Lingual thyroid and lingual thyroglossal tract remnants. A clinical and histopathologic study with review of the literature

The clinicopathological features, treatment outcomes and follow-up results of 47 ectopic thyroid gland cases: a single-center retrospective study

Background

Ectopic thyroid gland (ETG) is an uncommon clinical condition, presenting various challenges and limitations in its regulate diagnosis and treatment currently. This study aims to enhance our understanding of ETG and improve the strategies for its diagnosis and treatment.

Methods

The retrospective single-center study was conducted, encompassing clinical data from ETG patients screened at our institution between 2013 and 2022. Patients were categorized based on the location of the disease, and follow-ups were performed on each.

Results

This study included a total of 47 patients who were confirmed to hav confirmed to have ETG. Among them, we found 29 cases of accessory thyroid and 18 cases of aberrant thyroid. Furthermore, 42 cases exhibited the single ETG, while 5 cases displayed the double ETG. The distribution of the ETG was as follows: 20 were lingual, 10 were submandibular, 10 were lateral cervical, 4 were thoracic mediastinal, 1 was esophageal, and 7 were ovarian. Of these cases, 22 patients underwent surgery, 18 received thyroid hormone replacement therapy, and 7 were placed under observation. All patients were followed up for 59.4 (12-117) months. No significant abnormalities were detected at the conclusion of the follow-up period.

Conclusion

ETG is frequently observed in the head and neck, particularly in lingual. Accessory thyroid glands are commonly reported, with most cases being single ETG. Notably, these glands usually do not manifest specific clinical symptoms. Therefore, the appropriate and comprehensive examinations during the initial diagnosis are crucial to avoid misdiagnosis. Treatment should be individualized, and long-term follow-up is essential for managing ETG effectively.

[Ectopic thyroid gland: clinical features and diagnostics in children]

BACKGROUND

BACKGROUND: The frequency of ectopia of thyroid gland among all types of dysgenesis varies from 30 to 70%, its most common localization is the root of the tongue. Otorhinolaryngologists, oncologists, pediatricians can take lingual ectopia for hypertrophy of the lingual tonsil or fibroma of the tongue root, which leads to unreasonable surgical treatment. Thyroid scintigraphy plays a key role in the diagnosis of ectopia.

AIM

AIM: To assess the etiological structure of congenital hypothyroidism (CH) and demonstrate the clinical course in patients with ectopic thyroid tissue in the root of the tongue.

MATERIALS AND METHODS

MATERIALS AND METHODS: A group of patients with CH was examined. All patients underwent neck ultrasound and radionuclide imaging. The examination was carried out against the background of the abolition of hormone replacement therapy for 14 days or before its initiation. Patients with ectopia in the root of the tongue underwent videofibrolaryngoscopy. Some patients underwent a genetic study with using genes panel of a panel of candidate genes responsible for the development of CH using the NGS method. The molecular genetic study was conducted to some patients, next-generation sequencing with the genes panel.

RESULTS

RESULTS: The study included 73 patients with primary CH aged from 2 weeks to 17.3 years: 69 children were diagnosed based on the results of neonatal screening, 4 children with thyroid ectopia were first examined older than 6 years. The median age of patients at the time of the examination was 6.9 years [4.8; 10.0]. By data of ultrasound aplasia was diagnosed in 47.9% of patients, one child had hemiagenesis and ectopic thyroid tissue of various localization was detected in 26.0% of  children. In 24.7% of children thyroid tissue was found in a typical location. Scintigraphy confirmed thyroid aplasia in 65.7% of children. Examination revealed various variants of ectopically located thyroid tissue in 31 children (42.4%): thyroid ectopia in the root of the tongue in 25 children (80.6%), ectopia in the sublingual region in 5 children (16.2%), double ectopia was detected in 1 child. The median level of TSH in newborns with ectopic thyroid gland was 124 IU/ml and was significantly lower than in children with aplasia — 219 IU/ml, p<0.05. On the other side the level of TG in children with ectopia was significantly higher than in children with aplasia — 37.12 ng/ml versus 0.82 ng/ml, p><0.05. CONCLUSION: Combination of two methods is the best diagnostic approach to determine the etiology of CH — ultrasound and scintigraphy studies compensates deficiencies of each other. Our study demonstrates the importance of scintigraphy in children with CH and patients with the formation of the root of the tongue and the anterior surface of the neck in order to avoid unnecessary removal of the thyroid gland. In case of confirmation of thyroid ectopia in the root of the tongue and in the absence of symptoms of obstruction or bleeding, it is recommended to refer the patient to an endocrinologist for conservative treatment. ><0.05. On the other side the level of TG in children with ectopia was significantly higher than in children with aplasia — 37.12 ng/ml versus 0.82 ng/ml, p< 0.05.

