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The thyroid gland is prone to variations due to its embryological origin and descent. These variations can cause distortion of its morphology and have been associated with thyroid disorders. This study aimed to provide evidence-based data on the morphological variations of the thyroid gland. In this study, the morphological variations of the thyroid gland pertained to the presence or absence of pyramidal lobe (PL), levator glandulae thyroidae (LGT) and isthmus. The main objective of this study was to assess the morphological variations of the thyroid gland and its relationship to the recurrent laryngeal nerve\r\cadavers. This was a cross-sectional descriptive study, conducted at the Pathology Department of the University Teaching Hospitals (UTH) in Lusaka, Zambia. In the study there were 46 cadavers; 36 males and 10 females aged between 20-64. The study involved dissection and removal of the hyoid bone, larynx, trachea, oesophagus, and thyroid gland en bloc. The thyroid gland was observed for the presence of the PL and LGT, and absence of isthmus. If present, the length, width and height were measured using a Vernier caliper. Location of the isthmus as well as the relationship of the thyroid gland to the recurrent laryngeal nerves (RLNs) were also observed. The most common variation was presence of PL, 32.61% (36% of males and 20% of females). The most common origin of the PL was both the isthmus (W/o) and left lobe (40%). Levator glandulae thyroideae were commonly attached to the hyoid bone (72.7%). Statistically significant differences (<0.0001) were found in the mean length of LGTbetween males and females. Thickness of the PL was more in females than males and this difference was significant (< 0.015). The majority of the isthmi were found located on tracheal rings 1 and 2 (32.6%). The RLNs were mostly medial to the thyroid gland; LRLN (93.5%) and RRLN (91.3%). There was a high incidence of RLNs traversing the larynx posterior to the cricothyroid joint, 89.1% of LRLNarxd 93.5% of the RRLN. Knowledge of these variations, their measurements and the relationship of the thyroid gland to the RLNs may be of help to surgeons to perform safe and effective thyroid surgeries with reduced complications. [ABSTRACT FROM AUTHOR]

Background: The size of thyroid gland is subject to great variations. The thyroid gland consists of two lobes and a bridging isthmus. It is located anteriorly in the neck at the level of the C5–T1 vertebrae deep to the Infrahyoid muscles. The developmental anomalies of the thyroid gland are partial and total agenesis, various ectopic tissues, accessory thyroid, and absence of isthmus. This distorts the morphology of the gland and causes clinical and functional disorders. Methods: The thyroid gland was removed from 28 embalmed cadavers. Specimen of abnormal conditions like enlarged gland, partial and total agenesis of gland and absent isthmus was excluded from the study. Presence of pyramidal lobe and levator glandulae thyroidea was noted. The dimensions of each lobe was measured using Vernier caliper. Descriptive statistics was calculated as mean and standard deviation. Results: The average length (right lobe=4.96cm, left lobe= 4.48cm), width (right lobe=2.25cm, left lobe=1.86cm) and thickness (right lobe=1.53cm, left lobe=1.45cm) were measured. Pyramidal lobe was present in 32.14%. Levator glandulae thyroidea was found in only one case (3.57%). Conclusion: Variation in the dimensions of thyroid gland are reported. Knowledge of the wide ranging variations and measurements will help the surgeons and radiologists in correct interpretation, diagnosis and treatment of thyroid diseases.

This article from the Oxford Medical Case Reports discusses a case of Graves' disease with thyroid hemiagenesis in a 35-year-old male patient. The patient presented with symptoms of easy fatigability and weakness in the legs. Upon examination, an elastic soft mass was found high in the middle of the neck, along with a soft right lobe of the thyroid gland. Ultrasonography revealed the absence of the left lobe of the thyroid gland. The patient was diagnosed with Graves' disease with thyroid hemiagenesis and a markedly enlarged pyramidal lobe. Treatment with thiamazole normalized the patient's thyroid function, but further interventions may be necessary in the future. The article also provides information on the rarity of detecting the thyroid pyramidal lobe in cases of Graves' disease with thyroid hemiagenesis. [Extracted from the article]

