Ectopic thyroid tissue: anatomical, clinical, and surgical implications of a rare entity

Primary ectopic substernal thyroid cancer with trachea relapse: a case report and opinions of management

Background

Ectopic substernal thyroid is a rare symptom of thyroid disease that entirely results from the developmental defects at early stages of thyroid embryogenesis and during its descent. Cases were seldom reported as primary ectopic substernal thyroid cancer, especially those with severe local invasion and tracheal relapse.

Case Presentation

In this report, the patient presented odynophagia and a sense of progressing swallowing obstruction. She underwent total thyroidectomy and lump resection. However, she refused to use postoperative radioactive iodine or take adjuvant external-beam radiotherapy, except for thyroid hormone replacement therapy. Tracheal relapse was observed after 6 months. Tracheal stent was used to reconstruct the airway twice.

Conclusions

Trachea invasion might be a worse independent predictor of prognosis than any others and should be given particular attention. Furthermore, tracheal stent might be a palliative option for patients with tracheal relapse.

Graves' disease in a mediastinal mass presenting after total thyroidectomy for nontoxic multinodular goiter: a case report

BACKGROUND

Thyrotoxicosis after total thyroidectomy is mostly iatrogenic. Rarely, a hyperfunctional thyroid remnant or ectopic tissue may be the cause. There are few cases of Graves' disease arising from thyroid tissue located in the mediastinum and none in which Graves' disease was diagnosed only after surgery. We report the case of a patient with Graves's disease in a mediastinal thyroid mass presenting 7 years after total thyroidectomy for nontoxic goiter.

CASE PRESENTATION

A 67-year-old Caucasian woman presented with palpitations, fatigue and weight loss. She had a history of total thyroidectomy for nontoxic multinodular goiter at the age of 60 without any signs of malignancy on microscopic examination. She had been medicated with levothyroxine 100 μg/day since the surgery without follow-up. She was tachycardic, had no cervical mass or eye involvement. Her thyroid-stimulating hormone levels were suppressed (0.000 μU/mL) and her free thyroxine (3.22 ng/dL) and free triiodothyronine (8.46 pg/mL) levels increased. Neither mediastinal enlargement nor trachea deviation was found on chest roentgenogram. Levothyroxine treatment was stopped but our patient showed no improvement on free thyroxine or free triiodothyronine 10 days later. Thyroglobulin was increased to 294 mg/mL. A cervical ultrasound scan revealed no thyroid remnant. Her anti-thyroid-stimulating hormone receptor antibodies were high (19.7 U/L). Corporal scintigraphy demonstrated increased intrathoracic radioiodine uptake. A computed tomography scan confirmed a 60 × 40 mm mediastinal mass. Methimazole 10 mg/day was started. Three months later, her thyroid function was normal and she underwent surgical resection. Microscopic examination showed thyroid tissue with no signs of malignancy.

CONCLUSIONS

Although thyrotoxicosis after total thyroidectomy is mostly due to excessive supplementation, true hyperthyroidism may rarely be the cause, which should be kept in mind. The presence of thyroid tissue after total thyroidectomy in our patient may correspond to a remnant or ectopic thyroid tissue that became hyperfunctional in the presence of anti- thyroid-stimulating hormone receptor antibodies.

Prenatal Ultrasound Diagnosis of a Cyst of the Oral Cavity: An Unusual Case of Thyroglossal Duct Cyst Located on the Tongue Base

We describe a case of a lingual thyroglossal duct cyst diagnosed prenatally by ultrasound at 26 weeks of gestation. The follow-up ultrasound scans revealed no changes in the cyst measurement. Surgical treatment was performed without any complication 72 hours after delivery with good results.

LINGUAL THYROID: 35-YEAR EXPERIENCE AT A TERTIARY CARE REFERRAL CENTER

OBJECTIVE

Lingual thyroid (LT) results from a developmental abnormality due to failure of the thyroid gland to descend to its pretracheal position. Given the low incidence of this disease, standardized management recommendations are lacking. We aimed to describe our institution's experience in LT management and to suggest a practice algorithm.

METHODS

We conducted a retrospective review of LT diagnosed at Mayo Clinic, Rochester, Minnesota, between 1976 and 2010. Demographics, clinical presentation, laboratory data, treatment received, and outcomes were collected.

RESULTS

We identified 29 patients with LT. Eighty-three percent were female; age at diagnosis ranged from 2 weeks to 68 years. Almost one-third of patients were symptomatic, with the most common symptoms being cough and hoarseness. The diagnosis of LT was incidental in 9 patients (31%). Seventy-two percent of patients developed hypothyroidism. Levothyroxine was the treatment of choice, followed by thyroidectomy. Two asymptomatic euthyroid patients were followed without any intervention.

CONCLUSION

Management of patients with LT should be individualized and guided by the patient's symptoms and thyroid hormone status.

