Cystic mesothelioma is a rare and benign form of mesothelioma that develops on the peritoneum. The peritoneum is the thin membrane that lines the abdominal wall and surrounds the organs of the abdomen. This mesothelioma produces cysts within the abdominal cavity. Surgery to remove the cysts usually is effective in treating the symptoms. However, patients experience a high recurrence of cyst development. Although not cancer, this form of mesothelioma is a serious illness requiring long term monitoring and treatment. The diagnosis presents difficulties and requires extensive laboratory analysis and immunohistochemical studies. Normal life expectancy is usual. In some cases treatment may be given to relieve pain. Young women are the population most often diagnosed with the disease cystic mesothelioma.