Hemiaplasia of the thyroid associated with Graves' disease: report of three cases and a review of the literature

Unilateral Graves' Disease in a Bilobar Thyroid Gland: A Very Unusual Cause of Hyperthyroidism

Graves' disease (GD) is an autoimmune condition that affects both thyroid gland lobes. Patients with GD with unilateral thyroid scan uptake are rare. These patients present with classic Graves' symptoms, occasionally with Graves' ophthalmopathy characteristics and increased thyroid hormones, and scintigraphic assessment reveals radiotracer uptake in only 1 lobe of the thyroid gland. In this case, a 48-year-old female presented with symptoms and signs indicative of thyrotoxicosis. Laboratory results revealed that TSH was undetectable, whereas free thyroxine and free triiodothyronine were in the high-normal range. Positive results were observed for both thyroid-stimulating Ig and TSH receptor antibodies. Ultrasonography of the thyroid gland revealed an enlarged left lobe with heterogeneous echotexture and a hyperemic gland without any focal lesions, distinct nodules, or cysts. Thyroid scintigraphy revealed enlarged and increased radioisotope uptake in the left lobe and decreased uptake in the right lobe, with no hot or cold nodules. The most likely diagnosis was unilateral GD. The patient was administered carbimazole and within 8 weeks had improved clinically and biochemically.

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.

A case report of 131I therapy for Graves' disease patient with hemiagenesis

RATIONALE

Thyroid hemiagenesis is a rare congenital dysplasia, whereas a variety of pathological changes may occur in residual thyroid lobe. The most frequently described pathology in residual thyroid lobe is Graves' hyperthyroidism. Although I therapy has been generally recommended as the preferred treatment for Graves' disease (GD), subjects relating to hemiagenesis are very limited, especially in China.

PATIENT CONCERNS

A 43-year-old female patient presented to our hospital on November 2014, with a 1-year history of palpitation, fatigue, and hand tremor. Her situation was getting worse within 2 months.

DIAGNOSIS

The thyroid function tests were suggestive of thyrotoxicosis. The technetium thyroid scintigraphy only showed an enlarged right lobe with increased tracer uptake. Then, the agenesis of left lobe and isthmus was confirmed by ultrasound and magnetic resonance imaging (MRI). Thus, a diagnosis of GD with hemiageneis of the left lobe and isthmus of thyroid was made.

INTERVENTIONS

Thiamazole was discontinued because of drug-induced hepatic injury. According to our procedures, the patient was treated by I.

OUTCOMES

Hypothyroidism was observed 3 months after I therapy. After replacement therapy with L-thyroxine (LT4), the state of euthyroid maintained.

LESSONS

Once hypothyroidism occurs, regular application of LT4 and review of thyroid function is very important. Thus, patients' compliance needs to be strengthened. Besides, we could not convince the family members of our patient to undergo ultrasonographic examination. The genetic factor of the agenesis could not be proved in this case.

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.

THYROID HEMIAGENESIS ASSOCIATED WITH GRAVES' DISEASE: A CASE REPORT AND REVIEW OF THE LITERATURE

Introduction

Thyroid hemiagenesis (TH) is a congenital developmental disorder. Most cases are euthyroid although hyperthyroidism, hypothyroidism, and malignancy may develop. We present a case of hemiagenesis with Graves' disease (GD) and review the literature about the association.

Case report

A 45-year-old female patient was admitted to the endocrinology department due to nausea and diarrhea. Her past medical history revealed hyperthyroidism diagnosed a year ago. On thyroid examination, right thyroid lobe was palpable, but left lobe and isthmus were not. Physical examination involving other organ systems was unremarkable except for fine tremor of the hands. Thyroid function tests revealed a high level of free T4 and T3 with a low serum TSH. Thyroid antibodies were all positive. Left lobe and isthmus were invisible on thyroid ultrasonography (US) and the right thyroid lobe measuring 44x18x12 mm was diffusely heterogeneous in echo texture. Thyroid scan using Technetium-99m showed increased homogeneous tracer uptake in the right lobe. The patient was diagnosed with TH and GD.

Discussion

In case of unilateral increased uptake on scintiscan, GD with hemiagenesis must be kept in mind in the differential diagnosis of autonomous solitary adenoma, postinflammatory atrophy of thyroid in Hashimoto's disease, focal or unilateral subacute thyroiditis, and primary or metastatic carcinoma. It is prudent to do thyroid ultrasound along with scintigram. US is a valuable tool for the quick diagnosis of TH and differential diagnosis from other causes.