Differentiated thyroid carcinoma in lingual thyroid

The lingual thyroid is the most common form of thyroid ectopy. The ectopic tissue may display any disease affecting the thyroid, including malignancies, which have an estimated incidence of less than 1%. To date only 51 cases of lingual thyroid cancer were reported. Analogously to what observed in orthotopic thyroid, papillary carcinoma is the predominant histotype in lingual thyroid carcinoma. The higher frequency of lingual follicular thyroid carcinoma previously reported is possibly related to histological misclassification in some early reports, prior to the standardization of histological typing of differentiated thyroid carcinomas. Nonetheless, the frequency of the follicular histotype is not negligible, accounting for about one-third of the reported cases. Both natural history and prognosis of lingual thyroid carcinoma are poorly known, likely because of the rarity of the disease and the heterogeneity in the therapeutic approach. However, among the cases more recently reported, surgical excision of the mass, either alone or followed by radioiodine ablation, is the first-line approach, with only two cases treated by radioiodine alone. The nonsignificant rate of neoplastic transformation in lingual thyroid should encourage efforts to obtain a widely accepted consensus for the management of this rare condition, along with standardization of either diagnostic or therapeutic handling of malignancies arising in ectopic thyroid.

Imaging of Pediatric Neck Masses

Pediatric neck masses comprise a wide spectrum of entities, benign and malignant. The role of imaging is to characterize these lesions, in order to better determine which can be expectantly managed and which require immediate intervention. An important consideration in the pediatric population is ionizing radiation; while X-ray and CT can be useful, radiation can have harmful effects, particularly in children. In this article, we review imaging feature of common pediatric neck masses, with emphasis on radiation sparing modalities (ultrasound and MRI) when possible.

How to cite this article

Sajedi P, Shet N. Imaging of Pediatric Neck Masses. Int J Head Neck Surg 2016;7(2):89-96.

Prevalence, diagnosis and management of ectopic thyroid glands

Ectopic thyroid tissue (ETT) is an uncommon entity that may be found anywhere along the line of the obliterated thyroglossal duct, usually from the tongue to the diaphragm. We performed a retrospective analysis of patients undergoing surgical treatment for thyroid disease between January 2000 and December 2013, seeking for ETT All patients with prior neck surgery or trauma were excluded. The clinic-pathologic features, prevalence and diagnosis of the lesions were collected and analyzed. Out of 3092 included patients, 28 ETT were identified (0.9%). The anatomical site of ETT was as follows: lateral cervical in 6 (21.4%), along the thyroglossal duct in 6 (21.4%), mediastinal in 5 (17.9%), lingual in 5 (17.9%), sublingual in 3 (10.7%), and submandibular in 3 (10.7%). Histopathology revealed 27 benign lesions and 1 (3.6%) papillary carcinoma. ETT is found in less than 1% of patients receiving thyroid surgery. Diagnosis of ETT requires clinical imaging. Surgery is a prudent choice due to the potential of malignant evolution of ETT.

New insight into ectopic thyroid glands between the neck and maxillofacial region from a 42-case study

BACKGROUND

Ectopic thyroid is a rare disease. In the present study at the 9th People's Hospital in Shanghai, China, 42 patients' ectopic thyroid glands between the neck and maxillofacial region were subjected to a retrospective and transverse study based on data from 1978 to 2012 to explore the natural characteristics of ectopic thyroid.

METHODS

The patients' clinical data were collected. In addition, scintigraphy (Tc-99 m, Iodine-131), CT scan, histology and pathology were performed. The protein expression of thyroid transcription factor-1 (TTF-1), thyroglobulin (TG), calcitonin (CT), Ki-67 and parathyroid hormone (PTH) were analyzed from paraffin wax-stored specimens of ectopic thyroid tissue compared with those of orthotopic thyroid tissue.

RESULTS

There were 42 total ectopic thyroid patients, approximately 1.24 patients per year on average at our hospital. These patients were aged from 6 to 85 years old, and there were 35 females (83.3 %), seven males (16.7 %). In total, 27 of the patients had lingual thyroid (64 %); seven, sublingual thyroid (17 %); five, dual areas occupied by ectopic thyroid (12 %) and three, other types (7 %). The following conditions were also presented: nodular goiter (13 %), adenoma (8.7 %) and Hashimoto's thyroiditis (4.3 %), no malignancy and no accompanying ectopic parathyroid. TTF-1 expression was significantly higher in ectopic samples than that in orthotopic samples (P = 0.007), but CT and Ki-67 levels displayed no difference. PTH was negative in ectopic tissue.

CONCLUSION

Ectopic thyroid is a rare disease and females were more prone to the disease. The most frequent location was lingual thyroid. Nodular goiter, adenoma and Hashimoto's thyroiditis was observed as orthotopic thyroid without accompanying ectopic parathyroid. TTF-1 was highly expressed in ectopic tissue, which may be related to abnormal embryogenesis leading to the thyroid gland being in an abnormal position. The expression of calcitonin (CT) and Ki-67 was not increased, and there were no malignant cells in any sample, which could indicate that it is not easy for ectopic thyroids to become malignant between the neck and maxillofacial region.

Midline Ectopic Thyroid Mimicking as a Thyroglossal Duct Cyst

Ectopic thyroid tissue is a rare developmental abnormality. A case is reported here of ectopic thyroid tissue that presented as a midline mass, mimicking a thyroglossal duct cyst. The thyroid gland was not visualized in its normal position. This report highlights the importance of imaging in the preoperative evaluation of a midline neck mass.

