Zuckerkandl tubercle of the thyroid: a common imaging finding that may mimic pathology

A Rare Variant of Zuckerkandl Tubercle: Thyroid Ring

Zuckerkandl tubercles are posteromedial projections of normal thyroid gland with relations with important neck structures. In our case, we reported "Thyroid ring", that is a ring configuration of the thyroid gland encasing the trachea and esophagus, without compression symptoms. Ring was formed by the elongated zuckerkandl tubercles, passing through the column between the esophagus and vertebral body and abutting each other at left posterolateral border of esophagus. Reporting of these relations and variations is important as it helps the operating surgeon in planning the approach to the procedure.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12070-023-04079-4.

Evaluation of thyroid Zuckerkandl tubercle by computed tomography

PURPOSE

This study investigated the incidence of thyroid Zuckerkandl Tubercle (ZT) using a computed tomography (CT) scan of the neck with contrast to identify the typologies in ZT-positive CT scans, investigate the presence of nodules located in that area, and compare the results with the relevant literature.

METHODS

We selected and retrospectively examined the CT scan images of patients who presented to our clinic with CT scans of the neck with contrast that clearly showed thyroid tissue and boundaries. Patients were evaluated based on age, gender, and presence of thyroid ZT. Patients with thyroid ZT were further investigated for localization and type of tubercles as well as for presence of nodules at the tubercle level.

RESULTS

A total of 1000 patients (mean age: 48.4 ± 19.1) were included in the study. Out of the total 222 (22.2%) patients who had thyroid ZT, 134 (60.4%) patients had unilateral thyroid ZT on the right side and 29 (13.1%) patients had unilateral thyroid ZT on the left side; 59 (26.6%) patients had bilateral thyroid ZT. In addition, nodules at the ZT level were observed in 13 (1.3%) of the patients. A review of all cases with ZTs indicated that 63% were Type 1, 31% were Type 2, and 5% were Type 3.

CONCLUSION

During the thyroid operations, ZT is essential for locating the recurrent laryngeal nerve. Reporting the presence of ZTs based on CT scans is crucial because it can prevent unnecessary interventional procedures, misdiagnoses, and likely complications in patients with planned thyroid operations.

Ultrasound Imaging of Cervical Anatomic Variants

Embryologic developmental variants of the thyroid and parathyroid glands may cause cervical anomalies that are detectable in ultrasound examinations of the neck. For some of these developmental variants, molecular genetic factors have been identified. Ultrasound, as the first-line imaging procedure, has proven useful in detecting clinically relevant anatomic variants. The aim of this article was to systematically summarize the ultrasound characteristics of developmental variants of the thyroid and parathyroid glands as well as ectopic thymus and neck cysts. Quantitative measures were developed based on our findings and the respective literature. Developmental anomalies frequently manifest as cysts that can be detected by cervical ultrasound examinations. Median neck cysts are the most common congenital cervical cystic lesions, with a reported prevalence of 7% in the general population. Besides cystic malformations, developmental anomalies may appear as ectopic or dystopic tissue. Ectopic thyroid tissue is observed in the midline of the neck in most patients and has a prevalence of 1/100,000 to 1/300,000. Lingual thyroid accounts for 90% of cases of ectopic thyroid tissue. Zuckerkandl tubercles (ZTs) have been detected in 55% of all thyroid lobes. Prominent ZTs are frequently observed in thyroid lobes affected by autoimmune thyroiditis compared with normal lobes or nodular lobes (P = 0.006). The correct interpretation of the ultrasound characteristics of these variants is essential to establish the clinical diagnosis. In the preoperative assessment, the identification of these cervical anomalies via ultrasound examination is indispensable.

Pediatric hyperparathyroidism: review and imaging update

Hyperparathyroidism, due to increased secretion of parathyroid hormones, may be primary, secondary or tertiary. Most pediatric patients with sporadic primary hyperparathyroidism will be symptomatic, presenting with either end-organ damage or nonspecific symptoms. In younger patients with primary hyperparathyroidism, there is a higher prevalence of familial hyperparathyroidism including germline inactivating mutations of the calcium-sensing receptor genes that result in either neonatal severe hyperparathyroidism or familial hypocalciuric hypercalcemia. Parathyroid scintigraphy and ultrasound are complementary, first-line imaging modalities for localizing hyperfunctioning parathyroid glands. Second-line imaging modalities are multiphase computed tomography (CT) and magnetic resonance imaging. In pediatrics, multiphase CT protocols should be adjusted to optimize radiation dose. Although, the role of these imaging modalities is better established in preoperative localization of hyperfunctioning parathyroid glands in primary hyperparathyroidism, the same principles apply in secondary and tertiary hyperparathyroidism. In this manuscript, we will review the embryology, anatomy, pathophysiology and preoperative localization of parathyroid glands as well as several subtypes of primary familial hyperparathyroidism. While most of the recent imaging literature centers on adults, we will focus on the issues that are pertinent and applicable to pediatrics.

