Anat Biol Anthropol.  2024 Mar;37(1):53-57. 10.11637/aba.2024.37.1.53.

Complex Variations of Double Pyramidal Lobe and Double Isthmus of the Thyroid Gland: A Case Report

• Hwang JW
• Lee DH
• Park E
• Park KR

• KMID: 2562478
• DOI: http://doi.org/10.11637/aba.2024.37.1.53

Abstract

The thyroid gland (TG) is an endocrine organ located at the level of the 5th cervical vertebra to 1st thoracic vertebra. The TG consists of right and left lobe, and the left lobe and the right lobe, and these two lobes are connected by the isthmus. The superior thyroid artery (STA) and the inferior thyroid artery (ITA) supply blood to the thyroid gland. We aimed to report complex variations of double thyroid lobes, double isthmus, and double pyramidal lobes to provide basic anatomical data for understanding clinical and pathological mechanisms. Thyroid variations were discovered while dissecting a cadaver at the College of Korean Medicine. In this case, the thyroid lobes, the isthmus, and the pyramidal lobes were formed independently on both sides. The thyroid lobes were divided into right thyroid lobe (RTL) and left thyroid lobe (LTL). The right pyramidal lobe (RPL) was connected from the superior border of the right isthmus (RIS) to the distal portion of the thyroglossal duct, and the left pyramidal lobe (LPL) was also connected from the superior border of the left isthmus (LIS) to the distal portion of the thyroglossal duct. The lengths of RTL, LTL, RIS, LIS, RPL, and LPL were 47.5 mm, 47.1 mm, 9.8 mm, 17.2 mm, 14.2 mm, and 20.3 mm, respectively. And the widths of RTL, LTL, RIS, LIS, RPL, and LPL were 17.0 mm, 13.9 mm, 6.0 mm, 11.3 mm, 4.8 mm, and 6.1 mm, respectively. The STA and the ITA was in a normal anatomical form, but the collateral circulation connecting the right and left sides did not exist. Since these variations may clinically lead to the possibility of incomplete thyroidectomy, clinicians need to understand the various variations of the TG and apply them to diagnosis and treatment.

Keyword

Thyroid gland; Double pyramidal lobe; Double isthmus; Anatomical variation