Rate of thyroglossal duct remnant visualization after total thyroidectomy for differentiated thyroid carcinoma and its impact on clinical outcome of radioactive iodine (I-131) ablation

Objectives:

The rate and impact of thyroglossal duct remnant (TGDR) visualization in patients with hypothyroidism after total thyroidectomy for differentiated thyroid carcinoma (DTC) have not yet been fully determined. The aim of this study was to assess the rate of TGDR visualization in post total thyroidectomy whole body scan (WBS) for DTC and to evaluate its impact on the outcome of I-131 ablation.

Methods:

A total of 60 consecutive DTC patients (51 papillary thyroid Ca., and 9 Follicular thyroid Ca.), underwent total thyroidectomy, followed by WBS (using I-131 in 28 patients and I-123 in 32 patients), neck ultrasound (US), thyroglobulin (Tg) and Tg anti-bodies (TgAb) assay after 40 days and subsequent I-131 ablation. At 6 months later follow-up I-131 WBS, neck U/S, Tg and TgAb were performed following suspension of L-thyroxine for 1-month (thyroid stimulating hormone [TSH] >30 μIU/ml) in 53 patients and following recombinant human TSH stimulation in seven patients.

Results:

Of the studied 60 patients, 19/60 (31.7%) had a linear or focal radioactivity at the superior midline of the neck, suggesting TGDR (Group 1), and 41/60 (68.3%) had no uptake to suggest TGDR (Group 2). No significant difference regarding age, gender and histopathology between both groups. Neck US showed no evidence of thyroid tissue in the superior midline of the neck in both groups, and only a small or no residual thyroid tissue in patients of Group 1. There was a significant successful I-131 ablation rate among patients of group 1 compared to group 2 (79% in Group 1 vs. 41.5% in Group 2) (P = 0.007).

Conclusions:

Thyroglossal duct remnant visualization on WBS of hypothyroid subjects after total thyroidectomy suggests presence of only a small or no residual functioning thyroid tissue at the thyroid bed and can predict a good response to I-131 ablation.

Ectopic thyroid tissue in the adrenal gland: report of a case

Foci of ectopic thyroid tissue are uncommon. Most sites of thyroid ectopia are confined to the neck region. The presence of ectopic thyroid tissue outside the migration pathway of the primitive thyroid in other locations is exceptional. Given that any disease of the thyroid gland may also affect ectopic thyroid tissue, pathologists has to recognize benign or malignant conditions that may develop in the ectopic focus. We present the case of a 32-year-old woman with ectopic thyroid parenchyma in the adrenal gland. Clinically, postoperative thyroid ultrasound echography and computed tomography scans did not reveal any thyroid tumor. The ectopic tissue was a cyst bordered by mature follicular thyroid structures and was histologically benign, without the molecular alterations associated with malignant tumors of follicular cell derivation (BRAFV600E, N-RAS, H-RAS, K-RAS). Review of the literature reveals that adrenal ectopic thyroid tissue is nearly always cystic and has distinctive pathologic features.

Conservative management for lingual thyroid ectopic

Lingual thyroid gland is a rare clinical entity. The presence of an ectopic thyroid gland located at the base of the tongue may be presented with symptoms like dysphagia, dysphonia, and upper airway obstruction. We are introducing a case of an 8-year-old girl who had lingual thyroid that presented dysphagia and foreign body sensation in the throat. The diagnostic was reached with clinical examination, thyroid scintigraphy with Tc^99m and ultrasound. A laryngoscopy was performed which confirmed a spherical mass at base of tongue. Investigation should include thyroid function tests. In this case we observed subclinical hypothyroidism. There are different types of surgical approaches for the treatment of this condition; however, the treatment with Levothyroxine Sodium allowed the stabilization of TSH levels and clinical improvement of symptoms in a follow-up of 2 years.

Pathology of thyroglossal duct: an institutional experience

Thyroglossal duct (TGD) is a developmental anomaly in which a remnant of the thyroid anlage is left in the neck during its descent from the foramen cecum of tongue to final pretracheal position. A persistent duct can lead to thyroglossal duct cyst (TGDC). Histologically, TGDC contains an epithelial lining of squamous or pseudostratified ciliated columnar epithelium and ectopic thyroid gland tissue in the duct wall. TGD-associated malignancy is rare, and the majority is papillary thyroid carcinoma (PTC). A total of 242 patients with a diagnosis of TGD-associated lesions were identified in our institute. Two hundred and seventeen cases were diagnosed as TGDC. Sixty-eight of 217 (31.3 %) cases of TGDC had ectopic thyroid tissue in the cystic wall. Thirty-nine cases had preoperative fine needle aspiration (FNA). Of these cases, 37 of 39 (94.9 %) demonstrated macrophages and 19 (48.7 %) also showed cells of squamous and/or columnar epithelial lining. Only two cases showed rare thyroid follicular cells. Thyroid carcinoma was identified in 18 of 242 (7.4 %) cases. All cases were diagnosed as PTC including 12 cases of classic PTC (66.7 %), 3 cases of follicular variant (16.7 %), 2 cases of tall cell variant (11.1 %), and 1 case of classic PTC with focal tall cell features (5.6 %). Nine cases had TGD component (either epithelial lining cysts or ectopic thyroid tissue). Ten patients also underwent total thyroidectomy (67 %). Of these patients, four had no tumor and one had an incidental medullary carcinoma. Five of 10 (50 %) cases had incidental PTC with a size range of 0.1-0.3 cm. Five patients had follow-up by imaging studies; no suspicious or nodular lesions were found in the thyroid. In conclusion, we report an institutional case cohort of 242 patients with TGD-associated lesions, including 217 TGDC and 18 cases of PTC. Only seven cases fulfilled the diagnostic criteria of TGD-associated PTC, i.e., the presence of components of TGD and a normal thyroid. In the remaining 11 cases, we could not differentiate with certainty between pyramidal primary thyroid PTC/Delphian node metastasis or TGD-associated PTC.