CONCLUSION

CONCLUSION: Combination of two methods is the best diagnostic approach to determine the etiology of CH — ultrasound and scintigraphy studies compensates deficiencies of each other. Our study demonstrates the importance of scintigraphy in children with CH and patients with the formation of the root of the tongue and the anterior surface of the neck in order to avoid unnecessary removal of the thyroid gland. In case of confirmation of thyroid ectopia in the root of the tongue and in the absence of symptoms of obstruction or bleeding, it is recommended to refer the patient to an endocrinologist for conservative treatment.

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.

Extravasation mucocele arising from a lingual thyroglossal duct remnant

Although a thyroglossal duct cyst is a congenital anomaly, it can also appear in adults. Despite the presence of embryological remnants, it is still unclear why the cyst should suddenly develop later in life. We report a case of a 46-year-old male with an extravasation mucocele arising from a long-standing lingual thyroglossal duct remnant. MRI demonstrated a lingual cystic lesion near the hyoid bone associated with a suprahyoid tract-like structure masquerading as a thyroglossal duct cyst. However, histopathological examination demonstrated a mucocele secondary to a rupture of a thyroglossal duct remnant with numerous intramural heterotopic salivary glands. We propose a new mechanism of an acquired cystic formation of this congenital disease that excessive production of mucus from heterotopic salivary glands and a physical trauma such as swallowing may lead to extravasation of mucus from the thyroglossal duct.

Lingual Thyroidectomy

Objectives:

We report the clinical findings, surgical management, and outcomes for lingual thyroidectomy.

Methods:

We performed a retrospective case review of lingual thyroidectomy performed at 3 tertiary-care academic referral centers between 1994 and 2012.

Results:

Nine patients underwent lingual thyroidectomy for symptoms including globus sensation (6 patients), dysphagia (5 patients), and airway obstruction (5 patients). Before surgery, 3 patients had attempted medical suppressive therapy. Lingual thyroidectomy was performed by transoral laser microsurgery in 4 patients, transoral robotic surgery in 3 patients, transoral surgery without microscopic assistance in 1 patient, and an open approach with a modified Sistrunk procedure in 1 patient. Total thyroidectomy was attained in 7 patients, and subtotal resection in 2. The follow-up averaged 8 months, and all patients reported significant improvement in their symptoms. One patient had a recurrence. Complications included postoperative bleeding and epiglottic perforation in 1 patient and airway obstruction secondary to angioedema in another patient. There was no significant difference in operative times between transoral laser microsurgery (91 ± 16 minutes) and transoral robotic surgery (109 ± 35 minutes). Transoral surgery without microscopic assistance and open resection had longer operative times (206 and 246 minutes, respectively).

Conclusions:

Surgical resection of lingual thyroid glands achieves significant improvement in patient symptoms, with low rates of recurrence. We favor a total lingual thyroidectomy approach with use of either a microscope or a robotic endoscope for optical assistance.

A novel technique for the resection of the symptomatic lingual thyroid: transoral robotic surgery

BACKGROUND

Treatment of the symptomatic lingual thyroid is typically accomplished through surgical resection using a transcervical approach, which carries a high risk of treatment-related morbidity and leaves a visible scar on the neck. In order to reduce morbidity and eliminate visible scarring, this study utilized transoral robotic surgery (TORS) in performing lingual thyroidectomy.

METHODS

Between October 2009 and October 2010, three patients with symptomatic lingual thyroid were enrolled in this prospective study. Primary symptoms included dysphagia (two patients) and hemorrhage (one patient). A da Vinci robotic system (Intuitive Surgical, Inc., Sunnyvale, CA) was used to perform TORS in all patients. A face-up 30° endoscope was inserted through the oral cavity, and two instruments were positioned on either side of the endoscope. We evaluated the robotic set-up time, operating time, volume of blood loss, surgery-related complications, postoperative symptomatic improvement, and cosmetic results.

