Sonographic findings in ectopic cervical thymus in an infant

Abstract

We present the case of a 28-day-old boy with ectopic thymic tissue in the neck. Sonography showed a well-delineated, homogeneous lesion in the left submandibular region that was isoechoic relative to the mediastinal thymus. The lesion had angular margins and lacked a mass effect despite its large size (3 x 2 cm). On power Doppler imaging, arteries with an intermediate-impedance flow pattern were seen entering the lesion from the inferior and lateral margins. On both T1- and T2-weighted MR images, the lesion was isointense relative to the mediastinal thymus and had higher and lower signal intensity than muscle and fat, respectively. A sonographically guided needle biopsy confirmed the diagnosis of ectopic thymus.

Sonographic appearance of intrathyroid ectopic thymus in children

“…7 Ultrasonography (US) is the modality of choice for evaluating intrathyroid ectopic thymus in children as it is noninvasive and does not involve radiation exposure. The US appearance of ectopic thymus is similar to that of normal thymus 9,10 ; however, the specific location of intrathyroid ectopic thymus has not been reported in the literature. The purpose of our study is to describe the US appearances of intrathyroid ectopic thymus in children focusing on the location inside the thyroid.…”

“…9,10 Furthermore, as intrathyroid ectopic thymus seems to be more common than previously thought, knowledge of specific US findings of the lesion has become increasingly important. 25 Previous reports described intrathyroid ectopic thymus as a well-defined hypoechoic nodule with linear and dot-like echoes.…”

Ectopic intrathyroidal thymus misdiagnosed as a thyroid nodule: Sonographic appearance

“…8,9,21 The Doppler patterns of normal thymic tissue have been described in 2 cases of aberrant cervical thymus, but without a confident differential diagnosis. 22,23 Further investigation, including additional imaging and/or needle biopsy, is rarely indicated unless the mass presents with a suspicious appearance.…”

Ectopic cervical thymus as a rare cause of pediatric neck mass: the role of ultrasound and MRI in the diagnosis. Case report.

“…Familiarity with the ultrasound appearance is useful in the diagnosis of ECT and preventing unnecessary surgeries [6,7]. Sonographic appearance of the normal thymus is described as a well defined homogenous, hypoechoic mass with multiple echogenic structures and internal echogenicities [8][9][10][11][12][13]. In an ultrasound-pathology correlation study of intrathyroid anatomy, the echogenic linear structures within the thymus represent connective tissue septa and blood vessels in the septa [9].…”