Introduction: the pyramidal lobe of the thyroid (PL) is an embryological remnant of the thyroglossal duct, established as a normal component of the thyroid gland, which can vary greatly in shape, position, appearance and size, and is not present in all individuals. Its prevalence can vary from 12% to 80% according to the type of study. Sua prevalência pode varia de 12% a 80% de acordo o tipo de estudo. Objective: to determine the frequency of occurrence and morphometry of the PL in human fetuses. Material and method: 24 thyroid glands of human fetus cadavers were dissected without the aid of optical instruments, 12 males and 12 females, whose general age ranged from 20.3 to 36.8 weeks, with an average of 26, 3 weeks. The fetuses were preserved in a 10% formaldehyde solution, and all measurements were performed using a 0.01 mm precision digital caliper. Results: the PL was found in 12.5% of the 24 thyroid glands studied, all females. The pyramidal lobes (PLs) originated from the upper margin of the isthmus of the thyroid gland, with 66.66% of the PLs located more to the left of the midline and 33.33% to the right. The length of the PLs ranged from 10.47 mm to 13.90 mm, with an average of 12.56 mm, and the width ranged from 3.04 mm to 3.39 mm, with an average of 3.25 mm. Conclusion: the knowledge of the normal anatomy and PL variations of the thyroid gland are essential for head and neck surgeons, especially in total thyroidectomy surgeries, as it can be affected by diseases that affect the rest of the thyroid parenchyma. [ABSTRACT FROM AUTHOR]

Introduction: About 5% of the world population is affected from various thyroid disorders. The present study is undertaken to describe the morphological and morphometric variations in the fetal thyroid glands of thyroid at different stages of development in the intrauterine life. Methodology: Forty medically terminated fetuses of both sexes ranging from 15 to 36 weeks of gestation were included. The external parameters recorded were: Fetal weight; crown-rump length; foot Length; Location; Presence/absence of isthmus; Presence of pyramidal lobe; Presence of an accessory thyroid tissue were observed in situ. The length, width, and thickness of each lobe and the isthmus were noted. Results: The specimens were categorized into three gestational groups, i.e., 10–20 weeks, 21–30 weeks, and 31–40 weeks. The statistical analysis suggests that there is significant increase in fetal thyroid weight, lengths and widths of the right and left lobes, and length of the isthmus with increase in gestational age. There was no significant increase in width of isthmus with gestational age. There was no significant difference in all thyroid parameters by gender. Conclusion: The data regarding the various parameters collected and analyzed in the present study emphasized the significance of an insight into the morphological variations, morphometric dimensions, and histological findings of foetal thyroid glands in diagnosing various diseases.

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 hyo-pyramidal 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, 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.

The pyramidal lobe, commonly known as the third lobe of the thyroid gland, arises from the isthmus or the surrounding region of any lobe toward the hyoid bone. The thyroglossal duct remnants form the pyramidal lobe of the thyroid. Clinically, it could be overlooked. The levetor glandulae thyroideae is a fibrous or fibromascular band that occasionally runs up from the summit of the pyramidal lobe to the body of the hyoid bone; in some cases, it began at the isthmus or neighboring region of any lobe. Study design: A descriptive cross-sectional study. Materials and Methods: From June 2018 to February 2019, this anatomical study was conducted at the Baghdad Institute of Forensic Medicine and the Kirkuk Teaching Hospital's forensic medicine section. For each sex, the collected samples were separated into two age groups: Group A 0 - 20 years (39 males and 21 females), and Group B 21 - 50 years (39 males and 21 females) (39 male and 21 female). The presence, position, extent, size, and histological diagnostic of the pyramidal lobe were perceived anatomically. The pyramidal lobe was detected in different age groups, with male specimens appearing more frequently than female specimens and levator glandulae thyroideae appearing slightly more frequently on the left side of the median-sagittal plane. The goal of this study was to see how characteristics like age and gender can affect changes in the pyramidal lobe's presence, position, relationship, and size, which is important to endocrinologists, pathologists, and ultrasonography specialists. Thyroid surgeons must also be familiar with the levator glandulae thyroideae in order to minimize iatrogenic damage. As a result, we believe that our findings can be used to achieve a harmless and more successful thyroidectomy to ovoid recurrent thyroid disease. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Surgical procedures on the thyroid are usually complicated by damage to the parathyroid glands, the external branch of superior laryngeal nerves, inferior laryngeal nerves, and hematoma due to vascular injury and the chance of residual thyroid tissue being left in case of cancer and Graves' disease, and the presence of anatomical variations. In this study, we describe the presence of a levator glandulae thyroideae that could misguide surgeons during surgical procedures.