RESULTS

The transoral robotic lingual thyroidectomy was successfully performed in all patients. The mean operating time was 43 minutes (range 35-50 minutes), and an average of 11 minutes (range 10-15 minutes) was required to set up the robotic system. All patients were satisfied with their cosmetic results and the improvement of their symptoms after the operation. There were no perioperative complications or significant bleeding. The average volume of blood loss during the operation was 25 mL.

CONCLUSIONS

The use of TORS for lingual thyroidectomy was both technically feasible and safe, suggesting that it may be considered a viable alternative to other invasive surgical approaches in patients with symptomatic lingual thyroid.

Dysphonia associated with lingual thyroid gland and hypothyroidism: improvement after lingual thyroidectomy

We present a unique and medically complex case of improved voice after lingual thyroidectomy. A 10-year-old boy with multifactorial dysphonia presented with bilateral vocal fold lesions and sulci in the context of hypothyroidism as a result of a congenital lingual thyroid gland. Despite hormone replacement, medical treatment for asthma, allergy, cough, and possible reflux, as well as voice therapy, the dysphonia persisted. Significant improvement in both subjective and objective voice measures was achieved after surgical removal of the lingual thyroid gland, which allowed for maintenance of a consistent euthyroid state. Lingual thyroidectomy is typically reserved for cases of bleeding and dysphagia. This case supports dysphonia as a possible additional indication for lingual thyroidectomy.

Increased serum thyroglobulin levels and negative imaging in thyroid cancer patients: are there sources of benign secretion? A speculative short review

After thyroidectomy and 131I ablation for differentiated thyroid cancer (DTC), serum thyroglobulin (Tg) became a sensitive marker of residual disease. It is not uncommon to find patients at follow-up with persistent serum Tg levels and no other clinical or imaging evidence for the disease. The vast majority of these patients, most probably, have occult foci of disease, often in minute cervical lymph nodes. A review of the literature including papers published on PubMed/Medline until June 2010 was made. In this study we speculated that a minority of patients who had undergone surgery for differentiated thyroid cancer might have benign sources of Tg secretion at follow-up. These sources may be foci of radio-resistant ectopic thyroid tissue or a thyroid stimulating hormone-stimulated thymus.

Resistance to thyroid hormone in a patient with thyroid dysgenesis

We report a patient with the unusual coincidence of two rare congenital disorders, lingual ectopy of the thyroid gland and resistance to thyroid hormone (RTH), resulting in impaired thyroid hormone production and action, respectively. The proposita had a positive thyrotropin (TSH) newborn screening test (350 mU/L, confirmed) with normal thyroxine (T4) and no clinical signs of hypothyroidism. A scintiscan revealed lingual but no orthotopic thyroid tissue. Levothyroxine (LT4) replacement failed to reduce TSH and was discontinued after four months owing to significantly elevated free T4. Her physical and mental development was unremarkable, and she was considered to be clinically euthyroid throughout childhood, even though she received either no T4 or a dose insufficient to lessen hyperthyrotropinemia. At the age of 15 years, T4 was gradually increased to a supraphysiological dose of 300 microg/d, resulting in the normalization of the serum TSH level, and subjective improvements in her ability to concentrate. The proposita's mother was clinically euthyroid, had a palpable diffuse goiter, and thyroid function tests consistent with RTH. This diagnosis was confirmed by detection of a heterozygous mutation (R320H) in the thyroid hormone receptor-beta (TR-beta) gene found in both the proposita and her mother. Under the high-dose T4 regimen, the patient's TSH and free T4 values resembled those of untreated patients with TRbeta R320H mutation, suggesting that a compensated state could be achieved, at least at the pituitary level. In the proposita, treatment of hyperthyrotropinemia is clearly mandatory because of potential complications inflicted by TSH-stimulated growth of the lingual tissue. To our knowledge, this represents the first report of congenital hypothyroidism secondary to thyroid dysgenesis complicated by coincidental RTH.

Hypothyroidism caused by a nonvisible lingual thyroid

BACKGROUND

Lingual thyroid is a developmental anomaly caused by failure of migration of the thyroid gland to its normal position in the neck. This anomaly is usually manifested in childhood as hypothyroidism or local symptoms.

