Prevalence and sonographic features of ectopic thyroidal thymus in children: A retrospective analysis.

Ectopic thyroidal thymic tissue is common in children. Radiologists should be vigilant about the unique US features of ectopic thyroidal thymus, including a hypo- and hyper-echoic echo pattern with multiple linear and punctate echoes, a fusiform shape, well-demarcated contours, and middle or low-lying location to differentiate it from other neck or thyroid lesions.