Abstract
Mucoepidermoid carcinoma (MEC) of the thymus is a rare malignant neoplasm of the anterior mediastinum. There are less than 30 cases described in the English literature. We report a case of a 47-year-old lady who presented with myasthenia gravis and was found to have a well-circumscribed anterior mediastinal mass in her medical work-up. This mass was surgically resected and subsequently found to be a primary MEC of the thymus. This is the first reported case of thymic MEC with concurrent myasthenia gravis. Her myasthenia symptoms have persisted following complete surgical resection of her tumour.