors. Two cases of malignant endometriotic cysts are described below: The patient was 57 years old and was admitted to the hospital with a pelvic mass that had been found for 10 years. The patient had been naturally menopausal for 4 years, and before menopause, gynecologic ultrasound in 2000 suggested bilateral ovarian cysts, without dysmenorrhea and menstrual changes, without fever or abdominal pain, and no special treatment was given, after which the mass persisted with no significant changes, and after menopause, the results were reviewed regularly as before; in early July 2015, she developed lower abdominal cramping and discomfort, intermittently, and was referred to an outside hospital for gynecologic ultrasound The left adnexal cystic mass was 7 cm in extent, oval in shape, with a wall thickness of about 0.2 cm and visible internal separation. Gynecological examination: a cystic mass with a diameter of 7 cm, smooth surface and poor mobility was palpable in the left adnexal region; pelvic MRI: cystic mass in the left adnexal region with irregular margins and visible separation and heterogeneous T2, T1 high and low mixed signals in the mass, suggesting a cystic mass in the left adnexal region, malignant lesion was not excluded; laparoscopic surgery was performed and the microscopic findings were: cystic enlargement of the left ovary with a diameter of about 7 cm, with the posterior lobe of the broad ligament and the intestinal canal. The right ovary cystic enlargement was about 4 cm in diameter and adhered to the posterior lobe of the broad ligament, blunt sharp combination to separate the surrounding adhesions, during the separation process the cyst ruptured and flowed out of the curry suggesting brown fluid of the uterus, cauliflower-like masses were seen in the cyst, sent for pathological examination: heterogeneous epithelioid cell masses were seen infiltrating the fibrous tissue of the left ovarian mass, some of which The pathological examination showed that the left ovarian mass was infiltrated with heterogeneous epithelial-like cell masses in the fibrous tissue and part of it was glandular and sieve-like, which was consistent with malignancy, and the possibility of clear cell carcinoma was considered. The patient was 46 years old, with the main cause of progressive dysmenorrhea aggravated for 10 years, and a pelvic mass was found for 1 day; the patient developed dysmenorrhea 10 years ago, with progressive aggravation and radiating pain in the lumbosacral region, which lasted for the whole menstrual period, slightly improved by hot compresses on the lower abdomen and oral analgesic drugs, with no significant changes in menstrual period, cycle and menstrual volume, and was consulted at the local hospital suggesting adenomyosis, without special treatment; the patient developed irregular menstruation 4 years ago, with the cycle The gynecological ultrasound showed that the myometrium of the anterior and posterior walls of the uterus was asymmetrical, the posterior wall was 5.6 cm thick, and the posterior wall was 6 cm thick with inhomogeneous echogenicity, suggesting adenomyosis and a possible chocolate cyst in the right ovary; conservative treatment was given, and the patient stopped taking the drug on her own after 2 injections, after which she stopped menstruating for 3 months. The right ovary was 4.2*3.6 cm cystic mass with poor cystic cavity transmission and solid part rich in blood supply; laparoscopic surgery was performed: the uterus was posteriorly positioned, irregular in shape, enlarged as in the second trimester of pregnancy, the posterior wall of the uterus was densely adherent to the intestinal canal, the right ovary was significantly enlarged and a 5 cm cystic mass was visible within it, densely adherent to the lateral wall of the uterus, the posterior lobe of the right broad ligament and the main sacral ligament; the adhesions were separated. During the process of separation of adhesions, the right ovary ruptured and flowed coffee-colored liquid with cauliflower-like mass inside, which was sent for rapid pathology: plasmacytoma was considered, and the possibility of germ cell tumor was not excluded; ovarian cancer staging surgery was performed, and the postoperative pathology was ovarian clear cell carcinoma with stage Ic G2; paclitaxel combined with carboplatin chemotherapy was given after surgery. The above two patients warned that clinical observation is not recommended for persistent ovarian masses, but active surgical treatment is needed to prevent the disease from occurring.