Introduction: Ultrasound is the most reliable imaging modality for thyroid evaluation due to the limitations in the clinical examination of this gland. Thyroid gland developmental anomalies are rare. Most of its variations are due to the persistence of the thyroglossal duct and the absence of the isthmus. The aim of this study was to determine the incidence of pyramidal lobe and agenesis of the thyroid isthmus in Nnewi population using ultrasound. Materials and method: A total of 321 subjects resident in Nnewi, including 167 males and 154 females, were randomized. A written consent was obtained from all patients. The subjects were aged between 18 and 35 years. This was a prospective cross-sectional study. Thyroid glands were scanned using a 2-dimensional ultrasound machine with a 7.5 MHz transducer; model Siemens Sonoline Prima which was made in Japan for Siemens Medical System Incorporated, ultrasound Group, Issaquah, WA, 98029-7002, USA. Results: The study revealed no incidence of pyramidal lobe and agenesis of the thyroid isthmus in the study population. Conclusion: This study has clearly demonstrated no incidence of pyramidal lobe and agenesis of the thyroid isthmus in subjects resident in Nnewi, Nigeria.

Aim-Background: The pyramidal lobe is an important feature of thyroid gland anatomy that is often neglected in preoperative imaging and thyroid surgery. The aim of this review is to assess the frequency of the pyramidal lobe as well as its clinical importance. Methods: The search was conducted using the Medline database (1946 to February 2020). The key words of our search were "thyroid pyramidal lobe". The inclusion criteria specified the availability of abstracts or full-text articles in English. Out of 101 search results, 50 articles were relevant and were included in this study. Results: The prevalence of the pyramidal lobe in recent surgical and cadaveric studies varies between 12% – 65%. Identification rates in preoperative imaging are insufficient (ultrasonography accuracy: 80.3% – 83.7%, computed tomography accuracy: 92.6%). Ultrasonography appears less diagnostically accurate (accuracy: 82.1% – 87.5%) compared to computed tomography. The pyramidal lobe is commonly involved in thyroid pathology, especially in cancer and diffuse thyroid diseases, like Graves' disease and multinodular goiter. Conclusions: The pyramidal lobe is a normal component of thyroid anatomy. Intraoperative pyramidal lobe identification and resection is mandatory, in order to prevent disease recurrence. [ABSTRACT FROM AUTHOR]

Background: The thyroid gland, a highly vascular endocrine gland, is composed of two lateral lobes connected by isthmus. A wide range of morphological alterations of the thyroid gland such as hypoplasia, ectopy to hemiagenesis, and genesis are common because of disturbed embryogenesis. The significance of diagnosing such extensions of the thyroid gland is crucial. It may alter the normal anatomical relationship of the thyroid gland with other adjacent cervical structures. Further, it may be confused with a tumor mass on magnetic resonance imaging and scintillation scans. Methods: The primary aim is to study the thyroid gland for gross anatomical variations (weight, height, and breadth) and secondarily to document the morphometric and congenital/developmental variation gross of the thyroid gland in 65 cadavers from the coastal belt of South India. The glands were according to the various age groups of the cadavers. Results: The mean thyroid weight was 26.01 ± 7.14 g. In males, it was 26.59 ± 6.96 g, whereas in females, it was 20.93 ± 8.98 g. The pyramidal lobe was present in 35 (53.8%), and the presence of the levator glandulae thyroideae was noted in 25 (38.48%) of male cadavers. Agenesis of the isthmus was found in 20 (30.76%). However, the accessory thyroid tissue was found in only one female cadaver. Conclusions: Our morphometric study on cadaveric thyroid glands highlights individual and ethnic variations. Knowledge of various developmental anomalies and unusual variations of the thyroid gland is of paramount importance to differentiate it from other pathologies such as autonomous thyroid nodule and thyroiditis. [ABSTRACT FROM AUTHOR]

