Myasthenia gravis (MG) is an autoimmune disease in which antibodies attack receptors at the neuromuscular junction, causing muscle weakness that typically improves with rest and worsens with activity. Approximately 10 to 15 percent of myasthenia gravis patients have a thymoma, a tumor of the thymus gland, while additional patients have thymic hyperplasia. On thyroid ultrasound, the anterior mediastinum can sometimes be evaluated for the presence of thymic masses or abnormalities. CT or MRI of the chest provides superior evaluation of the mediastinum and thymus for cases of suspected thymoma, but ultrasound may be an initial screening tool.
Sonography Term