The role of PET/CT in the management of peritoneal mesothelioma

Learning Objectives To describe the pathogenesis and management of peritoneal mesothelioma (PM) and the role of PET/CT in the management of PM.

PM is a rare form of cancer that develops from either the parietal or visceral peritoneum. The pathogenesis of PM remains unresolved, however, it has been proposed that asbestos fibers from the lung are transported to the abdomen and associated organs via the recruitment of lymphatic system. Additionally, asbestos fibers may be deposited in the gut after ingestion of sputum contaminated with asbestos fibers. The accumulated asbestos acts as a complete carcinogen with the development of PM via direct physical interactions with the cells of the mesothelium in conjunction with indirect effects following interaction with inflammatory cells. PM has also been associated with irradiation, intrapleural thorium dioxide, and inhalation of other fibrous silicates and simian virus 40. PM does not usually cause symptoms until the disease is advanced. PM also very fast growing. The late diagnosis and rapid growth rate combine to make PM a very deadly disease. The patient is treated with the combination of chemo-radiation and surgery. Diagnosis of PM is often made by analyzing tumor markers (e.g. serum mesothelin-related protein), imaging studies and histopathology. The extent of the primary and metastatic lesion is best assessed with CT. However, it is not possible to make a definitive diagnosis by CT alone. CT may help focus the possible causes for symptoms, rule out others and guide a future biopsy. The only way to make an accurate, definitive diagnosis of PM is to obtain and analyze a direct biopsy of the tissue by immunohistochemical and other specialized means, but it requires that the patient undergo a surgical procedure. Hybrid PET/CT can be used to assess the primary lesion, detect metastasis, evaluate treatment response and restage after therapies, but its clinical role has not been well established. Cases represented illustrate the use of PET/CT in the management of this disorder