Peritoneal benign mesothelioma

　　The etiology is related to asbestos exposure, and the onset interval is very long, often more than 30 years.

　　The close relationship between mesothelioma and asbestos exposure has been confirmed and recognized by an increasing number of facts. At the same time, European and American scholars have found that about 60% of patients with peritoneal mesothelioma have a history of occupational asbestos exposure or asbestos bodies in the lung tissue. In experiments using asbestos-induced animal pleural mesothelioma, a few animals also developed peritoneal mesothelioma, indicating that the occurrence of peritoneal mesothelioma is also related to asbestos exposure.

　　The pathogenic risk of different types of asbestos fibers is as follows: chrysotile > amphibole > crocidolite. It is generally believed that asbestos dust with a diameter of 0.5 to 50 μm first enters the respiratory tract, then passes through the diaphragmatic lymphoid tissue network or blood into the peritoneal cavity and deposits on the peritoneum, forming asbestos bodies. Sometimes, foreign giant cell reactions can occur around the asbestos bodies. Asbestos fibers ingested through the digestive tract can also reach the peritoneum through the intestinal wall. On average, it takes 35 to 40 years from exposure to asbestos to the discovery of mesothelioma, with the peak incidence occurring after 45 years of exposure. The exact mechanism by which asbestos causes mesothelioma is not yet fully understood. However, about 30% of mesothelioma patients have no history of asbestos exposure, and quantitative examination of asbestos fibers did not show signs of exposure to a large amount of asbestos fibers.

　　Other factors related to the occurrence of mesothelioma reported in literature include radiotherapy and a history of exposure to thorium dioxide (usually patients have a history of receiving related diagnostic examinations). In addition, patients with a history of Hodgkin's disease have an increased risk of developing mesothelioma.

　　Virus Infection: Simian virus 40 (SV40), a DNA tumor virus. According to literature reports, about 50% of the biopsy specimens of mesothelioma patients in the United States contain SV40, which induces telomerase activity in human primary mesothelial tumor cells but does not affect fibroblasts. The telomerase activity can be detected 72 hours after wild-type SV40 infection, and a clear DNA cloud ladder can be observed one week later. In the cell structure, the telomerase activity is proportional to the number of SV40 T antigens, and the telomerase activity of mesothelial cells infected with SV40 increases, making mesothelial cells less prone to apoptosis and more likely to form mesotheliomas.

　　Mesothelioma may also be related to factors such as exposure to fluorspar, tuberculous scars, chronic inflammatory stimulation, radioactive substances, genetic susceptibility, and others.

　　Common complications of benign peritoneal mesothelioma include pleural mesothelioma, gastrointestinal dysfunction, ascites, spontaneous hypoglycemia. Patients with advanced peritoneal mesothelioma may have systemic symptoms such as fatigue and weight loss. Some patients with large abdominal masses and a large amount of ascites may have symptoms of compression, such as difficulty breathing or dyspnea, lower limb edema, and difficulty urinating.

　　The main manifestations are abdominal pain, abdominal distension, ascites, abdominal mass, gastrointestinal symptoms, and systemic changes.

　　1. Abdominal Pain Abdominal pain is the most common symptom of peritoneal mesothelioma, presenting as persistent dull or bloating pain, which can also be intermittent severe pain or sudden severe pain. The pain is often located in the upper abdomen and right upper quadrant, and there are also reports of abdominal pain in the lower abdomen, leading to misdiagnosis as ectopic pregnancy or pelvic tumor in clinical practice. The occurrence of abdominal pain is related to the invasion of the parietal peritoneum, adhesion between the tumor and gastrointestinal and pelvic organs causing intestinal obstruction, organ torsion, and the presence of a large amount of ascites and abdominal mass, which produce displacement effects. The nature and location of abdominal pain may change during the course of the disease.

　　2. Abdominal Distension Due to factors such as ascites, abdominal masses, secondary dyspepsia, and intestinal obstruction, patients may have varying degrees of abdominal distension. Severe symptoms can affect eating and even cause difficulty breathing.

　　3. Ascites Approximately 90% of patients with peritoneal mesothelioma have ascites, and a considerable number of patients have rapid growth of ascites. Ascites can be yellow exudate or blood-sticky fluid, which is related to the active secretion of hyaluronic acid by tumor cells.

　　4. Abdominal Mass is one of the common clinical manifestations of peritoneal mesothelioma, and some patients seek medical attention due to abdominal mass. The abdominal mass of peritoneal mesothelioma can be solitary or multiple, with a texture that is slightly hard or hard, and a nodular surface. Masses located on the omentum or peritoneum of the mesentery can be moved during physical examination, and the mass may be tender. Masses located in the pelvis can be detected through rectal examination or bimanual examination. Patients with a large amount of ascites can have a clearer understanding of the condition of abdominal mass after draining and injecting ascites. Detailed physical examination can provide initial information about the location of the abdominal mass outside the abdominal wall and solid organs, thereby providing initial diagnostic data for clinical use.

　　5. Other symptoms may include loss of appetite, nausea, vomiting, diarrhea or constipation, urinary tract irritation, menstrual changes, fatigue, fever, weight loss, anemia. Some patients may have symptoms such as hypoglycemia and diffuse abdominal ossification. When patients have concurrent mesothelioma in other sites or peritoneal mesothelioma metastasis to other organs, or complications occur, corresponding clinical manifestations may appear.

