International Journal of Clinical & Medical Images

Clinical Image

A 2 months old infant is diagnosed to have unbalanced atrio-ventricular canal defect with Total anomalous pulmonary venous connection. Chest X-ray PA views showed a prominent convexity on the right border of the thymus and a straight inferior border, resembling a sail-like appearance. This is described as “Thymic sail sign” representing the triangular extension of the normal thymus in the right lateral border in chest radiographs (Figure 1). Cardiac computed tomography scan performed as a part of workup for the corrective surgery showed homogenous hypodense opacity (enlarged right lobe of the thymus) in the right side of the upper mediastinum (Figure 2). This sign is a normal finding in infants which should not be confused with the “spinnaker-sail sign” where the thymic lobe shadow is laterally and superiorly displaced due to pneumomediastinum. The thymic wave sign, a scalloped or wavy contour of the organ, is created by the impression of the anterior reflection of the ribs.