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Illustration of the classi- Wcation of the thyroid gland shapes. 1 A pyramidal lobe (P) extending from the left side and crossing over the right side (type 1). 2 A horseshoe-shaped gland without a P (type 2). 3 A gland with two separate lobes: levator glandulae thyroideae extends from the hyoid bone and bifurcates caudally to get attached to the fascia of each lobe (type 3). 4 A horseshoe-shaped gland with a P extending to the thyrohyoid membrane on the right (type 4). 5 A horseshoeshaped gland with a P extending to the thyrohyoid membrane on the left (type 5). 6 A horseshoeshaped gland with a P extending to the thyrohyoid membrane in the middle (type 6) 7 The type in which inferior thyroid artery divides the gland into lobes (type 7). 8 A horseshoe-shaped gland with a P by LG extending to the hyoid bone (type 8). 9 Two separate lobes each extending as Ps (type 9). 10 Two PYR-Ls united cranially (type 10). 11 Two separate lobes each with two Ps extending to the hyoid bone (type 11). 12 A thyroid gland with two separate lateral lobes (type 12). R right lobe, L Left lobe, I isthmus, P pyramidal lobe, LG levator glandulae thyroidea , A inferior thyroid artery, arrow separation
Source publication
Variation in the descent of the thyroid gland and during fetal life and regression of the thyroglossal duct is associated with many variations in form of the mature gland. The shape and morphometric details of gland, its extension as the pyramidal lobe (PYR-L) and attachments of the levator glandulae thyroidea were studied in 40 cadavers. We catego...
Citations
... Thousand five hundred and forty-three articles were screened, and 156 were subjected to a full-text evaluation. Finally, 24 studies reached the criteria and were included in the present meta-analysis (Akudu et al., 2018;Al-Azzawi & Takahashi, 2021;Ayandipo et al., 2018;Braun et al., 2007;Cengiz et al., 2013;Dessie, 2018;Freilinger et al., 2022;Gurleyik et al., 2015;Harjeet et al., 2004;Irawati et al., 2016;Kim et al., 2013Kim et al., , 2015Kim, Ha, et al., 2014;Léger et al., 2002;Mangalgiri et al., 2018;Mortensen et al., 2014;Ozgur et al., 2011;Park et al., 2012;Prakash et al., 2012;Ryu et al., 2014;Savage et al., 1984;Sawicka-Gutaj et al., 2014;Siraj et al., 1989). To minimize potential bias and maintain an accurate statistical methodology, articles such as case reports, case series, conference reports, reviews, letters to the editor, and studies that provided incomplete or irrelevant data were excluded. ...
... Data about the morphometric properties of the PL have also been presented by studies in the past. The mean length of the PL has been reported to be between 16.13 and 26.5 mm (Ozgur et al., 2011;Ryu et al., 2014). However, the most studies concerning this topic, report a mean length higher than 22.00 mm (Braun et al., 2007;Gurleyik et al., 2015;Ryu et al., 2014). ...
The pyramidal lobe (PL), also known as the third lobe of the thyroid gland or lobe of Lalouette is an embryological remnant of the caudal end of the thyroglossal tract. The following meta-analysis aims to provide a detailed analysis of the anatomical variations of the PL using the available data in the literature. Major online medical databases such as PubMed, Scopus, Embase, Web of Science, Cochrane Library, and Google Scholar were searched in order to find all studies considering the prevalence and anatomy of the PL of the thyroid gland. Finally, a total of 24 studies that met the required criteria and contained complete and relevant data were included in the present meta-analysis. The pooled prevalence of the PL was found to be 42.82% (95% CI: 35.90%-49.89%). An analysis showed that the mean length was 23.09 mm (SE: 0.56). The mean width was found to be 10.59 mm (SE: 0.77). The pooled prevalence of the PL originating from the left lobe (LL) was established at 40.10% (95% CI: 28.83%-51.92%). In conclusion, we believe that this is the most accurate and up-to-date study regarding the complete surgical anatomy of the PL. The PL was prevalent in 42.82% of the cases, being slightly more prevalent in males (40.35%) than females (37.43%). The mean length and width of the PL were 23.09 mm and 10.59 mm, respectively. Our results should be taken into consideration when performing procedures on the thyroid gland, such as thyroidectomies. The presence of the PL can affect the completeness of this procedure and lead to postoperative complications.
... The author added that ductal degeneration defects can lead to the formation of a pyramidal lobe that may be connected to the hyoid bone by levator glandulae thyroideae (Figures 2 and 3). Variations of the thyroid gland [7,[9][10][11][12]. The high incidence of the pyramidal lobe has made the structure be appreciated as normal, and therefore its likelihood ought not to be discounted during preoperative diagnosis of patients [10]. ...