Knowledge of the variations of the pyramidal lobe of the thyroid is important for surgeons to perform complete resection of the functional thyroid tissue. Complete excision of the thyroid tissue surgery reduces the chances of recurrence in both the benign and the malignant diseases. It is important to remove all functioning thyroid tissue especially in the differentiated thyroid cancer so the postoperative radioiodine ablation is more effective and serum thyroglobulin acts as an efficient marker. We report a case of the double pyramidal lobe of thyroid gland in a woman of age 63 years with follicular thyroid cancer. Our literature search revealed only three documented cases of the double pyramidal lobe. Knowledge and recognition of such a rare variation is essential to perform safe and effective thyroid surgery. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the variation patterns of thyroid glands in embalmed cadavers donated for anatomical studying and research in the northeastern part of Thailand. The crossed-sectional descriptive study was applied to systemically observe the thyroid gland in abnormality of 45 embalmed cadavers. The study was conducted in the Anatomy Laboratory of College of Medicine and Public Health, Ubon Ratchathani University. The indications of thyroid gland abnormalities were recorded by photographs before classification of data used further in a descriptive analysis using SPSS. The results showed that 8 of the 45 cadavers (17.8 %) were observed with thyroid gland abnormality (4 males; 8.9 % and 4 females; 8.9 %). Such variations could be classified into 3 types; pyramidal lobe (8.8 %), levator glandulae thyroideae (2.2 %) and the co-existing of levator glandulae thyroideae (8.8 %), respectively. The thyroid gland abnormality observed in this study was mainly related to many previous reports. Besides the number of thyroid variations are a crucial indication of thyroid gland abnormality recurring, these gland abnormalities are susceptible to the operation of radiology physicians in thyroidectomy and tracheostomy. [ABSTRACT FROM AUTHOR]

Surgical procedures are usually the treatment of choice when managing severe neck and thyroid-related pathologies; however, they become complicated by damage to the parathyroid glands, the external branch of superior laryngeal nerves, inferior laryngeal nerves, and hematoma due to vascular injury and the chance of residual thyroid tissue being left in case of cancer and Graves' disease, and the presence of anatomical variations. Therefore, prior knowledge of the incidence of anatomic anomalies would ensure avoidance of such complications. In this study, we describe the presence of a levator glandulae thyroideae that could misguide surgeons during surgical procedures. [ABSTRACT FROM AUTHOR]

Because of its embryonic origin, the thyroid gland is predisposed to multiple anatomical variations and developmental anomalies. These include the pyramidal lobe, the origin of levator glandular thyroidae, the absence of the isthmus, ectopic thyroid, accessory thyroid tissues, etc. These anatomical variations are clinically significant to surgeons, anatomists, and researchers. The present study was designed to report anatomical variations and developmental anomalies of the thyroid gland in Ethiopian population. The study was conducted on 40 cadavers used for routine dissection classes. The thyroid gland was exposed and observed for any variations and developmental anomalies. The length, width, and thickness of the lobes were measured using a vernier caliper. Differences in the incidence of pyramidal lobe and absence of the isthmus between sexes were tested using a Pearson chi-square test. The mean length, width, and thickness of the right lobe were 4.24 cm, 1.8 cm, and 1.6 cm, respectively, whereas it was 4.08 cm, 1.8 cm, and 1.6 cm, respectively for that of the left lobe. The pyramidal lobe was noted in 52.5% of the cadavers. The levator glandulae thyroidae were prevalent in 40% of the cadavers. The isthmus mainly overlies the 2nd to 4th tracheal rings and was absent in 7.5% of the cadavers. Accessory thyroid tissue and double pyramidal lobes were noted in 2.5% of the cadavers. Most of the variations of the thyroid gland were seen frequently in female but it was not statically significant. Different clinically important and rare variations of the thyroid gland were found. [ABSTRACT FROM AUTHOR]

