A number of masses arise in relation to the thymus. The radiologist has an important role regarding the differential diagnosis between non-tumoral thymic pathology and malignant thymic tumors. In general, a benign hyperplasia of the thymus occurs in children and young adults, while in adults the thymoma is the most common tumor. Furthermore imaging is of great importance in the preoperative staging and oncological follow-up. To evaluate the thymus CT scan is used in the majority of the cases. MRI or PET-CT can have an added value in the differential diagnosis of various thymic pathologies in some cases. We present an overview of thymic masses with typically imaging features: thymic hyperplasia, thymomas, thymic carcinoma, thymic non-hodgkin lymphoma, thymolipoma and thymic carcinoid.