METHODS

We present a case of a 32-year-old patient in whom lingual thyroid was diagnosed after complaints of a chronic cough. Thyroid-stimulating hormone levels were significantly elevated. Sonograms of the neck revealed atrophy of both thyroid lobes, with nonhomogeneous consistency and no lymphadenopathy. Technetium-99m scan revealed uptake at the tongue base, with no uptake at the neck or other locations.

RESULTS

L-thyroxine treatment was begun, with progressive decrement in thyroid-stimulating hormone levels and cessation of the cough.

CONCLUSION

This case is unique in both the advanced age of the patient and the unusual clinical presentation.

Laryngeal mask airway guided fibreoptic tracheal intubation in a child with a lingual thyroglossal duct cyst

The establishment of a tracheal airway with direct laryngoscopy can either be difficult or impossible in children with airway pathology. Multiple direct laryngoscopic attempts cause oedema and/or bleeding with subsequent difficult ventilation. The techniques utilizing the laryngeal mask airway (LMATM) and the fibreoptic bronchoscope have been reported. The case of a child with lingual thyroglossal duct cyst in which the LMA was useful to secure the airway and as a conduit for fibreoptic tracheal intubation is reported.

Thyroid dysfunction in a patient with aglossia

We report a Thai girl who had aglossia, micrognathia, microsomia, collapse of mandibular arch, persistence of buccopharyngeal membrane, microcephaly, and mild developmental delay. Thyroid function tests indicated that she had subclinical hypothyroidism. Thyroid scan revealed normal uptake of the whole thyroid gland. Tongue morphogenesis is integrally linked to the normal development of thyroid gland, and abnormal tongue morphogenesis could potentially result in a functional thyroid disorder. We propose that micrognathia, microsomia, congenital absence of mandibular incisors, and collapse of the mandibular arch are the result of abnormal tongue development.

Lingual thyroid carcinoma: a case report and review of the literature

Ectopic thyroid tissue may reside anywhere along its embryologic path of descent. Most ectopias manifest as simple thyroglossal duct cysts in conjunction with a normally developed thyroid gland in its usual thyroid cervical bed. Lingual thyroid is a rare developmental abnormality characterized by the failure of the thyroid gland, or remnants, to descend from its embryologic site of origin at the foramen cecum to its usual pretracheal position. Carcinoma arising in a lingual thyroid is even more unusual with fewer than 30 cases reported in the literature. We report the second case of lingual papillary thyroid carcinoma and review the clinical features, natural history, diagnosis, and treatment of lingual thyroid carcinoma.

Lingual thyroid: iodine 131: a viable treatment modality revisited

PURPOSE

Lingual thyroid has a reported incidence between 1:10 and 1:100,000. When symptomatic, patients may present with dysphagia, choking, and/or dyspnea. Current surgical treatment options range from tumor extirpation or transposition to excision and reimplantation. Tracheotomies are often performed postoperatively for reliable airway control. Iodine 131 (131I) has not been a popular modality of treatment for lingual thyroid because of theoretical fears of increased airway obstruction from thyroiditis. We believe that these fears were not substantiated, and that symptomatic patients needed a reliable, nonsurgical treatment option. Therefore, our goal was to further investigate the use of 131I for the treatment of symptomatic lingual thyroid.

PATIENTS AND METHODS

A 6-year retrospective chart review was performed. From 1994 to 2000, 2 patients with symptomatic lingual thyroid presented to the Arkansas Cancer Research Center Head and Neck Oncology clinic, University of Arkansas for Medical Sciences, Little Rock, AR. Patients underwent pretreatment computed tomography, and iodine 123 scans. They then received 1 oral dose of 131I. Doses ranged from 30 to 85 mCi. Patients were then followed daily for signs of airway compromise.

RESULTS

Complete resolution of symptoms was seen 2 months after treatment. Patients did not complain of any increased airway compromise during treatment initiation. Patients remain symptom-free and are maintained on thyroid hormone replacement.

CONCLUSIONS

Iodine 131 ablation of lingual thyroid is a safe and effective treatment in symptomatic patients and should be included in the algorithm when formulating a treatment plan.