Thyroid hemiagenesis associated with medullary or papillary carcinoma: report of cases

BACKGROUND

Thyroid hemiagenesis is a rare congenital anomaly in which 1 thyroid lobe fails to develop. Co-occurrence of hemiagenesis and thyroid carcinoma is extremely rare. Here, we report 2 cases of thyroid hemiagenesis with carcinoma.

METHODS

The first patient was referred with a left thyroid mass and absent right lobe. The frozen section examination revealed medullary thyroid carcinoma (MTC); therefore, a left thyroid lobectomy plus neck dissection was performed. Another patient was referred with a right thyroid mass and absent left lobe. Fine-needle aspiration biopsy was suspicious for papillary carcinoma. The patient underwent right thyroid lobectomy plus neck dissection.

RESULTS

The operative findings confirmed hemiagenesis of the right lobe and MTC in the left lobe for the first case, and hemiagenesis of the left lobe and papillary carcinoma in the right lobe for the second case.

CONCLUSION

Our case represents the first reported case of association between thyroid hemiagenesis and MTC.

Unusual thyroid constellation in Down syndrome: congenital hypothyroidism, Graves' disease, and hemiagenesis in the same child

We report a girl with Down syndrome who was diagnosed with congenital hypothyroidism in the newborn period due to left thyroid hemiagenesis. Unexpectedly, her hypothyroidism resolved at the age of 3 years. After being off thyroid hormone replacement for 7 years and having normal thyroid function, she developed Graves' disease. Although Graves' disease in association with thyroid hemiagenesis has previously been reported, this represents the youngest patient in whom this scenario has been described. Issues pertaining to thyroid hemiagenesis, autoimmune hyperthyroidism, and thyroid disease in children with Down's syndrome are discussed.

A singular case of Graves' disease in congenital thyroid hemiagenesis

We report the observation of an unusual case of Graves' disease associated with thyroid hemiagenesis. A 41-year-old woman who presented with symptoms and clinical signs of hyperthyroidism was discovered to have thyroid hemiagenesia of the left lobe. Thyroid ultrasound scan showed enlargement of the right lobe with a single nodule, and absence of the left lobe; isotope scan showed homogeneous uptake in the single lobe and nodule. Ophthalmopathy, which was absent at presentation, developed after two years; after a further 2 years the patient developed decompensated hypothyroidism requiring thyroxine replacement. This is the first case of Graves' disease in thyroid hemiagenesis evolved to hypothyroidism, and a rare case of thyroid ophthalmopathy accompanying this condition.

Thyroid hemiagenesis and incidentally discovered papillary thyroid cancer: case report and review of the literature

Thyroid hemiagenesis (TH) is a rare congenital abnormality in which one thyroid lobe fails to develop. Its prevalence is uncertain, because the absence of one thyroid lobe does not usually cause clinical symptoms. The detection of TH is usually incidental when the evaluation of other thyroid disorders is requested. It is more frequently found in female than in male patients (3:1 ratio) and in the left lobe compared to the right lobe. We report the case of a 54-yr-old man, presenting with a large multinodular right-sided goiter, with mediastinal extension and dysphagia. Thyroid scan and ultrasound study showed the absence of the left lobe. The patient underwent surgery for compressive symptoms, and the operation confirmed the absence of the left lobe. Histological examination demonstrated a multi-nodular goiter with papillary carcinoma. To our knowledge, this case represents the first reported case of association between TH and papillary thyroid carcinoma in a male patient, and the second in which the tumor arose in the right lobe.

Thyroid hemiagenesis with postpartum silent thyroiditis

A 28-year-old woman with thyroid hemiagenesis, who had been diagnosed as having Graves' disease, became pregnant during the course of methimazole treatment. The treatment was terminated in the second trimester. She delivered a normal infant at full term. She became thyrotoxic 3 months after the delivery, hypothyroid 6 months after the delivery, and finally euthyroid 11 months after the delivery without undergoing any treatment. This clinical course indicates that she developed silent thyroiditis after the delivery. A diagnosis of thyroid hemiagenesis was made on the basis of ultrasonography of the thyroid and 99mTc-pertechnetate thyroid scintiscan.