Ultrasound of the Normal Thyroid with Technical Pearls and Pitfalls

Ultrasound is the best imaging modality for comprehensive evaluation of the thyroid. The thyroid is best imaged using a high-frequency linear probe with the patient in a supine position with the neck hyperextended. Normal thyroid is homogeneous in appearance without defining anatomic landmarks within the gland. A few anatomic variants can occur, and it is important for the sonographer and radiologist to be aware of these variants, to avoid misidentifying them as a pathology. This article provides a comprehensive review of ultrasound of the normal thyroid gland, including technique, normal anatomy, anatomic variants, imaging appearance, and technical pearls and pitfalls.

Thyroid Tubercle of Zuckerkandl May Not Arise from the Ultimobranchial Body: Results from Histological Analysis

Thyroid tubercle of Zuckerkandl (TZ) is a nodule arising from the posterolateral thyroid, considered to be a remnant of the ultimobranchial body (UB). Considering that C cells and solid cell nests also arise from the UB, we hypothesized that these would be present in the TZ. We examined the presence of C cells and solid cell nests in the TZ using the histological analyses of 21 patients with grade 2 or 3 TZs following Pelizzo's grading system. Out of 21 TZs, 19 (90.5%) were located in the right lobe of the thyroid. Microscopically, solid cell nests were found within the TZ in 1 case (4.8%), and within the main thyroid tissues in 3 cases (14.3%). Calcitonin-positive C cells were scattered within the TZ in 1 case (4.8%), and within the main thyroid tissue in 15 cases (71.4%). The distribution of C cells within the main thyroid tissue was denser than that within the TZ. The above-mentioned results indicated the lack of C cells and solid cell nests in the TZ. Although the TZ may have an embryological origin different from that of ordinary thyroid tissue, it is unlikely that the remnants of the UB are involved in the formation of the TZ.

Normal ultrasound anatomy and common anatomical variants of the thyroid gland plus adjacent structures - A pictorial review

BACKGROUND

High-resolution ultrasound is considered the best imaging technique for evaluating the thyroid gland, as it is accessible, non-invasive, and highly sensitive concerning the detection and characterization of thyroid nodules. However, a background knowledge of the normal ultrasound anatomy of the thyroid gland, adjacent structures, and its anatomical variants is crucial to avoid misdiagnosis in daily practice. Through this pictorial review, we intend to.

Zuckerkandl Tubercle of the Thyroid Gland: Correlations between Findings of Anatomic Dissections and CT Imaging

BACKGROUND AND PURPOSE

The Zuckerkandl tubercle is located at the posteromedial border of the thyroid lobe, and it may be confused with a neoplasm or other mass. This study was performed to clarify the position and morphologic characteristics of the Zuckerkandl tubercle by dissecting cadavers and to compare the findings with the corresponding CT images obtained in the same cadavers.

MATERIALS AND METHODS

One hundred thyroid lobes from 50 fresh cadavers were dissected for this study (20 males and 30 females; mean age at death, 77.3 ± 11.5 years). CT scans were obtained in 10 of the cadavers by using a 128-channel multidetector row CT scanner before dissection.

RESULTS

The Zuckerkandl tubercle of the thyroid gland was observed in 83% of the specimens. It was mostly located at the posteromedial border of the thyroid lobe and within the middle two quarters (2nd and 3rd) of the thyroid lobe. The Zuckerkandl tubercle was classified into 3 types based on its direction of extension: posteromedial in 64% of the specimens, posteromedial and superior in 13%, and posteromedial and inferior in 6%. On axial CT, the Zuckerkandl tubercle was usually continuous with the posteromedial part of the thyroid lobe and extended posteromedially to the esophagus. The parts of the Zuckerkandl tubercle that protrude posteromedially and superiorly or posteromedially and inferiorly from the thyroid lobe appeared separated from the thyroid gland by a thin, low-density string on axial CT.

CONCLUSIONS

Zuckerkandl tubercles that protrude toward the posteromedial and superior or inferior direction could cause confusion due to their separation when performing diagnoses with CT images.

Zuckerkandl's tubercle and its relationship to the recurrent laryngeal nerve: A cadaveric dissection and meta-analysis

OBJECTIVE

Zuckerkandl's tubercle (ZT), when present, is an anatomical landmark by which surrounding structures such as the recurrent laryngeal nerve (RLN) can be identified intraoperatively. This study aimed to investigate the prevalence and anatomical characteristics of Zuckerkandl's tubercle by combining cadaveric dissection with a meta-analysis.

METHODS

Through October 2016, an extensive search of PubMed, CNKI, ScienceDirect, EMBASE, BIOSIS, SciELO, and Web of Science was completed. Extracted data, along with the findings from our cadaveric dissections, were pooled into a meta-analysis to assess the prevalence and size of ZT and its relationship to the RLN.

RESULTS

The pooled prevalence estimate of a ZT was 70.2% in the general population, 65.0% of which were considered Grade 0 tubercles (<1.0cm) and 35.0% Grade 1 (≥1.0cm). The RLN ran posteromedially to the ZT in 82.7% of cases, laterally to it in 8.7%, and on top of it in 8.6% of hemilarynges.

