Approximately 30{ca68fe27842bfe4db706c0c793b2b6cfc22209afc6687532f180b9461a4d4599} of patients with thymoma or thymic carcinoma have no symptoms when the tumor is diagnosed. These are typically detected when doctors are looking for other things, during routine chest x-rays, for example. Possible symptoms are listed in table 1.

Persistent coughing
Chest pain
Upper airway congestion
Muscle weakness*
Shortness of breath
Arm or facial swelling
Difficulty swallowing*
Anemia (low red blood cell count)
Increased risk of infection

Table 1. Possible symptoms of thymic epithelial tumors

* these symptoms may be related to myasthenia gravis (meaning severe muscle weakness) which may be the presenting sign of thymoma