The thymus is part of the body’s immune system and plays its largest role early in a person’s development. Thymectomy is the surgical removal of the thymus gland, which has been shown to play a role in the development of myasthenia gravis. Roughly 10 per cent of patients with myasthenia gravis have a thymoma or a tumour on the thymus gland. While most of these slow-growing tumours are benign, some may be cancerous (malignant).

Thymectomy is recommended for patients under the age of 60 years who have moderate to severe weakness from myasthenia gravis.