Radiology of Normal Thymus, Thymic Lesions, and Tumors

Abstract

Thymus is an anterior mediastinal lymphoid organ with an important role in innate immunity. The size of thymus varies with age and a normal thymus in infancy may be mistaken as pathological. Typical imaging characteristics on radiograph, ultrasonography, CT, and MRI may add useful clues in differentiating a normal thymus from a disease process. The disorders affecting thymus are also diverse. Some of the thymic lesions may have prominent systemic manifestations. This chapter describes the imaging characteristics of normal thymus and various thymic pathologies (congenital, benign, and malignant neoplasms).