Cribriform adenocarcinoma of the tongue: a hitherto unrecognized type of adenocarcinoma characteristically occurring in the tongue

AIMS

We report a review of our institutional and consultation files in order to select cases of hitherto unrecognized type of adenocarcinoma occurring in the tongue.

MATERIALS AND RESULTS

Eight cases of a characteristic adenocarcinoma of the tongue resembled solid and follicular variants of the papillary carcinoma of the thyroid. All the tumours were unencapsulated and were divided by fibrous septa into lobules. Major parts of the lesions were composed of areas with solid and microcystic growth patterns. The most striking cytological feature was that the tumour nuclei were pale-staining with a 'ground glass' quality, and they often appeared to overlap. Immunohistochemically, the tumours expressed cytokeratin and S100 protein and, focally, actin; thyroglobulin was negative. Ultrastructurally the cells had clefted nuclei, and the cytoplasm contained a few mitochondria, lysosomes and Golgi apparatus. Many tumour cells had combined features of both myoepithelial and secretory differentiation-well formed microvilli on their apical borders and bundles of microfilaments. At first presentation, all eight patients had metastases in the regional neck lymph nodes, but all are alive 2-6 years after the initial excision and irradiation.

CONCLUSION

We describe a distinctive type of adenocarcinoma of the tongue, for which we propose the name cribriform adenocarcinoma of the tongue (CAT). CAT usually presents with metastases in the neck lymph nodes at the time of presentation. We hypothesize that the tumour might arise from the thyroglossal duct anlage.

Lingual thyroid gland: Clinical evaluation and comprehensive management

Although lingual thyroid gland is the most common benign mass found at the junction of the anterior two-thirds and the posterior one-third of the tongue, it is still a rare clinical entity. This developmental anomaly is the result of an arrested descent of the gland anlage early in the course of embryogenesis. Patients may have symptoms of dysphagia due to obstruction or even hemorrhage. These symptoms can occur at any time from infancy through adulthood. The clinical findings, laboratory tests, and radiographic imaging studies employed in confirming the diagnosis and in planning appropriate treatment have been evaluated. The primary therapeutic goal is to restore thyroid function. We describe a case of lingual thyroid gland and summarize the current management principles for this condition.

Intralaryngotracheal thyroid--ectopic thyroid or invasive carcinoma?

Intralaryngotracheal thyroid is a rare clinical condition with only about 125 cases described so far in the literature. We present an unusual case of intralaryngotracheal thyroid which had many clinical features of malignancy and yet appeared benign on histology. As in this case, well-differentiated thyroid cancer can present with locally aggressive clinical features and can pose a dilemma in management if treatment decisions are guided solely by histological features.

Clonal analysis helps to differentiate aberrant thyroid tissue from thyroid carcinoma

A rare case of multiple aberrant of thyroid tissues in the tongue and lymph nodes of the bilateral neck was studied by immunohistochemistry and molecular clonal analysis to determine whether these tissues represent aberrant ectopic thyroid or metastases of a thyroid carcinoma. The thyroid tissues in the tongue and lymph nodes were all of polyclonal origins, consistent with ectopic thyroid in the tongue and bilateral cervical lymph nodes, rather than malignant thyroid tissues. This case shows that molecular clonal analysis can be used to distinguish aberrant thyroid from metastases of thyroid carcinoma.

Follicular carcinoma in lingual thyroid presenting as a latero-cervical mass. Case report and review of the literature

A follicular carcinoma arising in a lingual thyroid and presenting as a submandibular mass is reported. The tumor showed a mixture of solid sheets of follicular cells and well-formed follicles displaying variable levels of cytological atypia. True vascular invasion was confirmed. To the best of our knowledge, this is the first example of carcinoma arising in lingual thyroid that presented as a latero-cervical mass.

Thyroid gland ectopias

Failures of descent of the medial anlage of the thyroid and incomplete obliteration of its vertical tract lead to midline or near-midline ectopias such as lingual thyroid and thyroglossal cysts. Each poses special diagnostic and therapeutic considerations. "Ectopias" of the thyroid gland lateral to the carotid artery and jugular vein, however, cannot be readily explained by current embryological information. In these instances, and especially for intranodal thyroid tissue, a metastasis from an occult thyroid primary is the mandatory first consideration.

