Dilek Sahin MD, Presenter: Nothing to Disclose

Ravza Yilmaz, Abstract Co-Author: Nothing to Disclose

Ayaz Agayev MD, Abstract Co-Author: Nothing to Disclose

Firdevs Bas, Abstract Co-Author: Nothing to Disclose

Emine Dilek Yilmazbayhan, Abstract Co-Author: Nothing to Disclose

Ensar Yekeler MD, Abstract Co-Author: Nothing to Disclose

The aim of this study was to reveal the characteristic sonographic features of intrathyroidal ectopic thymus, allowing specific diagnosis for this rare entity.

Between September 2008 and March 2010, 990 concequtive patients underwent thyroid US examination. Follow up ultrasound examination was performed in patients with intrathyroidal ectopic thymus suggested by ultrasound and Doppler ultrasound findings. These patients were followed in the period of 9 to 15 months. Two patients underwent fine needle aspiration biopsy because of the clinician’s demand.

Intrathyroidal thymus was found in 13 patients, one of them had bilateral lesions. Totally 14 intrathyroidal ectopic thymus were suggested according to the unique ultrasound and Doppler ultrasound features. None of the lesions had peripheral halo suggesting true thyroid nodule. One border of the lesions was abutting the medial or lateral thyroid gland counter in most of the cases (85%), the remaining were surrounded by the thyroid gland. Most of the lesions (78,5%) were not rounded in shape. Doppler US findings did not reveal perinodular flow signal or marked internal vascularity suggesting a true thyroid nodule. In all lesions, the intrathyroidal vessels passed through the lesions, without having any displacement. Follow up sonographic studies did not reveal any changes suggesting other thyroid pathologies.

Ectopic cervical thymus is not an uncommon entity. However, an aberrant thymic tissue located within the thyroid gland is not well-known. Intrathyroidal ectopic thymus has similar ultrasound and Doppler ultrasound features, not resembling other thyroid pathologies.

Awareness of typical ultrasound and Doppler ultrasound findings of intrathyroidal ectopic thymus will decrease false diagnoses and prevent unnecessary further procedures.

Sahin, D, Yilmaz, R, Agayev, A, Bas, F, Yilmazbayhan, E, Yekeler, E, Intrathyroidal Ectopic Thymus: Is Ultrasound Enough to Diagnose?.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9012662.html