Ectopic Thyroid Research Articles

Outcomes of newborns screened for congenital hypothyroidism in Turkey – a single center experience

Abstract Objectives It was aimed to investigate the outcomes of babies referred to a tertiary health center in Turkey for evaluation primary congenital hypothyroidism (CH) through newborn screening. Methods The hospital files of 328 newborns who were referred for CH from newborn screening between June 2013 and June 2020 were retrospectively reviewed. The newborns were evaluated with their clinical characteristics at admission, as well as their follow-up data and final diagnoses. Results Sixteen (4.9 %) newborns were diagnosed with transient neonatal hyperthyrotropinemia after follow-up. Treatment was initiated in 166 (50.6 %) of the cases with a diagnosis of CH. The median age at initiation of treatment was 17 days (5–69). Treatment was initiated in 88.3 % of the cases in the first month of the life. After at least 3 years of follow-up, 30/120 (20.0 %) of the cases were diagnosed with permanent CH and 11/30 (36.7 %) of them were diagnosed with thyroid dysgenesis. All of the cases who used >37.5 µg per day levothyroxine at the age of 1 or 2 years were diagnosed with permanent CH during their follow-up. For the prediction of transient CH, the sensitivity and specificity of levothyroxine doses of ≤25 µg per day at 1 year of age were calculated as 96.2 and 46.2 %, and for 2 years of age, the sensitivity and specificity were calculated as 97.8 and 65.2 %. Conclusions In this cohort, 10 % of all referrals result in permanent CH. Thyroid imaging with ultrasonography and levothyroxine dose during follow-up can be guiding in predicting permanent CH.

Case report: Benign lateral neck ectopic thyroid tissue mimicking cervical lymph node metastasis

AbstractWe herein report a rare case of benign lateral neck ectopic thyroid tissue that presentation micmicked cerivcal lymph node metastasis of follicular thyroid cancer and discuss its management pearl.

Ectopic thyroid tissue in adrenal gland – A case report and review of literature

Ectopic thyroid tissue along the line of descent of thyroid from foramen caecum along thyroglossal duct to the normal anatomic location in neck has been reported. Ectopic thyroid tissue in adrenal gland (ETTAG) is rarely encountered and very few cases have been reported in literature. The most common differential diagnosis to be considered when thyroid follicles are noted in adrenal gland are metastasis from a thyroid malignancy or a teratoma or an ectopic thyroid tissue in adrenal gland. We present a case of an adrenal incidentaloma in a young pregnant female which was diagnosed to be ectopic thyroid tissue in adrenal gland. The review of literature of similar cases of this rare embryological aberrance is discussed. To our knowledge, only 16 such cases have been documented in literature and our case is the first one from Indian subcontinent and the largest documented with respect to size.

Ectopic Mediastinal Thyroid: A Crossroad Between a Multi-Layered Endocrine Perspective and a Contemporary Approach in Thoracic Surgery

An ectopic thyroid (ET) involves numerous scenarios of detection and outcomes, while its current management is not standardised. A mediastinal ET (MET) represents a low index of suspicion. In this paper, we introduce a 47-year-old female who was accidentally identified with an MET, and a modern surgical approach was provided. An anterior mediastinal mass of 3.2 cm was found at CT upon a prior COVID-19 infection. Previous to the infection, she experienced non-specific complaints for a few months (intermittent night sweats, facial erythema, chest pressure, and dyspnoea). Also, CT identified a thymus-like mass and a left adrenal incidentaloma of 3 cm. The endocrine panel was normal, and the subject declined further investigations. She was re-admitted 12 months later: the MET had increased +1 cm (+45% volume) and was confirmed at a 99mTc pertechnetate scintigraphy. Noting the symptoms, mediastinal anatomy, and size change, the MET was removed via a minimally invasive trans-cervical approach (eutopic gland preservation) with the help of a Cooper thymectomy retractor (which also allowed for a synchronous thymus mass resection). No post-operatory complications were registered, the thyroid function remained normal, and the mentioned symptoms were remitted. A histological exam confirmed a benign MET and thymus hyperplasia, respectively. To conclude, this case pinpoints important aspects, such as the clinical picture became clear only upon thoracic surgery due to the complete remission of the complaints that initially seemed widely non-specific. The incidental MET finding was associated with a second (adrenal) incidentaloma, a scenario that might not be so rare, following multiple imaging scans amid the COVID-19 era (no common pathogenic traits have been identified so far). The co-presence of a thymus mass represented one more argument for surgery. Minimally invasive cervicotomy associated with eutopic gland conservation and the use of a Cooper thymectomy retractor highlight modern aspects in video-assisted thoracic surgery, which provided an excellent outcome, involving one of the lowest mediastinal thyroids to be removed by this specific procedure. Awareness of such unusual entities helps inform individualised, multidisciplinary decisions for optimum prognoses.