Introduction: Ultrasound is the most reliable imaging modality for thyroid evaluation due to the limitations in the clinical examination of this gland. Thyroid gland developmental anomalies are rare. Most of its variations are due to the persistence of the thyroglossal duct and the absence of the isthmus. The aim of this study was to determine the incidence of pyramidal lobe and agenesis of the thyroid isthmus in Nnewi population using ultrasound. Materials and method: A total of 321 subjects resident in Nnewi, including 167 males and 154 females, were randomized. A written consent was obtained from all patients. The subjects were aged between 18 and 35 years. This was a prospective cross-sectional study. Thyroid glands were scanned using a 2-dimensional ultrasound machine with a 7.5 MHz transducer; model Siemens Sonoline Prima which was made in Japan for Siemens Medical System Incorporated, ultrasound Group, Issaquah, WA, 98029-7002, USA. Results: The study revealed no incidence of pyramidal lobe and agenesis of the thyroid isthmus in the study population. Conclusion: This study has clearly demonstrated no incidence of pyramidal lobe and agenesis of the thyroid isthmus in subjects resident in Nnewi, Nigeria. [ABSTRACT FROM AUTHOR]

Thyroid lobes are supplied by superior and inferior thyroid arteries. We dissected out a specific arterial pattern always present along with a well developed pyramidal lobe. Authors named this as “Pyramidal Artery”. This may be a common unnoticed bleeding site during surgery. Thyroid anomalies are commonly observed as incidental finding during surgery. Presence of pyramidal lobe is the most common finding among other thyroid anomalies due to persistence of thyroglossal duct. Present study reported incidence of pyramidal lobe in 41.46% cases and pyramidal lobe branches off more frequently from left lobe than right. Special attention has to be paid during total thyroidectomy in order not to leave the thyroid tissue. Few such anatomical variations and surgical importance of vascular pattern in such cases is discussed in paper. [ABSTRACT FROM AUTHOR]

Introduction: Thyroid gland is an organ with a highly variable morphology. Despite several studies having been done to assess its measurements, a consensus has not been arrived at as to what constitutes a ‘normal’ thyroid. Aim: To determine the dimensions of the normal thyroid gland obtained from cadavers of South Indian region and to derive the mean and standard deviations of the measurements of the gland in the given population, thus contributing to the existing data. We also aimed to study three common but not constant components of the thyroid gland, namely Pyramidal Lobe (PL), Tubercle of Zukerkandl (TZ) and Levator Glandulae Thyroideae (LGT). Materials and Methods: The study was conducted on thyroid glands obtained from cadavers of South Indian region. Institutional ethics committee approval was obtained. Sixty thyroid glands were obtained from cadavers received for either routine dissection or autopsies. The thyroid glands were studied after adequate exposure and fixing in formalin. Dimensions were measured using Vernier calipers. Specimens with anomalies like absent isthmus etc were excluded from the study. Statistical analysis was done using the MedCalc Version 17.0 software. Results: The average dimensions of the lobes were: height 3.83 cm, width 2.62 cm, and thickness 2.69 cm. The average dimensions of the isthmus were: height 1.38 cm, width 1.36 cm and thickness 1.29 cm. The average dimensions of the pyramidal lobe were: height 2.03 cm, width at the base 1.91 cm and thickness 1.16 cm. Pyramidal lobe was present in 60% of cases. Levator glandulae thyroideae was observable in three cases (5%). Significant correlation was found between the dimensions of right and left lobes and regression equations were calculated. Conclusion: The dimensions of the thyroid gland are very variable. Knowledge of the wide ranging variations and measurements will be of help to surgeons and radiologists in correct interpretation, diagnosis and treatment of thyroid diseases.

We report an extremely rare case of papillary thyroid microcarcinoma (PTMC) in the thyroid Epub ahead of print pyramidal lobe (TPL). A 48-year-old woman underwent ultrasound-guided fine-needle aspiration for a small thyroid nodule in the right lobe in local clinic, and it revealed a malignant cytology. On preoperative ultrasonography for tumor staging in our hospital, another small suspiciously malignant hypoechoic nodule was detected in the left TPL. Total thyroidectomy and central nodal dissection were performed. Histopathology confirmed PTMCs in the left TPL and both thyroid lobes. Ultrasonography for TPL should be required for complete evaluation of possible multifocality of thyroid malignancy.

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., (© 2023 American Association of Clinical Anatomists and British Association of Clinical Anatomists.)

