Right thyroid lobe agenesis and left thyroid colloid benign nodule discovered incidentally in female with breast carcinoma receiving chemotherapy for multiple metastases: Case report and review of the literature.

INTRODUCTION AND IMPORTANCE: Thyroid hemiagenesis (THA) is the failure of embryologic development of a lobe of the thyroid gland and is a rare anomaly of uncertain incidence. The left lobe is more commonly absent than the right lobe. It is discovered incidentally during investigations. CASE PRESENTATION: A 48 year old Egyptian female presented at the thyroid surgery clinic at our institution to follow up after a nodule left thyroid lobe accidently discovered on positron emission tomography (PET) scan undertaken to follow up on bone metastasis of breast cancer which was surgically removed about 14 years ago. CLINICAL DISCUSSION: The patient looked clinically well with no scar in the anterior of the neck, no palpable thyroid nodules, and no lymphadenopathy. Ultrasound imaging of the neck revealed absent right thyroid lobe tissue and a nodule was noted at the upper pole of the left thyroid. Laboratory tests unremarkable, with TSH (2.14 mIU/L), and FT4 (12.4 pmol/L) within normal range. Fine needle aspiration and cytology of the thyroid nodule revealed atypia of undetermined significance. CONCLUSION: THA is rare and right THA is even rarer. It is usually asymptomatic, and diagnosis is mostly incidental while investigating symptoms due to pathology of the other thyroid lobe or any of the parathyroid glands. In much rarer circumstances, right THA might be discovered when investigating conditions not related to the thyroid or parathyroid glands years after the initial pathology as in the current case. Etiology is inconclusive but genetic factors could play a role. No treatment is required if no symptoms are present.

Computed tomography findings of thyroid hemiagenesis: differentiation from hemithyroidectomy.

OBJECTIVES: Thyroid hemiagenesis is a rare congenital anomaly characterized by the lack of development of one thyroid lobe. The purpose of this study was to evaluate computed tomography (CT) findings of thyroid hemiagenesis and to establish useful CT criteria for differentiating thyroid hemiagenesis from the hemithyroidectomy state. METHODS: The CT images of 11 patients with thyroid hemiagenesis were retrospectively reviewed and compared with those of 100 (49 left and 51 right) patients in a hemithyroidectomy state. Image analysis was performed according to the following CT parameters: (a) side of thyroid hemiagenesis, (b) edge of the medial end of the remnant thyroid gland, (c) location of the medial end of the remnant thyroid gland, expressed as the angle of the medial end and (d) any other thyroid abnormality observed during the initial examination. RESULTS: The missing lobe occurred more often in the left than in the right lobe (72.7% vs. 27.3%) as well as concomitant isthmus agenesis (100% vs. 37.5%). The sharp edge of the medial end of the remnant thyroid gland was more common in thyroid hemiagenesis (64%) than in hemithyroidectomy (26%) (P = 0.0153). In left thyroid hemiagenesis, the angle of the medial end (63%) was more frequently > + 30° than in hemithyroidectomy (0%) (P < 0.0001). Two patients presented with hypothyroidism; the remaining nine showed a normal thyroid function. The associated thyroid diseases were autoimmune thyroiditis (n = 1) and papillary thyroid carcinoma (n = 1). CONCLUSIONS: The sharp edge of the medial end of the remnant thyroid gland and an angle of > + 30° for the medial end in cases wherein the left lobe is absent are useful CT features for distinguishing thyroid hemiagenesis from hemithyroidectomy.

Papillary Carcinoma of Thyroglossal Cyst with Thyroid Hemiagenesis: Is Conservative Surgical Management Enough?

We describe a case of papillary carcinoma in a thyroglossal cyst with left hemiagenesis of the thyroid gland in a 24-year-old female patient. We opted not to perform a total thyroidectomy as the patient was at low risk for aggressive disease. In this article we review the criteria for selection of thyroidectomy in incidentally discovered papillary carcinomas after thyroglossal cyst excision and management protocol in case of coexisting thyroid hemi-agenesis. To our knowledge, this case represents the second case report of an association between left thyroid hemiagenesis and thyroglossal duct cyst papillary carcinoma.

Hypothyroidism in Thyroid Hemiagenesis: A Case Report.