Ectopic Papillary Thyroid Cancer: About a Case

Ectopic Papillary Thyroid Cancer: About a Case

Papillary carcinoma arising from de novo ectopic thyroid tissue within thyroglossal duct cyst: A rare case report

The most common congenital anomaly of thyroglossal duct is a thyroglossal duct cyst, but carcinoma arising from a thyroglossal duct cyst is a rare phenomenon. Carcinomas involving thyroglossal duct cysts are mostly papillary carcinomas. Definitive diagnosis of carcinomas involving thyroglossal duct cysts is done through surgical excision and subsequent histopathological examination. Most carcinomas arise de novo from ectopic thyroid tissue within thyroglossal duct cysts, but the direct spread of papillary carcinomas arising from the thyroid gland can also present themselves as carcinomas involving thyroglossal duct cysts in a minority of patients. Clinical presentation in most of the patients with carcinoma of thyroglossal duct cyst is quite similar to that of the patients with histopathologically diagnosed thyroglossal duct cyst, i.e., a painless anterior midline neck swelling with cosmetic concern and no other significant symptom(s). Careful clinical examination, imaging techniques, fine needle aspiration cytology, etc., can be helpful in indicating the presence of carcinoma preoperatively. Management of patients with thyroglossal duct cyst carcinoma involves only the Sistrunk procedure in the majority of cases. However, in a minority of patients, management by Sis trunk procedure with additional total thyroidectomy (with or without dissection of lymph nodes of the neck) and adjuvant chemo and radio-ablation therapies are needed. Here, we report a case of a 17-year-old female with papillary carcinoma involving thyroglossal duct cyst who presented with a submental swelling and was eventually managed by Sis trunk procedure, total thyroidectomy, and adjuvant therapies for optical cure. Decisions for the management of her cancer were taken through multidisciplinary interactions at tumor board meetings and by judging her surgical and therapeutic needs based on her clinical, radiological, and pathological findings.

Genetic Analyses in a Cohort of Pediatric Patients with Congenital Hypothyroidism Based on Congenital Hypothyroidism Consensus Guideline

Introduction: Pathogenic variants in the genes involved in the formation of thyroid tissue and thyroid hormone secretion have been reported to cause congenital hypothyroidism (CH) in some cases. This study aimed to evaluate the clinical and genetic findings of CH cases thought to be due to genetic variants. Methods: The study included cases whose genetic analysis was performed in accordance with the Congenital Hypothyroidism: A 2020–2021 Consensus Guidelines Update Guidelines recommendations criteria and analyzed them using the next-generation sequencing panel. Results: Sixty one Turkish patients from 45 families were included in the study. The overall frequency of variant detection was 37.7% (out of 45 families, 17 had a positive mutation). Segregation was carried out for all families with positive variants. Variants in the TPO gene are the most frequently encountered, and this situation was identified in 10 families. Variants followed this in the TSHR gene in 7 families, variants in the DUOX2 gene in 5 families, and two variants in the TG and NKX2-1 genes in 2 families each, which are six novel variants. Furthermore, among the NKX2-1 cases, one had thyroid involvement only, while the other had chorea only. We did not find differences between cases with detected mutations and mutation-negative cases regarding gender, neonatal/perinatal parameters, initial thyroid function values, and thyroid morphology. Conclusion: In the current investigation, rare new variations in genes known to be related to CH were discovered, adding to the molecular genetic spectrum. When we compare the overall variant detection frequency, the selection criterion for genetic analysis based on the current guidelines is quite rational, considering the benefits and costs, on the other hand, present in new genes awaiting discovery. Also, TSHR mutations are likely to be common and may account for more than 5% of thyroid dysgenesis cases if we include nonfamilial thyroid dysgenesis.