Lingual thyroglossal duct cyst: a unique surgical approach

Thyroglossal duct cyst (TGDC) is one of the more common causes of a pediatric neck mass. Lingual TGDC, which is located at the base of the tongue, is an unusual variant. Because of the oral pharyngeal location, lingual TGDC may cause dysphagia and respiratory distress. Previous investigators have advocated the use of a formal Sistrunk procedure for lingual TGDC. Herein the authors describe three children with a lingual TGDC in whom marsupialization of the cyst was performed, without excision. The follow-up period ranges from 2 to 5 years, and there has been no recurrence. Because of the low morbidity and high success rate associated with this approach, the authors recommend it for the treatment of lingual TGDC.

Developmental lesions of the head and neck: terminology and biologic behavior

As much confusion has been generated in the literature by the inaccurate or improper use of terms describing developmental lesions such as hamartoma, choristoma, and teratoma, a number of different benign and malignant developmental lesions are described and distinguished in the hope that these lesions can be more reliably identified and consequently also more adequately managed.

Lingual thyroid: a new surgical approach--a case report

Ectopic lingual thyroid is a rare developmental anomaly, presenting in the adult with obstructive symptoms during respiration, deglutition and speech. The main therapeutic issue after exact diagnosis is the restoration of thyroid function, and surgical intervention, when necessary, has to deal with problems related to the site and function of the ectopic gland. A case of a 25-year-old female with dyspnoea and dysphagia due to a 3 x 4 cm ectopic lingual thyroid, excised by an original peroral approach via a mandibular midline osteotomy, is reported. Our surgical technique is described and the diagnostic and therapeutic problems are reviewed.

Thoracic intrathymic thyroid

OBJECTIVE

The authors introduce thoracic intrathymic thyroid as a clinical entity.

SUMMARY BACKGROUND DATA

Although accessory aberrant thyroid has not been found in other tissues in the mediastinum, a thoracic intrathymic location has not been described previously. It is believed that mediastinal thyroid tissue represents accessory ectopic tissue from the median thyroid anlage. Moreover, the close association of the thymus and thyroid supports the theory that mediastinal ectopic thyroid tissue develops from abnormal descent of these structures during embryogenesis.

METHODS

Benign thoracic intrathymic thyroid lesions are described in patients with mediastinal masses.

CONCLUSION

Thoracic intrathymic thyroid is a distinct entity. Its occurrence is supported both clinically and embryologically.

Lingual thyroid presenting after previous thyroglossal cyst excision

Lingual thyroid is a rare lesion caused by maldescent of the thyroid gland. It is an important cause of a mass on the posterior third of the tongue, and may coexist with other developmental abnormalities such as thyroglossal cyst. The diagnosis is made by radioisotope scan. Treatment is indicated in the presence of symptoms and consists initially of thyroxine. Severe or unresponsive cases require complete excision through a lateral pharyngotomy. Hypothyroidism is common postoperatively, but may be avoided in some cases by transplantation of excised tissue. We present a case report and review of the literature.

Lingual thyroid

Lingual thyroid is a rare cause of dysphagia and airway obstruction. A case is presented, with a discussion of the diagnosis and management.

Follicular carcinoma with clear cell change arising in lingual thyroid

A case of follicular carcinoma arising in the lingual thyroid of a 23-year-old woman is added to the 22 previous reports. The embryology and the clinical and pathologic differential diagnoses are discussed. Histologic criteria useful in diagnosing follicular malignancy in this area include local and vascular invasiveness, hypercellularity, mitotic activity, and necrosis. The use of the immunohistochemical marker thyroglobulin and electron microscopy are described for the first time and confirm a thyroid follicular cell origin.

Investigating a lingual thyroid

During a 15-year-period, in a thyroid investigation centre in Sri Lanka comprising 16,593 cases, 8 lingual thyroids were seen. All patients were female. Radioisotope studies and scintiscanning performed during the investigations of these cases are presented. All subjects were euthyroid at presentation and the clinical courses of 5 cases during follow-up are discussed.

Choristomas of the oral cavity: a review

The choristoma is a tumorlike mass of normal cells in an abnormal location. Intraoral choristomas have been reported under a wide variety of names. This comprehensive review of the English-language literature on oral choristomas offers a classification of these lesions, analyzes their clinical and histologic features, and discusses possible pathogeneses and treatment.

