Case of thyroid hemiagenesis and ectopic lingual thyroid presenting as goitre

Thyroid Hemiagenesis Accompanying an Ectopic Lingual Thyroid

Lingual thyroid is an uncommon condition and cases accompanying thyroid hemiagenesis are rarely documented. Patients with thyroid hemiagenesis are usually asymptomatic and generally diagnosed incidentally. Herein, we reported the case of thyroid hemiagenesis accompanying an ectopic lingual thyroid with euthyroidism and presented with regional symptoms.

Thyroid Hemiagenesis: Narrative Review and Clinical Implications

Thyroid Hemiagenesis (THA) is an uncommon, congenital anomaly defined by the absence of one thyroid lobe with or without the isthmus. Reports suggest it may be found more often in regions endemic for hypothyroidism. Genetic abnormalities are thought to have a role based on findings in monozygotic twins. Most cases are sporadic, however familiar clusters have also been documented. It is found more frequently in females. A majority of patients report no symptoms and THA is found incidentally during investigations or intraoperatively. THA is usually associated with normal thyroid function, but it can present with thyroid hypofunction.

Since a majority of patients are asymptomatic, there are no specific recommendations for management. Ultrasound imaging and thyroid scintigraphy using technetium or iodine are useful in diagnosis. Its clinical importance occurs when the remnant thyroid lobe requires excision leading to the lifelong requirement for thyroxine supplementation.

Published English literature (Medline, PubMed, and Embase databases) was searched. Medical subject headings (MeSH) terms used were “thyroid hemiagenesis,” “one thyroid lobe,” and “thyroid aplasia”. Case reports, case series, and original articles were selected to provide a framework for this review.

Articles reviewed were published in the past 20 years. The association of THA with thyroid cancer was explored. In this group, the F:M ratio was 3.25:1. Left THA constituted 53% of cases, right THA in 29.4%, and isthmus absence in 17.6% of cases. Also, the authors investigated the link between THA and hyperparathyroidism, both left and right THA are seen in an equal number of cases in the hyperparathyroidism subgroup. In patients with THA and Grave’s disease, left THA was seen in a majority of cases (86.7%), while an equal number of left and right THA was observed in patients with Hashimoto’s thyroiditis. In addition, congenital abnormalities associated with THA were observed, the left THA was seen in 60% and right THA in 40% of cases of this subgroup.

The summative review provided a detailed insight into the epidemiology, aetiopathogenesis, genetics, symptomatology, diagnosis, and treatment for THA by combining findings and results from almost a hundred research papers from around the world. THA remains a poorly understood, often incidentally detected, abnormality in euthyroid patients undergoing investigations and treatment for other thyroid disorders.

Thyroid Carcinoma on the Side of the Absent Lobe in a Patient with Thyroid Hemiagenesis

Background

Thyroid carcinoma complicated by hemiagenesis is very rare, and previous reports have not described this cancer on the side of the absent lobe.

Methods and Results

We report the case of a 64-year-old woman in whom left thyroid hemiagenesis was discovered incidentally during investigations of abnormal sensation during swallowing. A tumorous 1.4 cm lesion was also found on the side of the absent lobe, left of the isthmus. Fine-needle aspiration biopsy revealed class V papillary carcinoma, but no lymph node metastases. Total thyroidectomy was performed for stage cT1bN0M0 carcinoma. Histopathology revealed normal thyroid tissues in the right lobe and isthmus, while the left lobe was absent. The mostly papillary carcinoma was adjacent to the truncated thyroid tissue, with a portion histologically consistent with poorly differentiated carcinoma.

Conclusions

All previously reported cases of thyroid cancer complicated by hemiagenesis have represented carcinoma occurring within the present lobe. This case is extremely rare.

Thyroid Hemiagenesis: Incidence, Clinical Significance, and Genetic Background

CONTEXT

Thyroid hemiagenesis (THA) constitutes a rare, congenital disorder that is characterized by an absence of one thyroid lobe. Because the pathogenesis and clinical significance of this malformation remain undefined, specific clinical recommendations are lacking, especially for asymptomatic cases.

EVIDENCE ACQUISITION

The PubMed database was searched (years 1970 to 2017), and the following terms were used to retrieve the results: "thyroid hemiagenesis," "thyroid hemiaplasia," "one thyroid lobe agenesis," and "one thyroid lobe aplasia." Subsequently, reference sections of the retrieved articles were searched.

