ESPE Abstracts

Objectives: to study the frequency, ultrasound characteristics and the evolution of intrathyroidal ectopia of thymus(IET) in children.

Materials and Methods: as part of an epidemiological study (2014-2017), an assessment consists of incidence of IET in pre-puberty children, which using ultrasound of 1164 patients (604 girls, 560 boys). As part of a clinical study (2014-2019), the ultrasound characteristics and the evolution of IET in pre-puberty children were counted. The follow-up period ranged 0.75-2.17 years, with an average of 1.57 ± 0.44 years. Ultrasound of the thyroid gland(TG) was made on the GE Healthcare LOGIQ P6 (USA) apparatus using a 9-15 MHz linear sensor.

Results: According to the results of an epidemiological study, focal thyroid pathology was diagnosed in 1.5% of patients(17/1164, 11 girls, 6 boys), which 1.3% had an IET(15/1164, P=0.0000, 10 girls, 5 boys, P=0.09), in 0.1%(1/1164, 1 girl) the node goiter, in 0.1%(1/1164, 1 boy) the diffuse nodular goiter. Age of patients with IET was 6.88 ± 0.36years. All cases, ultrasound of IET was similar with the characteristics of the correctly located thymus and was a focal formation localized inside the TG equally often in both (8/7, P=0.41) lobes closer to the lower departments, fusiform, with a wavy contour, without a capsule, hypoechoic structure with multiple small hyperechogenic inclusions, avascular, with a diameter 0.94 ±0.26cm. By diameter (0.9 ± 0.28cm VS 1 ± 0.23cm, P=0.5), location on the left (girl / boys: 5/3, P=0.26) and in the right lobes (girl / boys: 5/2, P=0.18) thymus ectopated into the TG tissue in children are equal. The follow-up of patients showed that IET persisted at the age of 7 years - in 73% (11/15) of cases, at the age of 8 years - in 7% (1/15) of cases (one boy from the group of frequently ill children). In this patient, thymus tissue ectopated into the TG decreased (by 1.8 times), but didn't completely disappear, while the initial diameter of focal formation (0.77cm vs 0.95 ± 0.26cm, P=0.53), age at the time of the last TG ultrasound (8.3years vs 8.46 ± 0.52years, P=0.65), observation period (2 vs 1.54 ± 0.44 years, P=0.17) didn't differ from those patients who had regressed IET.

Conclusions: In the structure of focal pathology of TG in children of pre-school age, IET takes the leading place. In the beginning of puberty period, IET can regress. Sonographic characteristics knowledge of IET allows ultrasound to optimize the management tactics of this children group.