title: The diagnostic dilemma of the posterior mediastinal thymus: CT manifestations.
abstract: Extension of the normal thymus into the posterior mediastinum is rare. The CT appearance of this anomaly in an infant is presented. A mass of soft-tissue density extended from the anterior mediastinum to the posterior chest wall. The absence of any tissue-cleavage plane in the lesion and a smooth continuous lateral margin are signs of posterior extension of the thymus, and they help to distinguish this from a normal anterior thymus being present with a posterior tumor.
mesh_terms: D003937:Diagnosis, Differential; D006801:Humans; D007223:Infant; D008297:Male; D008479:Mediastinal Neoplasms / Q000000981:diagnostic imaging*; D008482:Mediastinum; D013950:Thymus Gland / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed