Primary tumors of the diaphragm are rare. The most common benign cystic lesions of the diaphragm are bronchogenic or mesothelial cysts, while the most common benign solid lesion is a lipoma. Benign tumors of the diaphragm are resected if they are symptomatic or if there is a doubt about the diagnosis. The most common primary malignant lesion is rhabdomyosarcoma. Malignant tumors are treated based on histology and often with chemotherapy and/or radiation along with surgical resection if feasible. Endometriosis, a benign process that metastasizes to the diaphragm, is typically treated medically; surgical ablation or resection is considered only after failed conservative treatment. Surgical resection of metastatic malignant tumors, such as ovarian cancer and thymoma, as well as malignancies affecting the diaphragm by direct extension, such as mesothelioma, lung, and esophageal cancer, may provide some survival advantage.