Approach to Newborns with Elevated TSH: A Different Perspective from the International Guidelines for Iodine-Deficient Countries.

Lowering of thyroid-stimulating hormone (TSH) cutoffs in newborn screening programs has created a management dilemma by leading to more frequent detection of neonates with elevated TSH concentrations due to false-positive results, transient neonatal hyperthyrotropinemia (NHT), and milder forms of congenital hypothyroidism. Current consensus guidelines recommend starting treatment if the venous TSH level is >20 mU/l in the face of a normal free thyroxin (FT4) level, which is an arbitrary threshold for treatment decisions. In countries such as Türkiye, where transient NHT may be more common due to iodine deficiency and/or overload, putting this recommendation into daily practice may lead to unnecessary and over treatments, long-term follow-ups, and increased workload and costs. In this review, we addressed alternative approaches for infants with elevated TSH concentrations detected at newborn screening. Our management approach can be summarized as follows: Infants with mild NHT (TSH<20 mU/l) should be followed without treatment. In moderate NHT (TSH 20-30 mU/l), treatment or monitoring decisions can be made according to age, TSH trend and absolute FT4 level. Moderate cases of NHT should be treated if age at confirmatory testing is >21 days or if there is no downward trend in TSH and FT4 level is in the lower half of age-specific reference range in the first 21 days. In in-between cases of moderate NHT, thyroid ultrasound can guide treatment decision by determining mild cases of thyroid dysgenesis that require life-long treatment. Otherwise, monitoring is a reasonable option. Infants with compensated hypothyroidism (TSH>30 mU/l) and persistent hyperthyrotropinemia (>6-10 mU/l after neonatal period) should receive L-thyroxine treatment. But all treated cases of isolated TSH elevation should be closely monitored to avoid overtreatment, and re-evaluated by a trial off therapy. This alternative approach will largely eliminate unnecessary treatment of infants with transient NHT, mostly caused by iodine deficiency or excess, and will reduce workload and costs by preventing unwarranted investigation and long-term follow-up.