EVIDENCE SYNTHESIS

There is a noticeable susceptibility of subjects with THA to develop additional thyroid and nonthyroidal pathologies. In pathogenesis of concomitant thyroid pathologies, a chronic elevation in thyroid-stimulating hormone values may play an important role. Thus far, genetic studies failed to find a common genetic background of the anomaly, and the potential underlying cause was identified in a minority of the cases.

CONCLUSIONS

Patients with THA are prone to develop additional thyroid pathologies and theoretically might benefit from l-thyroxine treatment to lower the thyrotropin levels to those observed in the normal population. However, further research should be done to ascertain whether such intervention early in life would prevent development of associated thyroid conditions. At least, increased vigilance should be maintained to reveal all of the concomitant disorders as soon as possible during follow-up examinations. Application of high-throughput technologies enabling a genome-wide search for novel factors involved in thyroid embryogenesis might be the next step to expand the knowledge on THA pathogenesis.

Does TSH Trigger the Anti-thyroid Autoimmune Processes? Observation on a Large Cohort of Naive Patients with Thyroid Hemiagenesis

Thyroid hemiagenesis (THA) is a rare abnormality characterized by the absence of one thyroid lobe. Elevated thyroid stimulating hormone (TSH) level and higher incidence of thyroid diseases were reported in THA. The aim of the study is to evaluate the thyroid autoimmunity incidence in patients with THA and influence of higher than average TSH level on thyroid volume (TV) and its change with age. The study included a group of naive patients with THA and a control group of subjects with bilobate thyroid. All patients underwent clinical examination, thyroid ultrasound, scintiscan and laboratory tests. In the studied and control group the presence of thyroid autoantibodies (TAb) was evaluated. The THA group consisted of 65 patients. In THA group 53.85 % of patients were positive for TAb. Patients with positive TAb were older (46.0 ± 18.3 years) than those with negative (35.0 ± 19.8 years); p = 0.02. The incidence of TAb was lower in controls (13.85 %, p < 0.0001). In the study group, positive correlation between the age and TV (r = 0.46, p = 0.0001), and negative correlations between the age and TSH level (r = −0.31, p = 0.01), and TSH concentration and TV (r = −0.35, p = 0.004) were found. In a subgroup of 30 patients with THA negative for TAb, even stronger correlations were observed. The median single lobe volume and median TSH level were higher in patients with THA when compared to controls (13.60 vs 8.20 ml, p < 0.0001; 3.23 vs 1.48 µU/ml, p < 0.0001, respectively). Patients with THA constitute an in vivo model of long-term thyroid TSH overstimulation. Further studies are needed to reveal, whether TSH overstimulation may be the trigger for thyroid autoimmunity.

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.

A case of hemiagenesis of thyroid with double ectopic thyroid tissue

Developmental abnormalities of the thyroid gland are very rare. The most common abnormalities include ectopic thyroid tissues that are commonly seen in lingual or sublingual location, agenesis, and hemiagenesis of the thyroid gland. These developmental defects may or may not be associated with thyroid dysfunction. Our case is an 18-year-old male who presented with swelling in the neck of 4-year duration. Clinical examination revealed an oval-shape swelling in the left side of the thyroid gland. The ultrasound and the nuclear scan report revealed the presence of thyroid hemiagenesis of the right lobe with isthmus along with double ectopic thyroid tissue at suprahyoid and infrahyoid region. His thyroid function test showed elevated thyroid-stimulating hormone (TSH) and normal free T4. We report a very rare case of thyroid hemiagenesis with double ectopic thyroid tissue; and to the best of our knowledge, this is the first report in the world literature.

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.

Left thyroid hemiagenesis in a patient with primary hyperparathyroidism

The case of a patient with primary hyperparathyroidism with the incidental finding of left thyroid hemiagenesis with isthmus involvement is presented. Thyroid hemiagenesis is a rare congenital abnormality. There have been approximately 310 cases reported in the literature to date. It has been reported as an incidental finding with a wide range of associated pathological conditions. It is important to consider this in patients being prepared for thyroid lobectomy due to the inevitability of postoperative hypothyroidsm. Due to the female predominance of thyroid disease, hemiagenesis was first thought to be more common in women. Left lobe cases accounts for the majority of instances and isthmus is absent in half the cases. Ultrasonography is the diagnostic tool of choice.