Acute neonatal respiratory distress caused by a lingual thyroid: the role of nasendoscopy and medical treatment

BACKGROUND

A lingual thyroid is a known cause of oropharyngeal obstruction in the neonate. It can be asymptomatic, or present as stridor, dysphonia, dysphagia or dyspnoea with faltering growth. The therapeutic options include surgical resection.

CASE REPORT

A 6-day-old female neonate, born at 36 weeks gestation, presented with stridulous breathing and poor feeding. Although the cause was initially thought to be laryngomalacia, nasendoscopy revealed a lingual thyroid. The baby had deranged thyroid function, as detected on neonatal screening, but this result was not available until a later date. Despite being symptomatic, the patient was managed medically; thyroxine therapy was associated with resolution of the respiratory symptoms.

CONCLUSION

Nasendoscopy provides valuable information about an ectopic thyroid gland. Thyroid replacement therapy may help to suppress the size of the ectopic gland and ultimately prevent an unnecessary surgical procedure.

Imaging of ectopic thyroid tissue and thyroglossal duct cysts

When a child or young adult presents with a mass in the anterior portion of the neck, diagnostic considerations include a thyroglossal duct cyst and ectopic thyroid tissue. These entities are often suspected clinically, and imaging provides an opportunity to evaluate the extent, confirm the diagnosis, and evaluate for complications. Imaging characteristics of a thyroglossal duct cyst as a simple cyst and of ectopic thyroid tissue as a hyperattenuating soft-tissue mass can help identify these lesions at computed tomography (CT); however, intrinsic magnetic resonance, CT, and ultrasonographic imaging characteristics alone cannot be used to confirm the diagnosis. Rather, knowledge of the typical course of the thyroid primordium during embryologic development is essential to understand the variant locations along this path where thyroid tissue can be found. The migration of thyroid primordium begins at the foramen cecum at the base of the tongue and then loops around the hyoid bone anteriorly and inferiorly and descends anteriorly to the thyrohyoid membrane into the orthotopic location in the infrahyoid portion of the neck. Thyroid ectopia is categorized into one of four typical locations with respect to this embryologic course: (a) the base of the tongue, (b) adjacent to the hyoid bone, (c) the midline infrahyoid portion of the neck, and, rarely, (d) the lateral part of the neck. The differential diagnosis includes metastatic thyroid carcinoma, branchial cleft cyst, lymphatic malformation, abscess, saccular cyst, epidermoid cyst, and squamous cell carcinoma. The relationship of a mass to landmarks such as the foramen cecum, hyoid bone, strap muscles, thyrohyoid membrane, and thyroid cartilage can help differentiate a thyroglossal duct cyst and ectopic thyroid tissue from other anterior neck masses when the embryologic thyroid course is considered.

Agenesis and not ectopia is common in North Indian children with thyroid dysgenesis

CONTEXT

Ectopic Thyroid Gland (ETG) is known to be the most common form of thyroid dysgenesis in children with permanent congenital hypothyroidism (CH). Recent reports indicate that agenesis or hypoplasia of thyroid gland may be commoner as compared to ETG in thyroid dysgenesis (TD). There is limited information available on the proportion of different variants of TD in Indian children.

AIM

To characterize the different TD variants in a cohort of North Indian children with TD.

SETTINGS AND DESIGN

Endocrinology Unit of a large Multispecialty Pediatrics Center located in North India. Retrospective review of clinical records of children with CH due to TD diagnosed between April 2004 and March 2014.

RESULTS

Diagnoses of TD in 94 children (48 boys and 46 girls) were based on combined scanning with high-resolution ultrasonography, and technetium-99m pertechnetate thyroid scintigraphy. Thyroid agenesis, ectopia and hypoplasia were diagnosed in 74 (78.7%), 14 (14.8%) and 6 (6.4%) patients respectively. The mean initial serum total T4 and thyroid stimulating hormone concentrations at diagnosis were 3.03 ± 2.88 μg/dL (range 0.01-8.9) and 284.52 ± 300.67 mIU/L (range 10.03-1159.0) respectively. Patients with ETG were older at the time of diagnosis as compared to patients with hypoplasia or ectopia. The mean duration of follow-up was 3.7 ± 2.85 years (range 3 months-10 years).

CONCLUSIONS

Thyroid agenesis was the most common form of TD in our children with permanent CH. Hypoplasia and ectopia were uncommon. Female preponderance, noted in many previous reports, was not seen in our patients with TD.