9365 Now You See Me: The Case Of The Ectopic Thyroid

Abstract Disclosure: S.I. Suarez: None. S.K. Majumdar: None. Introduction: Lingual thyroid refers to ectopic thyroid tissue located at the base of the tongue or within the thyroglossal tract secondary to failed descent to its usual site (1). Ninety percent of ectopic thyroid glands are found at the base of the tongue and can occur in 1 in every 100,000 patients (2, 3). Clinical presentations commonly relate to obstruction of the oropharynx, and patients may experience dysphagia or throat fullness/discomfort (1). We present a case of lingual thyroid presenting as dysphagia and progressive hypothyroidism. Case: A 38-year-old woman with a history of HLD and hypothyroidism was referred for evaluation of ectopic thyroid tissue. She presented to her provider for concerns of dysphagia, neck swelling, and excessive hair thinning/loss. She had a recent increase in levothyroxine dose from 112 to 125 mcg after a TSH of 20.4 (0.27 to 4.2 uIU/mL). Repeat tests showed a TSH of 29.4 and a free T4 level of 0.79 (0.8 to 1.7 ng/dL). She denied use of thyrotoxic medications, any radiation or surgeries to head or neck, personal or family history of autoimmune disorders. Thyroid was nonpalpable on exam. A thyroid US 5 years prior showed a 15 x 5 x 5 mm right lobe and 12 x 8 x 5 mm left lobe. CT scan of soft tissue of neck with contrast showed a 14 x 13 x 15 mm hyperintense nodular lesion midline along the anterior glossoepiglottic fold at the foramen cecum, with an 8 x 11 x 8 mm hyperintense nodular lesion at midline abutting the anterior body of the hyoid bone, and no thyroid tissue in the expected thyroid bed, findings consistent with ectopic thyroid tissue along the expected thyroglossal duct. Furthermore, an I-123 scan with SPECT confirmed the ectopic thyroid tissue. What was thought to be thyroid lobes on previous thyroid US was likely paratracheal fat. Levothyroxine was increased to 137 mcg per day with improvement at 2 months (TSH 10.4, Free T4 0.91). Adjusting levothyroxine replacement was the primary intervention, given that elevated TSH may result in hypertrophy of lingual thyroid tissue resulting in dysphagia, particularly if there is no mass or suspicion of cancer on imaging. Conclusion Hypothyroidism presenting with dysphagia in the absence of goiter, previous thyroid surgery, or detectable thyroid tissue should warrant consideration of ectopic thyroid tissue and initial therapy should be directed towards normalizing TSH in conjunction with excluding malignant causes.

6645 Paraganglioma or Benign Ectopic Thyroid Tissue?

Abstract Disclosure: J.A. Dower: None. R. MacLeod: None. B. Cardoso: None. C. Matouk: None. S. Mehra: None. G. Riccio: None. L. Williams: None. S.K. Majumdar: None. Introduction: During gestation, cells destined to form the thyroid descend through the thyroglossal duct; ectopic thyroid tissue may deposit anywhere along this route from tongue base to mediastinum (1). Less commonly, thyroid tissue can be found lateral to the duct, either alone or in association with a lymph node (2). We present a case of lateral ectopic thyroid tissue mimicking paraganglioma. Clinical Case: A healthy 32-year-old woman presented to ENT with cervical adenopathy persisting for several months after a flulike illness. FNA showed no evidence of malignancy. A neck CT with contrast ordered for further evaluation revealed a 3.2 x 2.3 x 1.5 cm enhancing mass within the right carotid space, splaying the external and internal carotid artery branches, most concerning for paraganglioma. A second, smaller lesion was noted inferiorly. Neck MRI confirmed these findings and revealed a subcentimeter T2 lesion within the right thyroid lobe. The patient was referred to endocrine for further workup. She had no symptoms of sympathetic hyperactivity and no family history suggestive of pheochromocytoma or paraganglioma. Biochemical workup was largely within normal limits: plasma metanephrines 53 pg/mL (57), normetanephrines 94 pg/mL (148), calcitonin &amp;lt;2 pg/mL, TSH 1.210 uIU/mL (0.27-4.2), FT4 1.52 ng/dL (0.8-1.7). Follow-up 24-h urine studies were also unremarkable: metanephrines 166 mcg (36-190), normetanephrines 159 mcg (35-482). Brain MRI, chest CT, and abdomen/pelvis MRI were negative for additional masses. DOTATATE PET/CT was completed to determine if the thyroid lesion was another potential paraganglioma requiring resection versus a nodule amenable to biopsy; uptake was confined to the carotid space lesions, so FNA of the thyroid nodule was considered safe. Thyroid FNA revealed FLUS with genetic testing indicating low likelihood of malignancy. The patient underwent tumor embolization followed by neck dissection with successful removal of both the larger and smaller masses identified on imaging. Frozen and permanent tissue section revealed that both masses consisted of benign thyroid tissue without associated lymphoid tissue. The patient experienced jaw pain with eating after surgery and is under consideration for Botox injection. Conclusion: Benign thyroid tissue can deposit in unexpected places, mimicking malignancy and paraganglioma, alike. Even a very thorough workup can mistake the identity of a mysterious mass; only the tissue itself can make the diagnosis.

