Screening is testing for a disease like cancer in people without any symptoms. Thymus cancers are uncommon, and there are no widely recommended screening tests for them. Still, these cancers can sometimes be found early.
About 4 out of 10 people with thymomas have no symptoms when their tumor is found. In most of these cases the tumor is seen by chance on a test (like a chest x-ray or CT scan) that is done for some other reason.
Thymomas are often associated with symptoms that are not directly caused by the tumor mass itself. These are called paraneoplastic syndromes (tumor-related conditions). Some of these paraneoplastic syndromes, such as myasthenia gravis, red cell aplasia, and hypogammaglobulinemia, are described in How Is Thymus Cancer Diagnosed? These conditions can be very important in diagnosing some thymomas early because they may be present while the tumor is still at an early stage.