My mum has been diagnosed with a thymoma about 5,8 by 6,5 cm. Suffers fm severe left shoulder pain and is under high blood pressure medication. What is the best way to proceed with this thymoma, is it malignant and what is the survival rate of patients with thymoma. She is 62 years old. Lastly what causes this type of growth.

Summarized question: What causes thymoma?