Mediastinoscopy is sometimes used as an aid in staging extent of disease when enlarged nodes are seen using imaging techniques. In these cases it is understood that all visible or gross tumor will not be removed. Obstruction of the catheter and possible seeding of the tumor into the abdominal cavity may be concerns. Pleural involvement chest wall invasion may also determined and recommendation as to the type of debulking procedure necessary can be made at this time. Fluid build up or pleural effusion is most often the first symptom which will prompt mesothelioma patients to seek medical attention. Often chemical pleurodesis aimed at relieving the accumulation of fluid in the intrapleural space can be accomplished during the same procedure.