Thyroid hemiagenesis associated with Graves' disease and Graves' ophthalmopathy: case report

Failure of embryologic development of a lobe of the thyroid gland is a rare anomaly. Usually, this condition is diagnosed when there are some other pathologic conditions in the gland and is often found when a patient presents with a thyroid nodule, which in reality is compensatory hypertrophy of the side that is present, therefore appearing as a nodule. A variety of pathological conditions occur in the remaining thyroid tissue in association with this rare anomaly such as adenoma, carcinoma, subacute thyroiditis, colloid nodule, Graves' disease, simple goiter, and Hashimoto thyroiditis. Association of Graves' disease with ophthalmopathy and thyroid hemiagenesis is quite rare and very few cases are reported in the literature. We report a 29-year-old female presented as Graves' disease and Graves' ophthalmopathy with left lobe hemiagenesis of the thyroid gland.

Thyroid-stimulating hormone receptor and its role in Graves' disease

The thyroid-stimulating hormone (TSH, or thyrotropin) receptor (TSHR) mediates the activating action of TSH to the thyroid gland, resulting in the growth and proliferation of thyrocytes and thyroid hormone production. In Graves' disease, thyroid-stimulating autoantibodies can mimic TSH action and stimulate thyroid cells. This leads to hyperthyroidism and abnormal overproduction of thyroid hormone. TSHR-antibodies-binding epitopes on the receptor molecule are well studied. Mechanism of TSHR-autoantibodies production is more or less clear but a susceptibility gene, which is linked to their production, is still unknown. Genetic studies show no linkage between the TSHR gene and Graves' disease. Among three common polymorphisms in the TSHR gene, only the D727E germline polymorphism in the cytoplasmic tail of the receptor showed an association with the disease, and this association is weak. The absence of a strong genetic effect of the TSHR polymorphisms in such a common and complex disorder as Graves' disease may be explained by a high degree of evolutionary conservation in TSHR. This can be shown by naturally existing germline and somatic mutations in the TSHR gene that cause various types of nonautoimmune and hereditary thyroid disease.

Thyroid hemiagenesis in an endemic goiter area diagnosed by ultrasonography: report of sixteen patients

During a period of 9 years, 71,500 patients underwent thyroid investigations at our department. Sixteen patients with thyroid hemiagenesis, 13 women and 3 men, were seen during this period. Fifteen had no left lobe and only 1 had no right lobe, the isthmus was present in 5 patients. Associated thyroid diseases of the lobe that was present could be observed in 11 patients (9 diffuse or nodular goiters, 2 thyroid autoimmune diseases). One patient was hyperthyroid and 7 were hypothyroid. Hypothyroidism associated with hemiagenesis has rarely been reported in the literature. In our survey, the high percentage of hypothyroidism may be explained by coexisting iodine deficiency, which could be verified in 4 hypothyroid patients. Ultrasonography is the key investigation to diagnose thyroid hemiagenesis. Fine-needle aspiration biopsies, laboratory tests, and scintigraphies are useful to diagnose other diseases within the remaining lobe or to visualize ectopic thyroid tissue. Review of the literature, including our cases, presented a total of 256 patients with thyroid hemiagenesis. Its prevalence can be estimated between 1:1900 and 1:2675. Left to right ratio of thyroid hemiagenesis is 3.6:1 with an isthmus present in 44%. The female-to-male ratio is 3:1; however, the larger number of females is probably based on a bias due to a female predominance of the populations investigated. On the basis of an equal distribution of both sexes, the female-to-male ratio of thyroid hemiagenesis would be only 1.3:1 in our survey.

Hyperthyroidism of Graves' disease: evidence for only unilateral involvement of the thyroid gland in a 31-year-old female patient

Hyperthyroidism of Graves' disease (Morbus Basedow) is known to involve the thyroid gland in toto, unlike Graves' ophthalmopathy which clinically may either be unilateral or bilateral. We report a 31-year-old Caucasian female patient who presented with unilateral goiter and clinical and laboratory evidence for hyperthyroidism. High-resolution ultrasonography of the thyroid gland revealed a morphology indicative of an autoimmune thyroid disease strictly limited only to the right lobe. 123I-scintiscanning showed a homogenous but several fold increased uptake of the radionuclide in the right lobe of the thyroid gland, whereas the uptake in the left lobe did not differ from the uptake in normal controls. Cytology of the fine needle aspirate of the right lobe revealed a remarkable inflammatory background mainly by presence of lymphocytes, a finding which was not seen in the cytology of the left lobe. Furthermore, both serum antibodies to TSH-receptors and thyroid peroxidase were significantly increased. Consequently, hyperthyroidism of Graves' disease with the involvement of only one lobe of the thyroid gland was diagnosed.