Radioactive iodine-131 therapy in the management of ectopic thyroid tissue

The occurrence of ectopic lingual thyroid tissue was first reported over 100 years ago. We report an unusual presentation of ectopic thyroid tissue occurring in the submental area. A 27-year-old female presented to the Sultan Qaboos University Hospital in Muscat, Oman, in October 2011 with an 8 × 6 cm mass which caused difficulty in talking and a feeling of heaviness in the jaw. She was clinically and biochemically euthyroid upon presentation. The clinical diagnosis was confirmed by a technetium(-99m) thyroid scan, magnetic resonance imaging and fine needle aspiration. A single dose of 976 megabecquerels of radioactive iodine-131 resulted in hypothyroidism after three months and the complete disappearance of the swelling and associated symptoms. At a two-year follow-up, the patient was healthy and continuing lifelong replacement therapy with thyroxine.

Ectopic thyroid mass in the left lateral neck and anterior mediastinum: a case report

Introduction

Ectopic thyroid is characterized by the presence of thyroid tissue in a site other than in its usual pretracheal region. It is a rare condition among the thyroid diseases. Dural ectopic thyroid present in the cervical and anterior mediastinal has not been reported.

Case presentation

A 45-year-old Chinese woman presented with a nonfunctional ectopic thyroid located both in the cervical and anterior mediastinum. The ectopic thyroid was removed under video-assisted thoracoscopic surgery using a transverse neck incision and her postoperative period has been uneventful thus far.

Conclusions

Ectopic thyroid is a rare condition among the thyroid diseases, and its location in the anterior mediastinum is even more uncommon. Less than 15 cases have been reported in the last four decades. This is the first case of ectopic thyroid to appear in both the cervical and anterior mediastinum at same time. Masses in the anterior mediastinal are usually thymoma, lymphoma, pheochromocytoma and germ cell tumors. Ectopic thyroid in this area is quite rare so this case enhances our understanding of the diagnosis of mediastinal masses.

Radionuclide imaging of dual ectopic thyroid in a preadolescent girl

Ectopic thyroid is a congenital defect in which the thyroid gland is located away from the usual pretracheal location. Dual ectopic thyroid, which consists of two foci of thyroid tissue, is very rare. In this case dual ectopic thyroid with subclinical hypothyroidism in a 10-year-old-girl was reported. The absence of the thyroid gland in the pretracheal location was revealed by ultrasonography (USG). Two foci of ectopic thyroid tissue located at the base of the tongue and infrahyoid region were determined by Technetium-99m pertechnetate thyroid scintigraphy. It can be concluded that if the thyroid gland is not visible by USG, ectopic thyroid tissue should be evaluated with scintigraphy.

Ectopic thyroid papillary carcinoma of nasopharynx associated with adenoid hypertrophy: an unusual presentation

Ectopic thyroid tissue of nasopharynx is an uncommon phenomenon and papillary thyroid carcinoma arising from the tissue is extremely rare. The authors report a rare case of 16-year-old girl with papillary thyroid carcinoma of nasopharynx. Clinicians were ever confused by adenoid hypertrophy and solved the diagnostic dilemma by adequate examinations. In the case, we mainly emphasize that surgeons should be aware of and actively consider such a possibility of ectopic papillary thyroid carcinoma of nasopharynx in children and adolescents with long-term nasal obstruction, even if thyroid carcinoma is a rare tumor.

Right ventricular mass: intracardiac ectopic thyroid tissue: a case report

Ectopic thyroid tissue is a result of abnormal migration of thyroid tissue during the embryonic state. Most of these rare cases, almost 90% of them, are located in the base of the tongue and a minority of them is located anteriorly near the hyoid bone area. Below we report the case of a young patient with an intracardiac mass first diagnosed with three-dimensional echocardiography and afterward successfully treated surgically. Once a careful histological examination has revealed a follicular adenoma, the prognosis is good especially if successful surgical excision is part of the management.

Papillary carcinoma in median aberrant thyroid (ectopic) - case report

Median ectopic thyroid may be encountered anywhere from the foramen caecum to the diaphragm. Non lingual median aberrant thyroid (incomplete descent) usually found in the infrahyoid region and malignant transformation in this ectopic thyroid tissue is very rare. We report an extremely rare case of papillary carcinoma in non lingual median aberrant thyroid in a 25-year-old female. The differentiation between a carcinoma arising in the median ectopic thyroid tissue and a metastatic papillary carcinoma from an occult primary in the main thyroid gland is also discussed.

Microfollicular adenoma of ectopic thyroid gland masquerading as salivary gland tumor - a diagnostic and therapeutic challenge: a case report

Introduction

Ectopic thyroid tissue may appear in any location along the trajectory of the thyroglossal duct from the foramen cecum to the mediastinum. Rarely, there is incomplete descent of the gland where the final resting point may be high resulting in sublingual ectopic thyroid tissue. Ectopic thyroid tissue carries a low risk of malignancy. Most recently reported neoplasms in ectopic thyroid tissue have been papillary carcinoma of thyroid. Individual case reports of clear cell type of follicular adenoma within the ectopic thyroid tissue have been described in the literature.

Case presentation

We present a rare case of microfollicular follicular adenoma in an ectopic sublingual thyroid tissue presenting as submental swelling in a euthyroid 24-year-old Dravidian woman.

Conclusion

Findings in this case emphasize that when confronted with a submental/sublingual mass lesion, the evaluation of thyroid function tests and ultrasonography of the neck should be included in a pre-operative workup.

