Ultrasonographic Evaluation of the Pyramidal Lobe of the Thyroid Gland in Infants and Children in Western Turkey Between 2018 and 2020

The pyramidal lobe (PL) is a common anatomic variation of the thyroid gland with a reported prevalence of over 50% in adult series, but to the best of our knowledge, there are no data in the literature regarding its characteristics in the pediatric population.

The aim of this study was to evaluate the prevalence, anatomic, and morphological features of the PL in pediatric participants on thyroid ultrasonography (US).

The descriptive cross-sectional study design was used. Between November 2018 and January 2020, the US images obtained from 325 participants with normal thyroid glands were retrospectively evaluated. The presence, location, size, volume, the morphology of the base, and continuity or separation from the thyroid gland were noted for each PL.

The PL was present in 34.1% (110/325) of the pediatric participants. It was more frequent in girls than in boys. In all, 56.4% were found to originate from the left of the midline of the isthmus. One patient had double PL. The mean anteroposterior, transverse, and longitudinal diameters were 2.5 ± 1.4, 2.7 ± 1.3, and 5.6 ± 2.5 mm, respectively. The median volume of the PL was 15.11 mm3 . PL was longer in girls compared to boys; however, these changes were not significant (5.8 vs. 5.1, P = 0.406, respectively). A total of 63.6% of the PLs were with a wide base and narrow apex, and 36.4% were with a thin base size the same as the apex size. A separation of the PL from the thyroid was not observed.

The present study showed, for the first time, that the age of the children is positively correlated with the size and volume of the PL. The prevalence and location of the PL were consistent with those reported in the adult population.