Introduction: The morphological variations of the thyroid gland have been reported from different parts of the world. The variations are due to remnant or non-specific development of the parts of the thyroid gland. Surgical operation of the thyroid gland has been the treatment of choice in various thyroid pathologies. Prior knowledge of the morphological variation is important to ensure better results from these surgical operations. Aim: To study the prevalence of morphological variations seen in the thyroid glands in the upper Assam region of Northeast India. Materials and Methods: This was a hospital based cadaveric study. Total number of Thyroid glands dissected were 80. The thyroid gland was examined properly for the presence of pyramidal lobe, levator glandulae thyroideae and complete absence of isthmus. Statistical analysis was done by SPSS 21.0. Results: It was found that 17 (21.25%) cadavers did not show an isthmus. The pyramidal lobe was present in 31(38.75%) cases and frequently arising from the left side (74.2%) of the isthmus. Levator glandulae thyroideae was found in 15 (18.75%) of the thyroid specimens. In all cases, it was extended from the apex of the pyramidal lobe to the hyoid bone. Conclusion: Morphological variation of the thyroid gland is very common hence requires detection prior to any surgery on the thyroid gland.

Purpose: The purpose was to find out the efficacy of fixed 15 mCi radioactive iodine-131 (RAI) dose and predictive values of various factors for inducing hypothyroidism in Graves' disease (GD). Materials and Methods: Retrospective study conducted from January 2012 till August 2014. Patients with GD who had a technetium-99m thyroid scan, thyroid antibodies, received fixed 15 mCi RAI and did follow endocrine clinics for at least 6 months were selected. RAI was considered successful if within 6 months of RAI therapy patients developed hypothyroidism. Results: Of the 370 patients with GD who had RAI during study period, 210 (57%) qualified study criteria. Mean age of patients was 48 ± 15 years with female: male ratio of 69:31, positive thyroid antibodies in 61%, means thyroid uptake of 15.09 ± 11.23%, and presence of pyramidal lobe in 40% of total population. Hypothyroidism was achieved in 161 (77%) patients while 49 (23%) patients failed to achieve it (remained either hyperthyroid or euthyroid on antithyroid medication). Patients who became hypothyroid were significantly younger with higher proportion of presence of thyroid antibodies and pyramidal lobe and lower percentage thyroid uptake than those who failed. Multiple logistic regression analysis revealed that age (odds ratio; OR = 2.074), pyramidal lobe (OR = 3.317), thyroid antibodies (OR = 8.198), and percentage thyroid uptake (OR = 3.043) were found to be significant prognostic risk factors for post-RAI hypothyroidism. Gender was found to have nonsignificant association with the development of hypothyroidism. Receiver operating characteristic analysis revealed age <42 years and thyroid uptake <15% as threshold values for the development of post-RAI hypothyroidism. Conclusion: We conclude that fixed (15 mCi) RAI dose is highly effective in rendering hypothyroidism in patients with GD. Age (≤42 years), thyroid uptake (≤15%) and presence of pyramidal lobe are strong predictors of hypothyroidism and must be considered for selecting optimal RAI dose. [ABSTRACT FROM AUTHOR]

To investigate developmental changes in the thyroglossal duct, we observed serial sagittal sections of eight embryos (crown-rump length (CRL) 6–12 mm; approximately 5–6 weeks of gestation) as well as serial horizontal or cross-sections of 70 embryos and fetuses (CRL 15–110 mm; 6–15 weeks). In the sagittal sections, the thyroglossal duct was identified as a small sheet or mass of relatively large cells with vacuolization anterior, superior or inferior to the fourth pharyngeal arch artery. However, we found no continuous duct-like structure that reached the thyroid gland. Thus, previous classical schemes might have overestimated the continuity of the duct. Among cross-sections of 70 specimens, we found the thyroglossal duct remnant in only two specimens (CRL 15 mm and 100 mm), in contrast to the pyramidal lobe, which was seen in one-third of the specimens. The duct remnant ran downward along the lateral edge of the hyoid body to reach the anterior aspect of the thyroid cartilage. However, the connection between the pyramidal lobe and the duct remnant was interrupted by the anterior cervical muscles. Therefore, it was unlikely that the thyroglossal duct remnant would more frequently be evident in fetuses than in adults. The highly tortuous course of the duct along the lingual aspect of the hyoid body, which has been reported previously, appeared to become established near term. Descent of the thyroid gland was not evident after the CRL 20 mm stage (6 weeks): the gland appeared to retain its position at the level of the third–sixth cervical vertebrae. [ABSTRACT FROM AUTHOR]