The prevalence of thyroglossal tract thyroid tissue on SPECT/CT following (131) I ablation therapy after total thyroidectomy for thyroid cancer

OBJECTIVE

To determine the prevalence of thyroglossal tract thyroid tissue on SPECT/CT and to assess the contribution of this tissue to total neck radioactive iodine (RAI) activity in patients given (131) I ablation therapy after total thyroidectomy for thyroid cancer.

PATIENTS AND METHODS

Eighty-three consecutive patients with thyroid cancer treated with total thyroidectomy underwent whole-body planar and SPECT/CT imaging of the neck following initial RAI ablation. On SPECT/CT, thyroglossal tract thyroid tissue was defined as RAI in the anterior neck, superior to the thyroid bed in close proximity to the midline without evidence of localization to lymph nodes. Quantification was performed using region of interest analysis on planar imaging following localization on SPECT/CT. SPECT/CT, and planar images were classified by two reviewers as positive, negative or equivocal with interobserver agreement quantified using a Kappa score. Disagreement was resolved using a third reviewer.

RESULTS

Thyroglossal tract thyroid tissue was present in 39/83 (47%; 95%CI: 36-58%) patients on SPECT/CT. In these 39 patients, this tissue contributed to a significant amount of total neck activity (median = 50%; IQR 19-74%). Interobserver agreement for the presence of thyroglossal tract thyroid tissue was substantial on SPECT/CT (Kappa = 0.73) and fair on planar imaging (Kappa = 0.31).

CONCLUSION

Thyroglossal tract thyroid tissue was present in one half of our study population and contributed to a significant amount of total neck RAI activity. Given the high prevalence of this tissue, our results suggest that total neck RAI activity on planar imaging may not be suitable to assess the completeness of thyroid bed surgery.

Clinical features and treatment outcomes of 41 dogs with sublingual ectopic thyroid neoplasia

Background

Thyroid neoplasia is common in dogs, but there are few reports of dogs with ectopic, sublingual thyroid tumors.

Objectives

To describe clinical features and outcomes of dogs with ectopic, sublingual thyroid neoplasia.

Animals

Five hundred and forty‐four dogs with thyroid neoplasia.

Methods

This retrospective study reviewed the medical records of dogs referred for thyroid neoplasia between 1995 and 2013. Data extracted included signalment, extent of thyroid disease (eutopic or ectopic; metastasis), serum thyroxine (T₄) concentration, treatment, and survival.

Results

Of 544 dogs with thyroid neoplasia, 41 (7.5%) dogs had ectopic sublingual thyroid tumors. The clinical features of these 41 dogs were similar to the cohort group of 503 dogs with eutopic or ectopic mediastinal thyroid tumors, but dogs with sublingual tumors were younger and less likely to have metastatic disease (15% versus 30%, P < .05). Of the 41 dogs, 28 received treatment: 21 with surgery (which included partial hyoidectomy in 13), 7 with radioiodine alone, and 13 with surgery followed by administration of radioiodine. Overall median survival was 562 days (range, 1‐1,850 days).

Conclusions and Clinical Importance

When compared with eutopic thyroid carcinomas, ectopic sublingual thyroid tumors generally have a less aggressive biologic behavior. Many dogs have prolonged survival, even without treatment, although death because of local tumor invasiveness or metastasis can develop in some dogs. Surgical thyroidectomy, including partial hyoidectomy, is generally effective for control of local disease. Administration of radioiodine, alone or in combination with surgical treatment, is recommended for multifocal disease or metastasis.

Morphological, diagnostic and surgical features of ectopic thyroid gland: a review of literature

Ectopic thyroid tissue remains a rare developmental abnormality involving defective or aberrant embryogenesis of the thyroid gland during its passage from the floor of the primitive foregut to its usual final position in pre-tracheal region of the neck. Its specific prevalence accounts about 1 case per 100.000-300.000 persons and one in 4.000-8.000 patients with thyroid disease show this condition. The cause of this defect is not fully known. Despite genetic factors have been associated with thyroid gland morphogenesis and differentiation, just recently some mutation has been associated with human thyroid ectopy. Lingual region in the most common site of thyroid ectopy but ectopic thyroid tissue were found in other head and neck locations. Nevertheless, aberrant ectopic thyroid tissue has been found in other places distant from the neck region. Ectopic tissue is affected by different pathological changes that occur in the normal eutopic thyroid. Patients may present insidiously or as an emergency. Diagnostic management of thyroid ectopy is performed by radionuclide thyroid imaging, ultrasonography, CT scan, MRI, biopsy and thyroid function tests. Asymptomatic euthyroid patients with ectopic thyroid do not usually require therapy but are kept under observation. For those with symptoms, treatment depends on size of the gland, nature of symptoms, thyroid function status and histological findings. Surgical excision is often required as treatment for this condition.

