Fig. 19
CT is the imaging modality of choice for evaluating staging thymoma. Stage IVa thymoma (WHO type B3) in a 69-year-old woman. a, b Contrast-enhanced CT scan shows a well-circumscribed, flattened soft tissue lesion in the anterior mediastinum with calcification (arrow). Note the lobulated contour of the mass and the loss of the fat plane between the mass and the aorta. Pleural seeding is identified as an enhancing pleura-based nodule (open arrow). c Irregular border between the mediastinal mass and the lung parenchyma (arrowhead) is observed as a sign of locally advanced disease. Note the cellular bronchiolitis in the left lower lobe