Objective The pyramidal lobe is an auxiliary lobe of the thyroid gland obliviously overlooked by students during routine dissection and sometimes undermined by surgeons, physicians, radiologists, and endocrinologists during management of thyroid related disorders. Pyramidal lobe is a keen organ to investigate within the visceral compartment of the neck and its significance ought to be emphasized during exploration and resection of this structure in primary thyroid operations. Method: Dissimilarity was encountered during routine cadaveric dissections, overlying neck muscles were exposed, and the tissue was examined. Results: The macroscopic assessment revealed a capsulated glandular tissue with three lobes. Pyramidal lobe was located deep to the strap muscles of the neck at the midline below the Adam's apple. Conclusion: Pyramidal lobe is considered a normal component of the thyroid gland with variable morphology and position. Its removal during surgery of the thyroid to treat non-malignant disease cases has proven to significantly reduce chances of cancer recurrence.
... The pyramidal lobe (PL) is an accessory lobe of the thyroid gland, consisting of thyroid tissue that remains at the caudal end of the obliterated thyroglossal duct. Its varying prevalence in previous studies ranged from 35.7 to 60.0% in cadaver studies [1][2][3][4][5] and from 12.3 to 61.0% in surgical studies [6][7][8][9][10], as showcased in Table 1. ...
... A fibrous or muscular band descending from the hyoid bone to the tip of the PL, also referred to as levator glandulae thyroideae muscle was described in 17.5-49.5%. It is believed to be a remainder of the thyroglossal duct and is of yet unknown clinical significance [2,3,5]. ...
... -Caudal: Thyroid isthmus. [2] 58.1% (61/105) Ozgur et al. [3] 60.0% (24/40) Prakash et al. [4] 35.7% (25/70) Milojevic et al. [5] 55.2% (32/58) Surgery-based studies Geraci et al. [6] 12.3% (74/604) Zivic et al. [7] 61.0% (61/100) Kim et al. [8] 59.8% (79/132) Ryu et al. [9] 60.0% (81/135) Irawati et al. [10] 36.9% (38/103) -Cranial: Approximately 1 cm cranial of the thyroid isthmus. -Lateral: lateral border of the infrahyoidal muscles. ...
Purpose
The pyramidal lobe (PL) is an ancillary lobe of the thyroid gland that can be affected by the same pathologies as the rest of the gland. We aimed to assess the diagnostic performance of high-resolution sonography in the detection of the PL with verification by dissection and histological examination.
Methods
In a prospective, cross-sectional mono-center study, 50 fresh, non-embalmed cadavers were included. Blinded ultrasound examination was performed to detect the PL by two investigators of different experience levels. If the PL was detected with ultrasound, dissection was performed to expose the PL and obtain a tissue sample. When no PL was detected with ultrasound, a tissue block of the anterior cervical region was excised. An endocrine pathologist microscopically examined all tissue samples and tissue blocks for the presence of thyroid parenchyma.
Results
The prevalence of the PL was 80% [40/50; 95% CI (68.9%; 91.1%)]. Diagnostic performance for both examiners was: sensitivity (85.0%; 42.5%), specificity (50.0%; 60.0%), positive predictive value (87.2%; 81.0%), negative predictive value (45.5%; 21.0%) and accuracy (78.0%; 46.0%). Regression analysis demonstrated that neither thyroid parenchyma echogenicity, thyroid gland volume, age nor body size proved to be covariates in the accurate detection of a PL ( p > .05).
Conclusion
We report that high-resolution ultrasound is an adequate examination modality to detect the PL. Our findings indicate a higher prevalence than previously reported. Therefore, the PL may be regarded as a regular part of the thyroid gland. We also advocate a dedicated assessment of the PL in routine thyroid ultrasound.
... This finding conforms to the previous work reported by Mortensen et al. (5), who also found one patient with two PLs on thyroid US. The bilaterality rate of the PL in sonographic studies was lower than those in previous reports obtained on cadavers, ranging from 3.3 to 10% (18)(19)(20). The low bilaterality rate of the PL on US might be explained by the limitation in sonographic detection for thin PLs. ...
Background: 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. Objectives: The aim of this study was to evaluate the prevalence, anatomic, and morphological features of the PL in pediatric participants on thyroid ultrasonography (US). Methods: 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. Results: 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. Conclusion: 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.
... The thyroid gland is one of the largest endocrine glands in the human body and resides in the lower neck, anterolaterally to the trachea and larynx. It is composed of a left and a right lobe interconnected by an isthmus (Ozgur et al., 2011;Policeni et al., 2012). Blood supply to the thyroid gland is provided by two pairs of inferior and superior thyroid arteries that branch from the thyrocervical arteries and the external carotid arteries, respectively (Loevner, 1996). ...
The endocrine system consists of several highly vascularized glands that produce and secrete hormones to maintain body homeostasis and regulate a range of bodily functions and processes, including growth, metabolism and development. The dense and highly vascularized capillary network functions as the main transport system for hormones and regulatory factors to enable efficient endocrine function. The specialized capillary types provide the microenvironments to support stem and progenitor cells, by regulating their survival, maintenance and differentiation. Moreover, the vasculature interacts with endocrine cells supporting their endocrine function. However, the structure and niche function of vasculature in endocrine tissues remain poorly understood. Aging and endocrine disorders are associated with vascular perturbations. Understanding the cellular and molecular cues driving the disease, and age-related vascular perturbations hold potential to manage or even treat endocrine disorders and comorbidities associated with aging. This review aims to describe the structure and niche functions of the vasculature in various endocrine glands and define the vascular changes in aging and endocrine disorders.