A wide range of morphological and developmental variations of thyroid gland like hypoplasia, ectopic thyroid tissue, hemiagenesis or agenesis of thyroid gland has been reported. Out of these agenesis of the thyroid isthmus is a very rare congenital anomaly. Thyroid isthmus agenesis does not manifest clinical symptoms, and it can be confused with other thyroid pathologies. Also the presence of levator glandulae thyroideae and its anatomical variations gain importance in the pathologies which are related to thyroid gland and their treatment modalities. We hereby, report the absence of isthmus and presence of levator glandulae thyroideae and pyramidal lobe in a middle aged male cadaver. The present case report is an attempt to highlight the implications of variation of thyroid gland from diagnostic, phylogenetic and functional perspectives. [ABSTRACT FROM AUTHOR]

Abstract: This study aimed to assess the diagnostic accuracy of pre-operative ultrasound (US) and computed tomography (CT) for detecting thyroid pyramidal lobe (TPL). A single radiologist prospectively performed thyroid US and retrospectively reviewed neck CT to detect TPLs in 135 consecutive patients scheduled for thyroid surgery. The location, size and superior extent of each TPL and its separation or continuity with the main thyroid gland were assessed by thyroid US, neck CT and surgery. The prevalence of TPLs as diagnosed by thyroid US, neck CT and surgery was 58.5% (79/135), 56.3% (76/135) and 60% (81/135), respectively. We compared US and CT detection of TPLs with surgical data to determine their sensitivity (85.2% and 91.4%), specificity (81.5% and 94.4%), positive (87.3% and 96.1%) and negative (78.6% and 87.9%) predictive values and accuracy (83.7% and 92.6%). For detecting TPLs, both neck CT and thyroid US have good diagnostic value, although neck CT is more accurate than thyroid US. [Copyright &y& Elsevier]

Thyroid surgery is a prototype of operations requiring thorough knowledge of surgical anatomy. There are many vital and delicate anatomical structures such as recurrent laryngeal nerve, superior laryngeal nerve, parathyroid glands, and distinct fascial planes surrounding the thyroid gland. A protean range of pathologies such as goiter, nodules, thyroiditis, and malignancy distort or alter the location and course of these structures and planes. The distinct vascular supply and high vascularity of thyroid region challenges the surgeon's expertise. Several pathologies like malignancy, multinodularity, toxicity, and retrosternal extension further compounds this vascular aspect of surgery. Several structures of embryological importance such as pyramidal lobe, tubercle of Zuckerkandl, and ligament of Berry have decisive clinical implications in the surgical management of thyroid disorders. Surgeons attempting thyroidectomy need to have thorough knowledge of embryology and surgical anatomy of the thyroid gland. In this context, we highlight through a pictorial assay the embryological and anatomical aspects of the thyroid gland emphasizing on their clinical and surgical importance. [ABSTRACT FROM AUTHOR]

Purpose: Thyroid pyramidal lobe (TPL) is a normal variant of the thyroid gland, but few imaging studies of TPL have been published. The purpose of this study is to investigate the frequency, location, size (length, maximal AP diameter, maximal transverse diameter), and upper end level of TPL with its separation from the main thyroid gland on preoperative neck CT and to compare them with operative findings in order to assess the diagnostic accuracy of neck CT for detection TPL. Materials and Methods: 46 patients, who underwent preoperative neck CT before thyroidectomy, were included in the study. The frequency, location, size, and upper end level of TPL with its separation from the main thyroid gland on the neck CT was analyzed by a single radiologist. Results: The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of neck CT for detecting TPL was 77.8%, 89.5%, 91.3%, 73.9% and 82.6%. There was a significant difference in maximal AP diameter, location, upper end level, and its separation from main thyroid gland between CT and operative findings (p < 0.05), but there was no significant difference in the length and maximal transverse diameter of TPL (p > 0.05). Conclusion: Diagnostic accuracy of neck CT for detecting TPL was high, and the neck CT may be useful for evaluating TPL in the suprahyoid neck. [ABSTRACT FROM AUTHOR]

