Pyramidal Lobe of the Thyroid Gland: Surgical Anatomy in Patients Undergoing Total Thyroidectomy

Abstract

Background. Anatomic variations, the presence of the pyramidal lobe (PL), may impact completeness of thyroidectomy and effect of surgical treatment. Method. This study included 166 patients who underwent total thyroidectomy. The anterior cervical region between the thyroid isthmus and the hyoid bone was dissected during thyroid surgery. The incidence, size, and anatomical features of the PL were established in these patients. Results. The incidence of PL was 65.7%. No gender difference was found for PL incidence. The base of the PL was located at the isthmus in 52.3%, the left lobe in 29.4%, and the right lobe in 18.3% of patients. The mean length of the PL was 22.7 (range, 5–59) mm. The PL was longer than 30 mm in 23% of patients. One-third of the patients with short PL were men whereas women accounted for 80% of patients with long PL. Conclusions. The high incidence indicates that the PL is a common part of the thyroid. The PL generally originates from the isthmus near midline and is of variable length, extending from the isthmus up to the hyoid bone. Considering that the PL is a common structure, the prelaryngeal region should be dissected to achieve the completeness of thyroidectomy.

Anatomical Variations of Thyroid Glands in Northeastern-Thai Embalmed Cadavers

“…Thyroid gland abnormality was found in this research as a result of the emergence of pyramidal lobe (8.8 %). In the previous research conducted with different sample groups, with the diversities of the cadavers' nationalities and the places and the times of study, showed that the percentages of thyroid gland abnormality (18-66 %) were higher than the one found in this research (Braun et Begum et al;Joshi et al;Ozgur et al, 2011;Zivic et al, 2011;Park et al, 2012;Cengiz et al, 2013;Mortensen et al, 2014;Veerahanumaiah et al;Gurleyik et al, 2015;Rajkonwar & Kusre). In 2017, there was a reported case with pyramidal lobe emergence (Gurleyik et al) (Table III).…”

“…In another study, however, this abnormality was found at 21.6 % (Ranade et al). These thyroidal gland abnormality are susceptible to the operation of radiology physicians and surgeons in thyroidectomy and tracheostomy performances (Gurleyik et al;Sinos & Sakorafas, 2015;Kaklamanos et al, 2017). Being well acknowledge about the thyroidal anatomical change crucial step prior to giving treatment to the patients with thyroid gland abnormality (Rajkonwar & Kusre).…”

Separate thyrothymic thyroid remnant; clinically crucial anatomic variation

“…Notably, overlooked embryologic remnants may lead to recurrence. Considering the potential risk of recurrence from PL, its intraoperative identification and excision may decrease the risk of recurrence [6][7][8]. ZT should be excised after careful dissection on the posterior side of the gland considering the proximity of the tubercle to the recurrent laryngeal nerve [9].…”

Surgical anatomy of double pyramidal lobe on total thyroidectomy: a rare case report

“…The presence of this variation may encumber the completeness of total and subtotal thyroidectomy, which is usually the treatment of choice for benign and malignant diseases of the thyroid gland [3]. This is the first case of total thyroidectomy on a patient with DPL reported in Greece.…”