... The first two types of the muscle are associated with the pyramidal lobe of the thyroid gland. The incidence of the levator glandulae thyroideae muscle as reported in the literature ranges widely from 0.5% to 49.5% of cases [10][11][12][13], and the structure of this muscle is described as fibrous [13,14], fibroglandular [15], fibromuscular [13], fibromusculoglandular [16] or muscular [7,17]. ...
... The first two types of the muscle are associated with the pyramidal lobe of the thyroid gland. The incidence of the levator glandulae thyroideae muscle as reported in the literature ranges widely from 0.5% to 49.5% of cases [10][11][12][13], and the structure of this muscle is described as fibrous [13,14], fibroglandular [15], fibromuscular [13], fibromusculoglandular [16] or muscular [7,17]. ...
... The first two types of the muscle are associated with the pyramidal lobe of the thyroid gland. The incidence of the levator glandulae thyroideae muscle as reported in the literature ranges widely from 0.5% to 49.5% of cases [10][11][12][13], and the structure of this muscle is described as fibrous [13,14], fibroglandular [15], fibromuscular [13], fibromusculoglandular [16] or muscular [7,17]. ...
We investigated two structures that are in close association with the pyramidal lobe of the thyroid gland. Our investigation was performed using microdissection and histological examination in 106 human postmortem specimens. The first investigated structure was identified as the thyroid fibrous band that was present in 28.3% of cases. This band was always associated with the pyramidal lobe (which was significantly longer and thicker when associated with this band) and it had a constant hyopyramidal extension; it was located close to the midsagittal plane and predominantly composed of dense irregular connective tissue. The second investigated structure was the levator glandulae thyroideae muscle, which was associated with the pyramidal lobe in only 13.6% of cases. This muscle had a double extension, hyo-pyramidal and laryngo-pyramidal it was located farther from the midsagittal plane, it was longer and thinner than the thyroid fibrous band and predominantly composed of striated muscle fibers. We confirmed our hypothesis that the thyroid fibrous band, which may be considered as the partial fibrous remnant of the thyroglossal duct and levator glandulae thyroideae, and which may be considered as infrahyoid or laryngeal muscle, are two different structures of the thyroid gland.
... Thyroid gland is highly vascular butterfly shaped and placed anteriorly in the lower part of the neck consisting of two symmetrical lateral lobes connected by a midline isthmus [1]. The gland is composed of right and left lobes, typically interconnected by an isthmus in the midline, lying anterolateral to the larynx and trachea at approximately the level of the second and third tracheal rings [2]. The normal thyroid gland weighs approximately 30 g. ...
... [23], and absent in females in his study, all the above authors have reported a little lower value compared to us. In our study PL on left side was seen in 19 cases (38%) and more prevalent in males-15 cases 41.7%,females-4 cases 28.6%, the same was reported by authors like Sreekanth et al [24], Milojevic B et al [21],Oya sagiroglu.A [9], Zuhal Ozgur et al [5] and Veena kulkarni et al [2]. ...
... These hormones are directly associated with bodymetabolism and playa vital role in brain maturation during fetal development [1]. This endocrinegland consists ofright andleft lobes, usually interconnected by an isthmus within the sheet, lying anterolateral to the voice box and trachea at the level of the second and third cartilaginous tube rings [2]. ...
Background:
Serum electrolytes, Creatinine, and thyroid profile play an important role in I131 treated patients of thyroid disorders.
Objectives:
To determine the effect of radioactive iodine (I131) on renal parameters, serum electrolytes and the correlation among TFT'S, creatinine, and chloride levels before and after I131 treatment in thyroid disorders.
Methods:
The study was performed on 55 patients of thyrotoxicosis with age ranging from 16-65 years (mean age= 41±14years and BMI=24.8±4.46). The significance of the differences between the results of 1st, 2nd, and 3rd-time serum analysis was assessed by paired Student's t-test. Association between parameters was assessed by Spearman correlation analysis.
Results:
40 patients were taking Carbimazole, and 15 were directly recommended for I131 therapy. Strongly significant variations were observed for TFT'S (T3=0.012, T4 =0.017, and TSH=0. 001) during follow-up treatment. Before taking I131 (Serum analyzed at 1st time), there observed negative correlation of T3(r=-.46, p=0. 002) and TSH (r=-0.31, p=0.02) with creatinine, and positive correlation of TSH(r=0.29,p=0.02) with chloride. BMI was negatively correlated with potassium(r=-0.30, p=0.02). At the 2nd time (after stopping the Carbimazole), no correlation results were observed. Two months after oral administration of I131, creatinine, and chloride level was significantly increased (p=0.000), (P=0. 03) respectively, but had no correlation with TFT'S.
Conclusion:
Our findings suggest that patients with goiter (diffused or toxic) have association of TFT'S and BMI with serum electrolytes and creatinine , I131 therapy is also associated with the increase in creatinine and chloride levels of patients leading to kidney problems.
... [14] The anatomical neighborhood of the gland to the inferior thyroid artery and laryngeal nerve is important for complications that may occur during thyroid surgery. [15,16] ...