　　Peritoneal mesothelioma originates from the epithelial and mesothelial tissues of the peritoneum, with asbestos dust as the pathogenic substance, and some viruses may also be the cause of mesothelioma. Actively preventing occupational diseases (such as textiles, construction) is the key to preventing this disease.

　　In making a diagnosis, in addition to relying on clinical manifestations, auxiliary examinations are also needed. The main examination methods include the following:

    1. Imaging examination.

　　2. Cytological examination of ascites cells.

　　3. Peritoneal biopsy, laparoscopy, laparotomy, and tissue collection for pathological examination can confirm the diagnosis.

　　Peritoneal mesothelioma dietary therapy:

　　Eating more alkaline foods can improve one's acidic constitution and at the same time supplement the necessary organic nutrients of the human body, so that the cancer cells can be starved while the body's immunity is restored.

　　Common acidic and alkaline foods:

　　1) Weakly acidic foods: white rice, peanuts, beer, wine, fried tofu, seaweed, clam, octopus, loach, etc.

　　2) Strongly acidic foods: egg yolks, cheese, white sugar desserts, persimmons, cuttlefish eggs, katsuobushi, etc.

　　3) Acidic foods: ham, bacon, chicken, tuna, pork, eel, beef, bread, wheat, butter, horse meat, etc.

　　1. Surgical treatment: For cases with stage I or II disease, surgery should still be the first choice or should be sought. The surgical methods include tumor resection and palliative resection. For patients with small tumors and limited lesions, the tumor and involved organs should be completely resected; if the lesions are extensive, efforts should be made to resect the main tumor (palliative resection). For patients with extensive and severe lesions, causing intestinal obstruction, and for whom surgery cannot be performed, palliative surgery can be considered to alleviate the patient's clinical symptoms. For benign and low-grade malignant peritoneal mesothelioma, surgical resection has a good efficacy, and reoperation can be performed if recurrence occurs. Zhu Weiqi and others reported a case of malignant peritoneal mesothelioma that underwent 5 resections within 20 years due to multiple recurrences. Literature reports that the median survival period of the best group of cases (7 cases) with the best therapeutic effect by simple surgical resection was 147.2 months. Therefore, surgery is still an effective treatment method for some cases of peritoneal mesothelioma.

　　Reducing the local recurrence rate of patients to 11.4% and the three-year survival rate to 66.7% shows that radiotherapy has a definite effect on peritoneal mesothelioma.

　　There have been many reports on the chemotherapy treatment of peritoneal mesothelioma. It is currently believed that peritoneal mesothelioma is moderately sensitive to chemotherapy, and commonly used drugs include: doxorubicin (ADM), cisplatin (DDP), vincristine (VCR), cyclophosphamide (CTX), bleomycin (BLM), and domestic anti-cancer new drugs such as youxiangrulose, among which doxorubicin has the most certain efficacy. Chemotherapy is divided into systemic chemotherapy and intraperitoneal chemotherapy.

　　(1) Systemic chemotherapy: After systemic administration of anticancer drugs, the distribution of drugs in the peritoneum is less. Foreign data show that the efficacy of systemic chemotherapy is only 11% to 14% regardless of single-agent or combination therapy. The combination chemotherapy regimens include: DDP+ADM; DDP+CTX+VCR; CTX+VCR+BLM, etc., but many scholars have proposed that combination chemotherapy does not necessarily improve efficacy.

　　(2) Intraperitoneal chemotherapy: In recent years, it has been considered that intraperitoneal injection of medication can increase the local concentration of drugs and reduce the adverse reactions of doxorubicin. Intraperitoneal chemotherapy can not only eliminate residual tumor tissue after surgery, reduce recurrence, but also make the tumors of some patients who have lost the opportunity for surgery shrink, reduce ascites, and effectively control the condition. The dose of intraperitoneal medication is similar to or slightly higher than that of intravenous administration, and it is repeated after 1 week, and can be continuously injected for several weeks according to the condition. Ito administered DDP intraperitoneally to a patient whose tumor could not be removed by surgery, and combined it with uracil and tegafur. After 223 days, the patient had no abdominal mass and the ascites completely disappeared. However, the pelvic mass recurred after 8 months, and DDP and camptothecin were re-administered, but the effect was not good. Ma et al. used continuous hyperthermic peritoneal perfusion (CHPP) combined with DDP local injection to treat primary peritoneal mesothelioma, and there were no obvious local adverse reactions during the treatment. All patients could tolerate CHPP, and follow-up for 10 months showed that no patient died due to CHPP treatment.

　　3. Radiotherapy: Radiotherapy includes external and internal irradiation, and can use 60Co or 186 kV X-ray as the radiation source. It is suitable for cases where surgery is not thorough or cannot be performed, and the full abdominal or local irradiation can be determined according to the extent of the lesion. It is generally believed that the efficacy of radiotherapy for peritoneal mesothelioma is not as good as that for pleural mesothelioma, which may be related to the higher dose of radiotherapy used for pleural mesothelioma. Data from Shanghai Medical University's Cancer Hospital shows that full abdominal irradiation with a dose of 2400cGy every 6 to 7 weeks can reduce the local recurrence rate to 11.4%, and the 3-year survival rate to 66.7%, indicating that radiotherapy is effective for peritoneal mesothelioma.