Abstract
Ectopic thymoma is a rare tumor that arises from the abnormal migration of thymus tissue. They are extremely rare and have a broad spectrum of clinical symptoms. Therefore, preoperative diagnosis is complex and can be easily misdiagnosed. Complete resection is the treatment of choice to avoid recurrence, radiotherapy and enhanced survival. Regretfully, many patients arrive at a late stage, limiting our therapeutic options; therefore, pre-operative diagnosis is vital. We present the case of an otherwise healthy 32-year-old woman; after a chest X-ray was done for a routine medical evaluation, a mass was discovered in her mediastinum. After surgery, a B2 thymoma attached to the pericardium was discovered and successfully treated.