Pitfalls in sonographic evaluation of thyroid abnormalities

Ultrasound of the thyroid has become increasingly common, with evaluation of thyroid nodules representing the main indication for its use. While detection of thyroid nodules with modern high-resolution sonographic equipment is generally not a challenge, pitfalls may occur by which normal structures or pathology in neighboring organs are mistaken for thyroid nodules. Numerous reports in the literature describe various sonographic features of nodules in an attempt to stratify lesions into benign or malignant categories. While neither nodule size nor number is reliable, echogenicity, microcalcifcation, shape, and composition have been reported to be helpful in classifying thyroid nodules. No single feature should be used in isolation, and consensus guidelines have been established as to when fine-needle aspiration is indicated. Pitfalls remain in the evaluation of thyroid nodules demonstrating atypical features, such as cystic papillary carcinomas. Focal presentation of typically diffuse processes, such as Graves' disease and Hashimoto thyroiditis, may mimic malignant nodules, but carcinomas occur in these settings as well as in a background of normal thyroid parenchyma. Finally, because ultrasound is commonly used for surveillance of patients with thyroid carcinoma after thyroidectomy, sonographers should be familiar with the ultrasound appearance of disease recurrence and its mimics.

Whole-exome sequencing: opportunities in pediatric endocrinology

Pediatric endocrinology services see a wide variety of patients with diverse clinical symptoms, including disorders of growth, metabolism, bone and sexual development. Molecular diagnosis plays an important role in this branch of medicine. Traditional PCR-based Sanger sequencing is a mainstay format for molecular testing in pediatric cases despite its relatively high cost, but the large number of gene defects associated with the various endocrine disorders renders gene-by-gene testing increasingly unattractive. Using new high-throughput sequencing technologies, whole genomes, whole exomes or candidate-gene panels (targeted gene sequencing) can now be cost-effectively sequenced for endocrine patients. Based on our own recent experiences with exome sequencing in a research context, we describe the general clinical ascertainment of relevant pediatric endocrine patients, compare different formats for next-generation sequencing and provide examples. Our view is that protocols involving next-generation sequencing should now be considered as an appropriate component of routine clinical diagnosis for relevant patients.

Hashimoto's thyroiditis: an accidental discovery of a lingual thyroid in a 7-year-old child

An ectopic thyroid located at the base of the tongue is a rare entity, resulting from early developmental defects of thyroid gland embryogenesis during its descent from the foramen caecum to its normal eutopic pretracheal site. This condition is the main cause of congenital primary hypothyroidism, even though signs and symptoms of thyroid dysfunction may also appear later in childhood. Lingual thyroid may sometimes present with symptoms of respiratory obstruction or feeding difficulties. We illustrate the case of a 7-year-old girl with subclinical hypothyroidism due to Hashimoto's thyroiditis arising in a lingual thyroid. She had never suffered from upper airway obstructive symptoms, but did refer a 3-month history of cough. Rapid normalisation of thyroid-stimulating hormone levels and termination of the cough were attained when the L-thyroxine treatment started. After 6 months a significant reduction of lingual thyroid size was also noted. The diagnostic procedures and therapeutic options in childhood are discussed.

Coexistence of non-functional ectopic thyroid tissue and a normal thyroid: A case report

The aim of this study was to report a rare case of non-functional ectopic thyroid tissue in the neck with a coexisting normal thyroid. A 36-year-old female presented with a mass in the anterior neck. The thyroid function of the patient was normal. Ultrasonography and computed tomography (CT) revealed a normal thyroid gland and a solid mass in the middle lower neck. Scintigraphy showed a normal thyroid and the mass did show any uptake of ^99mTcO_4^- . The patient underwent en bloc resection. During surgery, the mass was observed to be well encapsulated and completely separated from the thyroid gland. Histology revealed it as ectopic thyroid tissue. The patient had an uneventful recovery.

Right ventricular outflow tract tumour: an unsuspected intracardiac ectopic thyroid mass

Ectopic thyroid is a rare embryogenic anomaly that occurs during its migration from foramen caecum to its pretracheal position. An intracardiac ectopic location is even rarer and found most commonly in the right ventricular outflow tract in sporadic reports. While surgery in symptomatic patients seems appropriate, resection of non-neoplastic ectopic tissue remains a clinical equipoise. Its occurrence is often unsuspected by clinicians, but its possibility should be considered due to its typical location in the right ventricular outflow tract. Unlike true neoplastic intracardiac tumour which mandates surgical resection, both surgical and non-surgical approach may be considered for an intracardiac ectopic thyroid mass.

Computed tomographic features of basihyoid ectopic thyroid carcinoma in dogs

Eight dogs with a firm, nonpainful swelling in the ventral laryngeal region and with a final diagnosis of ectopic thyroid carcinoma were investigated by Computed Tomography (CT) at six different institutions. Computed Tomography findings were reviewed, focusing on lesion volume, shape, margins, relationship with surrounding structures and adjacent vessels, attenuation characteristics, and presence of metastases. Ectopic thyroid carcinomas were seen as oval-to-bilobed masses centered on the basihyoid bone with associated bone lysis, highly vascularized capsules with central poorly contrast enhancing areas. In all cases there was laryngeal wall infiltration, in two dogs invasion of the laryngeal lumen and in one case invasion of the ventral muscular and subcutaneous plane. Metastases were found in retropharyngeal lymph nodes (three cases) and in the lung (two cases). Ectopic thyroid carcinoma should be considered in the differential diagnosis when a mass in the basihyoid region is present. Described CT features may be typical for ectopic thyroid neoplasia and could be used to help decide the therapeutic plan.