Thyroid hemiagenesis is one of the rare developmental abnormalities of the thyroid. It is more common in women and more commonly found on the left side, often associated with the absence of isthmus. In most instances, thyroid hemiagenesis is presented with hyperthyroidism. This case report aimed to present a 72-year-old female who presents with thyroid hemiagenesis and associated hypothyroidism. She was initially diagnosed with hypothyroidism about 25 years ago. There was no family history of thyroid disease, and she never underwent any neck, thyroid, or parathyroid surgeries. Her most recent laboratory investigations revealed thyroid-stimulating hormone level of 0.93 mIU/ml, free tetraiodothyronine of 0.93 mcg/dl, free triiodothyronine of 2.75 ng/dl, anti-thyroid peroxidase of 2.0 IU/ml, and thyroid-stimulating immunoglobulin of less than 1.0 IU/l. An ultrasound study of her neck revealed an absence of the left thyroid lobe and isthmus. The diagnosis of congenital thyroid hemiagenesis with hypothyroidism was made, and the current treatment with 75 mcg of levothyroxine was continued. Thyroid hemiagenesis is an incidental finding and may present later in life. Thyroid hemiagenesis is commonly associated with hyperthyroidism, but it can present with hypothyroidism. Patients with thyroid hemiagenesis may be at higher risk for developing hypothyroidism than their normal counterparts due to smaller thyroid hormone reserves.

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.

NKX2-5 Variant in Two Siblings with Thyroid Hemiagenesis.

Thyroid hemiagenesis (THA) is an inborn absence of one thyroid lobe of largely unknown etiopathogenesis. The aim of the study was to reveal genetic factors responsible for thyroid maldevelopment in two siblings with THA. None of the family members presented with congenital heart defect. The samples were subjected to whole-exome sequencing (WES) (Illumina, TruSeq Exome Enrichment Kit, San Diego, CA 92121, USA). An ultra-rare variant c.839C>T (p.Pro280Leu) in NKX2-5 gene (NM_004387.4) was identified in both affected children and an unaffected father. In the mother, the variant was not present. This variant is reported in population databases with 0.0000655 MAF (GnomAD v3, dbSNP rs761596254). The affected amino acid position is moderately conserved (positive scores in PhyloP: 1.364 and phastCons: 0.398). Functional prediction algorithms showed deleterious impact (dbNSFP v4.1, FATHMM, SIFT) or benign (CADD, PolyPhen-2, Mutation Assessor). According to ACMG criteria, variant is classified as having uncertain clinical significance. For the first time, NKX2-5 gene variants were found in two siblings with THA, providing evidence for its potential contribution to the pathogenesis of this type of thyroid dysgenesis. The presence of the variant in an unaffected parent, carrier of p.Pro280Leu variant, suggests potential contribution of yet unidentified additional factors determining the final penetrance and expression.

Thyroid hemiagenesis associated with Hurthle cell carcinoma: A case report.

INTRODUCTION AND IMPORTANCE: Thyroid hemiagenesis (TH) is a rare congenital anomaly where one lobe fails to develop, especially more frequently occurs on the left lobe. The exact mechanisms for thyroid morphogenesis remain unclear. In this paper, we report a rare case of right lobe TH associated with Hurthle cell carcinoma. CASE PRESENTATION: A 59 years old woman was admitted with a neck lump increasing in size in the last 20 years. There were no symptoms of hyperthyroidism and hypothyroidism. There was a palpable, painless 5 cm mass in the middle of the neck. Initial thyroid ultrasonography (USG) revealed an enlarged left lobe, with hypoechoic lesion with cystic component and calcification (TIRADS 4). However, the right lobe was non-visualized. Fine needle aspiration biopsy result tendency was a malignancy. Hence, isthmolobectomy was conducted. Pathology result was Hurthle cell carcinoma. On the ninth month, USG revealed fibrotic tissue in the right thyroid bed and bilateral lymphadenopathy. Due to discrepancy, the patient was planned for a neck exploration surgery and a right lobe incision. Intraoperatively, the right thyroid was absent. Intraoperative USG also confirmed no right thyroid lobe. DISCUSSION: Thyroid hemiagenesis can be visualized by using USG due to its practicality and cost effectiveness reasons. Follow up evaluations consisted of systematic monitoring of thyroid morphology and hormonal functions should follow the diagnosis of TH. Neck exploration surgery might need to be performed to clarify any discrepancy and confirm the diagnosis. CONCLUSION: TH can be recognized through supporting examination; however, discrepancy may occur.

Parathyroid Carcinoma in a Patient With Secondary Hyperparathyroidism and Thyroid Hemiagenesis: A Case Report and Review of the Literature.

