Peritoneal mesothelioma is a tumor originating from the epithelial and mesothelial tissues of the peritoneum and is rarely seen clinically. Pathologically, they can be divided into adenomatous mesothelioma, cystic mesothelioma and malignant mesothelioma (PMM). The first two are benign tumors. The clinical presentation lacks specificity and may include abdominal pain, constipation, abdominal distention, weight loss and other manifestations of intestinal obstruction. Physical examination may reveal ascites or peritoneal masses. The ascites is exudate and some of it is bloody. It is easily misdiagnosed as tuberculous peritonitis, recurrent spontaneous peritonitis, inflammation of the mesentery or peritoneal metastatic cancer. A significant increase in ascites hyaluronic acid greater than 0.8 g/L is seen only in PMM. ascites exfoliative cell examination is also of some value, but the results are often difficult to determine. Elevated serum glycoconjugate antigen-125 (CA125) can help diagnose this disease. Clinical stage 1.Stage I. The tumor is confined to the peritoneum; 2.Stage II. The tumor invades the lymph nodes in the abdominal cavity; 3.Stage III. The tumor metastasizes to lymph nodes outside the abdominal cavity; 4.Stage IV. Distant hematogenous metastasis. Treatment 1.Surgical treatment Surgery is preferred for stage I and II PMM. The surgical procedure includes cytoreductive surgery to remove as much of the tumor tissue as possible. But in fact, due to the difficulty of surgery and diffuse lesions, it is difficult to achieve complete resection. For recurrence, re-operation is possible. For those who have intestinal obstruction, palliative surgery is feasible to relieve the obstructive symptoms. 2.Radiotherapy PMM is not sensitive to radiotherapy, and the effect of radiotherapy is not as good as that of pleural mesothelioma. However, for those who cannot completely remove the lesion by surgery or cannot be operated, radiotherapy is still an important therapy. The methods include external and/or internal irradiation. External irradiation generally uses 60Co or 186KV X-rays as the radiation source, and whole abdomen or local irradiation is chosen depending on the extent of the lesion. Chemotherapy 1. Cisplatin (DDP, cisplatin). Adults 80-120mg/m2 every 3 weeks, or 20mg/m2 for 5 days, every 3 weeks as a course of treatment, intravenous injection. Adverse effects include nephrotoxicity, ototoxicity, neurotoxicity, gastrointestinal reactions and bone marrow suppression. The addition of mannitol can reduce its accumulation in the renal tubules. 2.Carboplatin (CBP). Adults each time 300 ~ 400mg/m2, add 5% glucose solution or saline, dilute to a concentration of 0.5mg/ml solution, intravenous drip, repeat every 3-4 weeks or 100mg/d, add 5% glucose solution 500ml intravenous drip for 5 days; repeat once every 3-4 weeks. It can also be injected intraperitoneally with 300-500mg each time, once a week. 3.Bleomycin (BLM). Adults use 15-30mg, dissolved in appropriate amount of saline or 5% glucose solution for deep intramuscular injection, sedation or intravenous drip, twice a week; also can be changed to 1 time/d or several times a week according to the situation. Stey treated a patient with PMM with intraperitoneal injection of BLM, and the result was that the ascites disappeared and did not reappear after stopping the drug, and the patient survived for more than 3 years. However, high-dose intraperitoneal injection of BLM can cause pneumonia-like symptoms and even pulmonary fibrosis; in addition, fever and gastrointestinal reactions are more common, and individual patients have metamorphic reactions. 4.Paclitaxel. An anticancer drug extracted from the bark of the redbud tree, it inhibits mitosis and proliferation by inducing and promoting microtubule protein polymerization, preventing depolymerization and stabilizing microtubules. Paclitaxel also inhibited the regeneration of the microtubule network required for mitosis, hindered the formation of mitotic spindle leading to chromosome breakage, and inhibited tumor cell replication.