6925 A Rare Case of Metastatic Papillary Thyroid Carcinoma Confined to Cervical Lymph Node with No Identifiable Primary Tumor In The Thyroid Gland. A Diagnostic Conundrum

Abstract Disclosure: R. Abdelmasih: None. W. Pan: None. Introduction: Papillary thyroid carcinoma (PTC) is the most common treatable thyroid cancer (TC) with very good prognosis. Metastatic PTC either in the lymph node LN or extra-nodal with no primary thyroid lesion identified is a rare phenomenon referred to as occult thyroid carcinoma (OTC). Despite its rarity, it is reported and constitute a diagnostic conundrum. herein we present a case of metastatic PTC identified in cervical lymph nodes (LN) without a primary tumor in the thyroid gland confirmed with surgical pathology. Case Presentation: A 43-year-old female with history of post-ablative hypothyroidism after treatment of toxic nodular goiter for 10 years, with no family history of thyroid cancer presented with incidentally found left 1.8 Heterogeneous hypoechoic solid nodule with lobulated borders and internal calcifications along with left-sided 0.8 LN without normal fatty hilum on Ultrasound Head and Neck. Fine needle aspiration of the left thyroid nodule and suspicious LN revealed PTC in the left LN though the thyroid nodule sample was non-diagnostic. CT of head and neck showed partially calcified thyroid nodule, Hyperattenuating 8 mm left III LN without fatty hilum, and 9 mm left II calcified LN. Patient underwent total thyroidectomy, central neck, and left lateral neck dissection. Surgical pathology showed no malignancy in thyroid gland or central LNs and 1 out 5 LN of the left neck dissection showed PTC with tumor grading of pT0 pN1b pMNA. patient underwent whole-body thyrogen-stimulated thyroid scan which showed iodine avid tissue in the thyroid bed followed by high-dose I-131 radioactive iodine ablation (RAI). Discussion: OTC refers to impalpable incidental TC less than 10 mm per the WHO. Boucek et al classify OTC into four categories, recently a fifth category was added, in which metastasis is confirmed either in regional LN or distant metastasis though thyroid tissue is confirmed to be benign per pathology and imaging evaluation, our patient falls in the fifth category. Hypothesis of this phenomenon is not well understood, one suggested explanation is missed diagnosis due to not enough sample or if lesion is less than 3 mm. another hypothesis is tumor spontaneous regression, or regression secondary to treatment that was inadequate to treat the systemic process of the tumor, which we believe our patient fits in this hypothesis, given that she underwent RAI ablation many years ago. Tumor regression is very rare and reported to be 1 in 140,000 cases. Another theory suggests that PTC can arise in ectopic thyroid tissue. This case is to shed light on a rare clinical and pathological entity to avoid missed diagnoses. Prognosis depends on the extent of metastasis, with favorable one when it is limited to regional LN and worse with distant metastasis. More cases reports are warranted to help guide further management of such cases due to the lack of available guidance in use of RAI surveillance and ablation. Presentation: 6/1/2024

