Intrathyroidal ectopic thymus in children: a sonographic survey

Abstract

Aims: Intrathyroidal ectopic thymus (IET) is being increasingly reported in the radiology literature. Most of the reports are of individual cases or small series and prevalence and natural course of the pathology is not well known. The purpose of this study is to establish the prevalence of IET in children and report long term follow-up results.Material and methods: In 180 children who were examined by ultrasound (US) for other reasons, 7 patients were indentified with IET. Together with the other seven children who were already under follow-up for IET (diagnosed using US criteria), these 14 patients were followed up with US for 30 months. Size, shape, location, echotexture and internal echoes of the lesions were evaluated.Results: There were 16 lesions in 14 children. The most common appearance was a fusiform hypoechoic lesion, with punctate and linear internal echoes and well-defined but slightly irregular borders located posteriorly in the lower thirds of the thyroid. In follow-up, there were no changes in echotexture, shape or border. In 3 patients, the lesion became slightly smaller, in a 10-year-old boy slightly larger, and in an 11-year old boy the lesion disappeared. In a patient with bilateral lesions, one lesion slightly decreased in size.Conclusions: IET in children may be more common than thought. Its growth reflects that of a normal thymus. Awareness of this entity is important in order not to misdiagnose them, especially as papillary cancer, and to prevent unnecessary interventions.

Ectopic cervical thymus in children: Clinical and radiographic features

“…). As providers have become more comfortable with identifying these lesions radiographically, there has been an evolution in management away from surgical biopsy or confirmation with MRI and needle aspiration to imaging surveillance alone …”

Pharyngeal Ectopic Thymus: A Case Report

“…6 Some researchers ascribe this difference to the different ages among the patients as ectopic thymus is thought to follow the same growth trend. 1,6 Rarely, as in this case, the newborn possesses an ectopic thymus with a length of about 40 mm. Most lesions are located on the left side with a slight male predominance.…”

“…The thymus is a specialized primary lymphoid organ of the immune system that contributes to the development of T cells. 1 Ectopic thymic tissue most frequently occurs in the submandibular triangle and lateral neck, accounting for 0.4% of neck masses. 2 Rare cases of oropharyngeal ectopic thymus have been reported in the literature.…”

Phantom Nodules Detected by Ultrasound Examination of the Neck: The Possibility of Ectopic Cervical Thymic Tissue in Adults

“…When the thymus has not fully descended into the mediastinum, thymic tissue can be found in the neck 7 8 9 . Several authors have described the US characteristics of ETT 7 8 9 10 11 12 13 14 15 16 17 . According to their reports, the lesions are well-defined, angular, solid nodules with multiple inner echogenic foci and linear structures.…”