Earlier, the term “peritoneal pseudomucinous tumor” was not a pathologic diagnosis, but only described a condition in which the patient had extensive jelly-like material in the peritoneum. However, the 2010 4th edition of the Classification of Tumors of the Digestive System includes peritoneal pseudomucinous tumor as a pathological diagnosis, which is equivalent to peritoneal mucinous carcinoma. The new edition of WHO considers all mucinous tumors that grow implantably in the peritoneal cavity to be carcinomas in nature. On this basis, they are divided into “low-grade mucinous tumors (carcinomas)” and high-grade mucinous tumors – i.e., mucinous carcinomas. Pseudomucinous tumors of the peritoneum are essentially diseases of the digestive system. When they do arise from the ovary, it is often a teratoma of the ovary with a large amount of intestinal-type mucinous epithelium, which can cause peritoneal pseudomucinous tumors. Because peritoneal pseudomucinous tumors frequently involve the ovaries, often bilaterally, and form metastases that are indistinguishable from primary mucinous (junctional) tumors of the ovaries, patients often present to obstetrics and gynecology for their initial consultation. The treatment plan in gynecology for peritoneal pseudomucinous tumors (low-grade mucinous tumors) is regular follow-up after surgery, with no further chemotherapy or radiation therapy. Chemotherapy is given only for peritoneal mucinous adenocarcinoma. Therefore, if the pathology department reports one: peritoneal pseudomucinous tumor (mucinous carcinoma of the peritoneum) according to the new version of WHO, the gynecology department will not know what to do. Therefore, I personally advocate to diagnose “peritoneal pseudomucinous tumor (low-grade mucinous tumor of peritoneum)” if it is low-grade (large amount of mucus, few epithelial cells, mild to moderate heterogeneity of epithelial cells), and directly report “high-grade mucinous carcinoma of peritoneum “. It is also necessary to communicate with gynecologists to make them realize that “low-grade mucinous tumor” is essentially a low-grade “mucinous adenocarcinoma”.