Papillary thyroid carcinoma in a lateral neck cyst: primary of ectopic thyroid tissue versus cystic metastasis

Objective:

To review the diagnosis of primary papillary carcinoma of ectopic thyroid tissue within branchial cleft cysts, and to discuss the diagnostic challenge of differentiating this condition from metastatic disease when an occult microcarcinoma is found in the thyroid gland.

Methods:

These comprise a case report and a literature review. We present the case of a 75-year-old woman with papillary thyroid carcinoma within the wall of a recurrent, 15 cm, lateral neck cyst.

Results:

Histological examination of the patient's thyroid gland found a 0.5 mm papillary thyroid microcarcinoma.

Conclusion:

Our differential diagnosis was primary papillary carcinoma arising from ectopic thyroid tissue, or metastatic cystic degeneration of a lateral lymph node. We make an argument for the former.

Ectopic intrapulmonary thyroid: a case report

An ectopic thyroid is caused by abnormalities in migration of the thyroid during development and rarely occurs in the thoracic cavity or the abdominal cavity. We report the case of a 64-year-old female who had abnormal findings from a thyroid hormone test during follow-up after thyroid cancer surgery. Based on the radioisotope diagnostic test, an ectopic thyroid inside the thoracic cavity was suspected. Through surgical treatment, the patient was diagnosed with ectopic intrapulmonary thyroid. Ectopic intrapulmonary thyroid is reported to be very rare and the case is described along with a literature review.

Incidental focal uptake in oropharynx due to lingual thyroid on diagnostic 131I whole-body scan after total thyroidectomy

After total thyroidectomy for papillary thyroid carcinoma, a 37-year-old woman underwent a 2-mCi (131)I whole-body scan which demonstrated focal uptake in the anterior neck and in the oropharynx. Preoperative contrast-enhanced neck computed tomography demonstrated a small enhancing nodule typical for ectopic thyroid at the tongue base. She was then treated with 150 mCi (131)I. Small asymptomatic lingual thyroid remnants typically do not affect high-dose (131)I therapy.

Thyroid papillary carcinoma arising in ectopic thyroid tissue within a branchial cleft cyst

Ectopic thyroid tissue comprises a rare clinical entity which can clinically manifest with the whole spectrum of thyroid disorders, including thyroid malignancy. Thyroid carcinoma arising in ectopic thyroid tissue is extremely rare, with only a few cases described in the literature so far. We present a very unusual case of a primary papillary thyroid carcinoma arising in a left lateral branchial cyst, describing our diagnostic and therapeutic approach for this uncommon clinical entity. This is the first case where recombinant thyrotropin was used along with radioiodine treatment in primary ectopic thyroid cancer.

Mucoepidermoid carcinoma of the tongue base mimicking an ectopic thyroid

A 69-year-old woman with mucoepidermoid carcinoma (MEC) of the tongue base came under our observation complaining of repeated episodes of haemoptysis. Mucoepidermoid carcinoma of the tongue base gives rise to a rather vague and aspecific symptomatology. Early symptoms include foreign body sensation in the oral cavity, undefined paraesthesia, and sialorrhoea. With the progression of disease, dysphagia, otalgia, and painful swallowing are usually referred. We report a case of mucoepidermoid carcinoma of the tongue base mimicking an ectopic thyroid.

Lingual thyroid: diagnosis using a hybrid of single photon emission computed tomography and standard computed tomography

AIM

To present a rare case of lingual thyroid detected using a hybrid of single photon emission computed tomography and standard computed tomography in a young woman with hypothyroidism.

MATERIALS AND METHODS

A 29-year-old woman was screened for autoimmune thyroid disorders in early pregnancy, and found to have subclinical hypothyroidism. No thyroid tissue was found in the anterior neck upon ultrasonography, raising suspicions of an ectopic thyroid. The patient was treated with levothyroxine throughout the remainder of her pregnancy, and developed postpartum thyroiditis requiring an increase in levothyroxine dosage. Whole-body scintigraphy and zoomed static head and neck scintigraphy were performed. Abnormal 99mTc-pertechnetate uptake was observed in the oral region, whereas no uptake was found in the usual thyroid location. Hybrid imaging using single photon emission computed tomography and standard computed tomography was performed to improve three-dimensional representation of the area of increased activity.

RESULTS

The latter imaging modality detected ectopic thyroid tissue in the tongue.

CONCLUSION

Whole body 99mTc-pertechnetate scintigraphy and a hybrid of single photon emission computed tomography and standard computed tomography are effective imaging modalities for the investigation of ectopic thyroid tissue. The latter modality is particularly recommended, as it allows more precise spatial visualisation of increased isotope uptake activity in the head and neck.

Mechanisms of thyroid development and dysgenesis: an analysis based on developmental stages and concurrent embryonic anatomy

Thyroid dysgenesis is the most common cause of congenital hypothyroidism that affects 1 in 3000 newborns. Although a number of pathogenetic mutations in thyroid developmental genes have been identified, the molecular mechanism of disease is unknown in most cases. This chapter summarizes the current knowledge of normal thyroid development and puts the different developmental stages in perspective, from the time of foregut endoderm patterning to the final shaping of pharyngeal anatomy, for understanding how specific malformations may arise. At the cellular level, we will also discuss fate determination of follicular and C-cell progenitors and their subsequent embryonic growth, migration, and differentiation as the different thyroid primordia evolve and merge to establish the final size and shape of the gland.