7817 A Rare Case of Intrathyroidal Thyroglossal Duct Cyst Presenting as a Rapidly Expanding Left Thyroid Goiter

Abstract Disclosure: C.M. Godar: None. A.J. Spiro: None. K.F. Brown: None. M.K. Shakir: None. T.D. Hoang: None. Introduction: Thyroglossal duct cysts are the most common congenital cyst in the head and neck, found during childhood as a midline neck mass. We present a rare case of a large intrathyroidal thyroglossal duct cyst with left lateral extension in an adult patient. Case Report: A 50-year-old man with family history of familial adenomatous polyposis presented for thyroid nodule evaluation. Thyroid ultrasound for screening of thyroid cancer showed a 4.8 x 4.5 x 2.5cm mixed cystic/solid hyperechoic thyroid nodule with smooth margins in the left lower thyroid lobe. He reported no compressive symptoms. FNA with standard 27G needle was insufficient for evaluation with Bethesda I result. Attempted syringe aspiration did not produce cystic fluid for analysis. The patient returned to clinic 8 weeks later due to visible enlargement of his anterior neck and new neck pressure with swallowing. Physical exam was significant for a new, firm palpable mass over the left thyroid isthmus. Bedside ultrasound noted expansion of the previously visualized mass now extending into the thyroid isthmus. FNA was reattempted with a 25G needle, and cytologic material was again inadequate. He elected to undergo left hemithyroidectomy. Histologic sections demonstrated a 3.4cm simple squamous, non-keratinizing cyst lining overlying a thickened fibrotic wall with mixed acute and chronic inflammation surrounded by benign thyroid tissue, consistent with an intrathyroidal thyroglossal duct cyst. Discussion: The thyroglossal duct derives from epithelial tissue during embryogenesis and atrophies during weeks 8-10 of gestation. A persistent duct may lead to cyst formation in the presence of remnant epithelial tissue secretions and local neck inflammation. A thyroglossal duct cyst is usually located midline in the anterior neck. This stands in comparison to a branchial cleft cyst, which arises due to failure of atrophy of the second branchial groove during embryogenesis and forms a cyst that is usually located in the upper lateral neck compartment. Other common neck masses include lipomas, dermoid cysts, or ectopic thyroid tissue. This case highlights the rarity of intrathyroidal thyroglossal duct cyst in an adult patient and the importance of definitive diagnosis and appropriate management. Presentation: 6/2/2024

6987 Whole exome sequencing for permanent congenital hypothyroidism

Abstract Disclosure: J. Ahn: None. H. Jeong: None. Background: Guidelines on congenital hypothyroidism (CH) recommend that genetic testing should aim to improve diagnosis, treatment or prognosis. Little information is available regarding the genetic heterogeneity of CH in Koreans. We aimed to investigate the genetic etiology of permanent CH to increase the genetic diagnosis rate and find associated diseases by whole exome sequencing (WES). Methods: A total of 32 patients with permanent CH were enrolled from Endocrinology Clinic at Jeju National University Hospital and Soonchunhyang University Cheonan Hospital. WES was performed on 3billion extracted through the patient's buccal swab. Variant classification is based on the guidelines presented by the American College of Medical Genetics and Genomics (ACMG) and the Association for Molecular Pathology (AMP). Results: A total of 30 variants were identified in 20 patients. (62%). WES identified 22 variants in 6 genes (DUOX2, DUOXA2, TPO, PAX8, TG, TSHR). We detected 20 Pathogenic /Likely pathogenic of 5 genes in 15 patients (50%). The most frequently affected genes were DUOX2 (n = 10), TPO(n=4) DUOXA2 (n=3), TSHR(n=3)and PAX8 (n=2). 16 patients are monogenic and 4 patients have oligo-genic mutations. The test results of patients (n=6) with thyroid agenesis or ectopic thyroid gland were all negative. Conclusions: In patients with permanent congenital hypothyroidism, the mutation rate through the WES method is quite high. Genetic testing is useful for medication dose adjustment and genetic counseling through correlation of genotype and phenotype. Presentation: 6/1/2024