CONCLUSION

RLN palsy is a common postoperative complication and cause for litigation following neck surgery. The ZT is a common component of the thyroid gland and with proper knowledge, surgeons can use it to reliably and quickly identify the RLN during operative procedures.

Anatomic Eponyms in Neuroradiology: Head and Neck

In medicine, an eponym is a word-typically referring to an anatomic structure, disease, or syndrome-that is derived from a person's name. Medical eponyms are ubiquitous and numerous. They are also at times controversial. Eponyms reflect medicine's rich and colorful history and can be useful for concisely conveying complex concepts. Familiarity with eponyms facilitates correct usage and accurate communication. In this article, 22 eponyms used to describe anatomic structures of the head and neck are discussed. For each structure, the author first provides a biographical account of the individual for whom the structure is named. An anatomic description and brief discussion of the structure's clinical relevance follow.

Zuckerkandl tubercle in thyroid surgery: Is it a reality or a myth?

Background

Zuckerkandl tubercle (ZT) is a lateral projection from the lateral thyroid lobe which is a constant landmark for finding the recurrent laryngeal nerve during thyroid surgery. It is the condensed thyroid parenchyma located in the cricothyroid junction. Even today, ZT and its relationship with recurrent laryngeal nerve (RLN) is not well known by all surgeons. The objectives of the present study were to find out the incidence of ZT in our thyroidectomies and to investigate whether the ZT has a relationship with RLN. We also discussed how to prevent RLN injury during thyroidectomy.

Materials and methods

One hundred operations were performed by the same surgeon included in this study. All operations performed with intraoperative neuromonitorization (IONM) for proving the visualization of RLN. In each patient, particularly the ZT and its relationship with RLN searched and recorded. We also analyzed the patients in terms of sex, age, clinical diagnosis, and types of performed operations.

Results

In 100 operations, 173 thyroid lobectomies were considered. 87 of these lobectomies were in right side and 86 in left side. The ZT was determined in 127 of 173 (73.41%) lobectomies. ZT was detected in 68 (78.16%) of right thyroid lobes whereas in 59 (68.60%) of left thyroid lobes. We observed that the ZT was detected more frequently in the right side. In 115 (90.55%) of these occasions, the recurrent nerve was directed upwards covered by the ZT.

Conclusions

If it is present, ZT is a real constant landmark pointing to the RLN. In order to find and protect RLN during thyroid surgery, a careful, bloodless, and meticulous dissection should be carried out around the ZT. Although our results are encouraging, further researches are still needed on this topic.

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Zuckerkandl tubercle (ZT) is a lateral projection from the lateral thyroid lobe.

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Even today, ZT and its relationship with recurrent laryngeal nerve (RLN) is not well known by all surgeons.

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If it is present, ZT is a real constant landmark pointing to the RLN.

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In order to find and protect RLN during thyroid surgery, a careful dissection should be carried out around the ZT.

Zuckerkandl's tubercle of the thyroid gland: Its location in the anatomical position, and comparative morphology of the same specimens before and after fixation

The aim of this study was to elucidate the definition of the borders and surface of the thyroid lobe in the anatomical position, and to compare the morphology of Zuckerkandl's tubercle (ZT) in the fresh and fixed states. One hundred thyroid lobes from 50 fresh Korean cadavers were used. The lateral border of the thyroid lobe could be defined as the most lateral margin of its anterior aspect when in the anatomical position. The posteromedial border was the margin that projected toward the trachea or tracheoesophageal groove. The lateral and posteromedial borders, and the posterior surface between these borders, could be identified in most of the fixed cadavers. The posterolateral border could only be identified in the thyroid lobe if there was compression by the internal carotid artery in cross-sectioned specimens and CT images. The ZT was identifiable in 85% of both fresh and fixed specimens. It was identified mainly at the posteromedial border of the thyroid lobe when in the anatomical position, and extended to the tracheoesophageal groove or esophagus. In the fresh state, the ZT projected as a rounded cone with a usually semicircular base, but its shape was very variable in the fixed state. In the present study, the ZT was found at the posteromedial border or posterior surface of the thyroid lobe in both the fresh and fixed states, contrary to most previous reports. The location of the ZT should be established in the anatomical position to avoid confusion.

131I abnormal uptake by the thyroid bed from Zuckerkandl tubercle diagnosis by 131I SPECT/CT

After thyroid remnant ablation following total thyroidectomy for thyroid cancer, 131I SPECT/CT revealed 131I uptake, regarded as thyroid bed uptake on planar images, in the anterior cervical region. On SPECT/CT, the 131I uptake focus appeared at the esophagus, suggesting esophageal invasion. No esophageal invasion had been recognized intraoperatively, and no residual uptake was detected by 131I scintigraphy evaluating therapeutic effects 3 months after ablation. Preoperative CT revealed a retrotracheal space portion extending from the normal thyroid with the same density, suggesting Zuckerkandl tubercle. Abnormal uptake on SPECT/CT was deemed Zuckerkandl tubercle-derived thyroid bed uptake.