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 categorized the shape of the thyroid into 12 types. The most frequent type was PYR-L with 22.5% which started from the left lobe and moved across by intercrossing the larynx. Horseshoe-shaped gland and the gland with separate lobes were the most frequently observed glandular shapes, with 17.5 and 20%, respectively. The incidences of the PYR-L and the levator glandulae thyroideae were 60 and 17.5%, respectively. The pyramidal lobe branched off more frequently from the left part of the isthmus (14 specimens) than from the right (5 specimens) or the midline (2 cases). Knowledge about the glandular landmarks and anatomic measurements around the thyroid will be helpful for the surgeon to constitute a simplification of the topographic anatomy, plan and decide on a safe approach to the thyroid gland, and to avoid postoperative complications. [ABSTRACT FROM AUTHOR]

The pathophysiology of thyroid dysgenesis remains unclear and, until recently, this disorder was generally regarded as sporadic. However, a small but significant proportion of familial cases have been identified (2%) through the study of subjects with congenital hypothyroidism, and more recent work has revealed an even higher proportion of familial thyroid dysgenesis in both symptomatic and asymptomatic individuals. These studies strongly suggest the existence of a familial component of this disorder involving dominant genetic predisposition factors with a low penetrance. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Introduction: The morphological variations of the thyroid gland have been reported from different parts of the world. The variations are due to remnant or non-specific development of the parts of the thyroid gland. Surgical operation of the thyroid gland has been the treatment of choice in various thyroid pathologies. Prior knowledge of the morphological variation is important to ensure better results from these surgical operations. Aim: To study the prevalence of morphological variations seen in the thyroid glands in the upper Assam region of Northeast India. Materials and Methods: This was a hospital based cadaveric study. Total numbers of Thyroid glands dissected were 80. The thyroid gland was examined properly for the presence of pyramidal lobe, levator glandulae thyroideae and complete absence of isthmus. Statistical analysis was done by SPSS 21.0. Results: It was found that 17 (21.25%) cadavers did not show an isthmus. The pyramidal lobe was present in 31(38.75%) cases and frequently arising from the left side (74.2%) of the isthmus. Levator glandulae thyroideae was found in 15 (18.75%) of the thyroid specimens. In all cases, it was extended from the apex of the pyramidal lobe to the hyoid bone. Conclusion: Morphological variation of the thyroid gland is very common hence requires detection prior to any surgery on the thyroid gland. [ABSTRACT FROM AUTHOR]

Introduction: To study the characteristics of pyramidal lobe (PL) in cancer patients with emphasis on its involvement in patients subjected to thyroidectomy at a tertiary care cancer centre.Methods: Retrospective review of prospectively maintained data of 103 patients (33 males and 70 females) who underwent thyroidectomy from January 1st 2011-August 31st 2013. Surgery was performed by single surgeon, findings recorded by the lead author and all measurements taken with specimen in situ prior to mobilization of thyroid gland with intact anatomy. Thyroid specimens were examined for presence, location, length and histology of PL.Results: PL was identified in 38 (36.89%) patients. PL was commoner on left 27 (71.05%) compared to 11 (28.95%) on right side. The frequency of PL was higher in males 51.51% compared to females 30%. The length varied from 4 to 35 mm. The mean length was 18.0 ± 12.4 mm. In 10.53% cases PL contained deposits of papillary carcinoma of thyroid.Discussion: Meticulous clearance of disease is of utmost importance in thyroid cancer surgery in order to prevent recurrence and ensure reliable follow up with serum thyroglobulin. PL is a common site of residual thyroid tissue which if involved by cancer can be a cause of local recurrence.Conclusions: PL is a well established entity which is present in over one third of patients. Efforts should be made to identify PL during surgery given its bearing on the management of thyroid carcinoma as nearly 10% of these will be site of multifocal papillary carcinoma. [ABSTRACT FROM AUTHOR]