12243 The Case of a Metastatic Papillary Thyroid Cancer Presenting as an Unresectable Pelvic Mass

Abstract Disclosure: M. Tucktuck: None. Y. El Soufi: None. O.G. Adeniran: None. A.A. Gliwa: None. Background: Papillary thyroid cancer (PTC) represents around 85% of all thyroid cancers, of which 2-10% of patients will present with metastasis distant to the neck. The frequency of bone metastasis in PTC occurs in only 1-4% of patients. Studies have shown that distant and multi-organ metastasis is associated with higher mortality rates. Clinical case: A 69-year-old woman with diabetes mellitus, cerebrovascular accident, and right lower extremity deep venous thrombosis, presented with right foot and hip pain for 1 week after a mechanical fall. She had a 50 pound weight loss over a year without personal or family history of thyroid cancer or disease or radiation exposure. A soft and nontender mass in the right lower abdomen was noted during a physical exam. Imaging revealed a large heterogeneous lesion (16.3 x 13.3 x 15.5 cm) in the right bony pelvis with internal necrosis, destructing the right iliac bone, and extending into the right sacrum, acetabulum, and musculature, with mass effect on the surrounding vasculature, and enlarged lymph nodes suspicious for metastasis. Thyroid imaging showed a hypervascular hyperechoic 1.3 cm nodule within the right thyroid gland and a large 2 cm left thyroid nodule with scattered microcalcifications. Thyroid function tests were within normal limits. The patient underwent an initial ultrasound guided biopsy of the pelvic mass with indiscriminate results, and later a laparoscopic excisional biopsy of the pelvic mass showed neoplastic papillary proliferation with typical nuclear features, without necrosis or associated ovarian tissue. The immuno-histopathological profile was positive for PAX-8, TTF-1, thyroglobulin, and CK7, and the Ki-67 proliferation index was ∼20-30%. The patient was diagnosed with papillary thyroid cancer with metastasis to the pelvic bone, and was classified as stage IV, cT1bN0M1. As the pelvic mass was inoperable, the patient completed total thyroidectomy and was started on hormone replacement therapy. Subsequent thyroid pathology report was negative for papillary carcinoma. Further review of imaging did not show ectopic thyroid tissue in the neck or an ovarian pathology. Before the patient’s next visit to evaluate for struma ovarii, she passed away. Conclusion: Thyroid cancer is usually treated through thyroidectomy or lobectomy, with radioiodine (RAI) therapy as an effective treatment for differentiated cancers. Our patient, who presented with extremity pain revealing a distant metastasis, completed thyroidectomy with plans to undergo RAI therapy. Our case highlighted the importance of recognizing musculoskeletal presentations as an initial and possibly only finding of a distant metastasis. It also emphasized the utility of multidisciplinary collaboration in detecting and recognizing PTC as a primary thyroid cancer, as early management can reduce mortality and lead to more favorable outcomes. Presentation: 6/2/2024

Intratracheal Ectopic Thyroid Tissue Mimicking a Subglottic Mass in a Patient With Thyroid Follicular Carcinoma on SPECT/CT.

Intratracheal ectopic thyroid tissue is an extremely rare condition with limited cases reported in the literature. It can be asymptomatic or present with symptoms such as dysphagia, bleeding, dysphonia, dyspnea, and a sensation of a foreign body in the throat, depending on its localization. Due to its various clinical presentations, it poses a diagnostic dilemma. Herein, we aimed to present the contribution of thyroid scintigraphy and SPECT/CT to the diagnosis and management of a case with follicular carcinoma in the orthotopic thyroid gland as well as an ectopic intratracheal thyroid causing cough and airway obstruction mimicking a subglottic mass.

Ectopic thyroid follicular carcinoma in the right mandible: a case report

Ectopic thyroid follicular carcinoma in the right mandible: a case report

S4054 Endoscopic Ultrasound-Guided Fine-Needle Biopsy Unveils a Rare Mediastinal Ectopic Thyroid in an Elderly Male

S4054 Endoscopic Ultrasound-Guided Fine-Needle Biopsy Unveils a Rare Mediastinal Ectopic Thyroid in an Elderly Male

Comparative Analysis of Metastatic Thyroid Carcinoma versus Ectopic Thyroid Carcinoma in Lateral Neck Masses without Identifiable Primary Thyroid Carcinoma

