Chocolate cysts over 10 centimeters are not necessarily cancerous. Strictly speaking, the criteria for chocolate cysts to be cancerous are not only the size of the cyst. Chocolate cysts over 10 centimeters usually refer to type II-C chocolate cysts, which have obvious infiltration or multiple cystic cavities within the cysts with large size, which are not easy to be peeled off, and are difficult to be treated by surgery, easy to recur, and have a certain chance of becoming cancerous. However, the cancer of chocolate cysts is not based on the size of the cysts. Many cysts are relatively small and can recur, and these cysts will also have the chance of cancer, such as ovarian endometrioid cancer and clear cell carcinoma. Chocolate cysts over 10 centimeters are already relatively large and can be treated by surgery. For those who have fertility requirements, they can undergo fertility preservation and ovarian function preservation surgery; for those who do not have fertility requirements and have a high chance of malignant transformation, they can undergo radical surgery, and active treatment can reduce the chance of cancer transformation. If you have any other questions, please consult a professional doctor for guidance.