Ectopic thyroid tissue in the submandibular region

This report describes an unusual location of ectopic thyroid gland tissue. A growth in the left submandibular area was surgically excised, and the microscopic examination of the specimen revealed thyroid tissue with colloid goiter. Because this entity cannot be clinically distinguished from a salivary gland tumor, ectopic thyroid tissue should be considered in the differential diagnosis of swellings involving the submandibular area.

Clinical orodental abnormalities in Mexican children

A total of 32,022 Mexican children (16,473 boys, 15,549 girls) were examined for several congenital oral and paraoral anomalies. The findings for commissural lip pits (boys 53.1, girls 52.4 per 1000) are less than those reported for adults. This may indicate that pits become accentuated with age. Fordyce granules were seen with a prevalence of 1.2 per 1000. This is in contrast to the reported 85.6% prevalence for the adult population, also possibly reflecting increased manifestation with increased age. Our data for exogenous tooth pigmentation show increased prevalence with age (group I [5 to 10 1/2 years], 9.8%, versus group II [10 1/2 to 14 1/2 years], 12.9%), possibly indicating decrease in attention to oral hygiene. The prevalence of talon cusp was found to be 0.6 per 1000, and for ankyloglossia 8.3 per 1000. Prevalence values for bifid tongue are reported for the first time, indicating one affected per 187 children examined. The prevalence of fissured tongue (15.7%) shows a statistically significant difference between boys (16.8%) and girls (14.5%). The prevalence of geographic tongue (1.9%) shows a marked difference between group I (2.2%) and group II (1.2%).

Lingual thyroid in a young infant presenting as airway obstruction: report of a case

A case of lingual thyroid causing airway obstruction in a 3-month-old infant is reported. Endoscopic examination for stridor disclosed an obstructing 4 X 3 cm base of tongue lesion. Nuclear isotope scanning confirmed this to be the only thyroid tissue present in this patient. A transoral excision using the CO2 laser was performed without complication. Only one other case of airway obstruction in the young infant secondary to lingual thyroid has been reported, that being the original case description in 1869. A review of the embryology and discussion of the suggested therapies is presented. The rationale for use of the CO2 laser for this lesion is discussed.

Lingual thyroid

Lingual thyroid is a rare occurrence in oral surgical practice. A case is reported, accompanied by a current view of the previous literature. A brief resumé of methods of treatment is given and the importance of investigation before excision biopsy is emphasised.

The thyroglossal cyst

The thyroglossal cyst is the most common nonodontogenic cyst in the neck. This cyst may also occur in the lingual or submental areas, though more rarely. Malignant changes have been described. Clinically, no differentiation between a benign cyst and a malignancy can be made. The literature is reviewed regarding the embryology, epidemiology, etiology, symptomatology, radiology, histology, and treatment of this cyst and its malignant counterpart.

Ectopic thyroid gland. A clinical study of 30 children and review

Of 108 children being treated at our Institute for primary (nongoitrous) hypothyroidism, tests with radioactive iodine 131I uptake showed that 26 of them (24%) had an ectopic thyroid gland. Four euthyroid children also had anterior swellings of the neck which, in each case, proved to be an ectopic thyroid gland. Of the 30 children studied, 20 were girls and 10 were boys. Nine patients were diagnosed within the first year of life. Growth retardation, manifest in 20 patients, was the most common clinical finding at the time of diagnosis. Delayed bone age was a feature in all of them. Growth, after diagnosis was within normal limits in 83% of the infants who were treated within the first two years of life; only 50% of the children diagnosed later grew within normal limits. Similarly, mental function was best preserved in those patients in whom treatment was initiated within the first two years of life.

Thyroglossal-tract cyst

Thyroglossal-tract cyst should be included in the differential diagnosis of any mass found in the anterior midline of the neck. A discussion and review of forty-two cases diagnosed between 1970 and 1976 at Wilford Hall USAF Medical Center are presented.

Lingual sebaceous glands: report of case

A 28-year-old dentist noticed a 9X5-mm yellow submucosal plaque in the midlateral dorsum of his tongue. After a period of observation an excisional biopsy was performed. The histopathologic examination of the specimen revealed normal sebaceous glands opening onto the tongue surface. This occurrence of ectopic sebaceous glands in the tongue is notably rare in contrast with their frequent occurrence in the lips and buccal mucosa.