Background/Objectives: Thyroid carcinoma, presenting as a lateral neck mass without an identifiable primary tumor within the thyroid, poses a diagnostic challenge. This comparative analysis aimed to explore the differences between metastatic thyroid carcinoma and ectopic thyroid carcinoma, as both present with a lateral neck mass without evidence of primary thyroid carcinoma. Methods: Searches were conducted for studies on thyroid carcinoma in the lateral neck without evidence of primary thyroid carcinoma. A total of 39 patients were identified from 32 reported studies. Results: Metastatic and ectopic thyroid carcinomas were found in 11 and 28 patients, respectively. Metastatic thyroid carcinoma is characterized by evidence of spontaneous primary tumor regression within the thyroid and commonly associated with multiple lymph node metastases in central and lateral neck compartments. Ectopic thyroid carcinoma is more commonly diagnosed in younger patients and is frequently identified in branchial cleft cysts. The coexistence of normal thyroid tissue adjacent to the ectopic thyroid carcinoma was confirmed, and patients with ectopic thyroid carcinoma exhibited significantly higher rates of second-stage thyroidectomy or neck dissection. When complete surgical excision was considered adequate, excision alone was chosen for patients with ectopic thyroid carcinoma. Conclusions: Identifying these differences is valuable for the differential diagnosis and development of treatment strategies for metastatic and ectopic thyroid carcinomas in lateral neck masses without evidence of primary thyroid tumor.

Genetic and Functional Studies of Patients with Thyroid Dyshormonogenesis and Defects in the TSH Receptor (TSHR).

Genetic defects in the TSH receptor (TSHR) can cause poor thyroid differentiation (thyroid dysgenesis) and/or thyroid malfunction (thyroid dyshormonogenesis). The phenotype spectrum is wide: from severe congenital hypothyroidism to mild hyperthyrotropinemia. Over 250 TSHR variants have been published, many uncharacterized in vitro. We aimed to genetically characterize patients with thyroid dyshormonogenesis with TSHR defects and to study in vitro the effect of the genetic variants to establish the genotype-phenotype relationship. Pediatric patients with thyroid dyshormonogenesis (160 patients, Catalan CH neonatal screening program, confirmation TSH range: 18.4-100 mIU/L), were analyzed by a high-throughput gene panel. In vitro studies measuring the TSH-dependent cAMP-response-element activation were performed. Five patients with mild or severe thyroid dyshormonogenesis presented six TSHR variants, two unpublished. Each variant showed a different in vitro functional profile that was totally or partially deleterious. Depending on the genotype, some of the variants showed partial deficiency in both genotypes, whereas others presented a different effect. In conclusion, the percentage of patients with thyroid dyshormonogenesis and candidate variants in TSHR is 3.13%. Our in vitro studies contributed to the confirmation of the pathogenicity of the variants and highlighted the importance of studying the effect of the patient's genotype for a correct diagnostic confirmation.

Ectopic thyroid adenoma diagnosed in a Senegal seabream (Diplodus bellottii, Steindachner 1882): Towards an accurate diagnosis.

Thyroid tissue in teleosts is located mainly in the pharyngeal region, usually reaching other adjacent anatomical locations. Herein, a nodular lesion located in the left operculum of a Senegal seabream (Diplodus bellottii) was surgically excised and sent for microscopical evaluation. Microscopically, the lesion presented irregular borders and consisted in columnar epithelial cells arranged in a tubulopapillary pattern, surrounding a central lumen filled with acellular, acidophilic and homogeneous, material ('colloid'). To determine the lesion's histogenesis, immunohistochemistry was performed employing antibodies for AE1/AE3, CK7, thyroglobulin and vimentin. The neoplastic cells presented low mitotic index and positive immunolabelling for CK7 and thyroglobulin. Therefore, a diagnosis of ectopic thyroid adenoma was made. Herein, the successful employment of antibodies classically used in mammals for accurate diagnosis of thyroid disorders is described. Proliferation of thyroid tissue in fish may reflect environmental and physiological imbalances, making the study and correct diagnosis of these tumours in this species important.