Zeynep Nilüfer TEKİN
Ectopic thymic tissue is a benign lesion presented in children and generally requires no treatment. Only half or less of the thymus is located in the chest and the latter as ectopic neck mass, in patients with an undescended thymus. The level of thyroid is the most common site for ectopic thymus, which may be due to the close relationship of the descent of the two organs. However, ectopic cervical thymus is a rare normal variant mimicking neck mass and usually detected incidentally. 9 year old girl with a palpable left cervical lump presented to the pediatric department of hospital. On physical examination, nontenderness mildly firm mass was detected by palpation. Laboratory findings were normal. The patient was referred to radiology department for neck ultrasound (US). Ectopic cervical thymus in addition to intrathyroidal thymic tissue was defined in US imaging. In detail, intrathyroidal thymic tissue and ectopic cervical thymus were seen as an angular shaped solid lesions with multiple focal nonshadowing echogenities similar to sonographic appearances of normally located thymus. Sonographic findings are generally sufficient for the accurate diagnosis. This case emphasizes that radiologists should be aware of the presence of intrathyroidal thymus and cervical ectopic thymus as a normal variant to avoid concerning as if a primary thyroid neoplasia or other thyroid nodules, due to the their different treatment approaches. So that, it should be possible to avoid unnecessary surgery in these patient group.

Anahtar Kelimeler: Intrathyroidal thymus, ectopic cervical thymus, neck, ultrasonography, children