Parathyroid carcinoma is a rare endocrine tumor. Parathyroid carcinoma in patients with secondary hyperparathyroidism due to chronic kidney disease is also rare. In addition, thyroid hemiagenesis is a rare congenital anomaly. We report an extremely rare case of parathyroid carcinoma in a patient with secondary hyperparathyroidism and thyroid hemiagenesis. We also present a review of the literature of this rare entity. We also discuss the surgical procedure performed for this patient. Our review of the literature found 34 case reports of parathyroid carcinoma in patients undergoing dialysis due to chronic renal failure; 14 reports of thyroid hemiagenesis with parathyroid disease; and no previous reports of thyroid hemiagenesis with secondary hyperparathyroidism and parathyroid carcinoma. Although surgical treatment of parathyroid carcinoma requires combined resection with the thyroid, peritracheal dissection with total parathyroidectomy, and monitoring intact parathyroid hormone as a tumor marker, our procedure preserved the patient's thyroid function. There has been no evidence of recurrence for over 8 years.

Thyroid hemiagenesis with a TI-RADS 2 nodule in the contralateral lobe.

BACKGROUND: Thyroid hemiagenesis is a rare congenital anomaly in which one lobe of the thyroid gland fails to develop. There is an increased incidence of associated thyroid disorders in patients with thyroid hemiagenesis. CASE PRESENTATION: A 32-year-old Ugandan woman presented with a complaint of painless neck swelling of 3-months duration. The swelling was associated with a globus sensation. There was no history of thyroid - related problems or treatment prior to this presentation. Physical examination demonstrated a mobile right thyroid swelling without an obvious nodular contour. Neck ultrasound showed an absent left lobe of thyroid gland, a right lobe with a solitary nodule scoring two points on the Thyroid Imaging, Reporting and Data System (TI-RADS) and an isthmus in situ. Extensive search for possible ectopic thyroid tissue was negative. She was biochemically euthyroid. The patient was counseled about thyroid hemiagenesis and was put on a regular follow up in the clinic for the TI-RADS 2 nodule. CONCLUSION: Thyroid hemiagenesis is often associated with other thyroid disorders. Its diagnosis should prompt an active search for other associated morphological or functional thyroid abnormalities.

Thyroid hemiagenesis with primary hyperparathyroidism or papillary thyroid carcinoma: A report of two cases and literature review.

The combination of TH and PHPT or PTC is extremely rare. A better comprehension of the normal anatomy of the thyroid gland and its variations, congenital anomalies, and related pathologies is essential for safe surgical intervention.

Hemiagenesia tiroidea: caso clínico y revisión de la literatura / Thyroid hemiagenesis: clinical case and review of the literature

La hemiagenesia tiroidea representa un trastorno congénito caracterizado por la ausencia de desarrollo de uno de los lóbulos tiroideos, asociado o no a ausencia del istmo. Es más frecuente en las mujeres y por lo general se presenta como falta del lóbulo izquierdo, con hipertrofia compensatoria del lóbulo contralateral. Su diagnóstico es generalmente incidental o por manifestaciones del lóbulo tiroideo presente. Se hizo una revisión bibliografía, en donde no se encontraron casos reportados en Venezuela de hemiagenesia o agenesia tiroidea, describiéndose el siguiente. Presentamos a una paciente de 50 años de edad, conocida con hipotiroidismo desde los 31 años, negando cualquier cirugía en el área de cabeza y cuello. Desde febrero 2019 presentó aumento progresivo de volumen en región anterior de cuello. Al examen físico se observó aumento de volumen en región anterior derecha del cuello, palpándose lóbulo tiroideo derecho aumentado de tamaño, de aspecto nodular, no doloroso. En ecosonograma tiroideo se concluyó como bocio tiroideo derecho de aspecto multinodular, con ausencia del lóbulo izquierdo. Perfil tiroideo dentro de límites normales. Se lleva a mesa operatoria corroborándose ausencia del lóbulo izquierdo y presentado en la biopsia definitiva hiperplasia nodular en el lóbulo derecho. Se discute su frecuencia, la forma de presentación y se hace revisión de la literatura(AU)

Thyroid hemiagenesis represents a congenital disorder characterized by the absence of development of one of thyroid lobes, associated or not with absence of isthmus. It is more frequent in women and generally presents as absence of the left lobe, with compensatory hypertrophy of the contralateral lobe. Its diagnosis is generally incidental or by manifestations of the present thyroid lobe. A bibliography review was made, where no cases reported in Venezuela of hemiagenesis or thyroid agenesis were found, describing the following. We present a 50-year-old patient, known with hypothyroidism since she was 31, denying any surgery in the head and neck area. Since February 2019, presented a progressive increase in volume in the anterior neck region. On physical examination, an increase in volume was observed in right anterior region of the neck, palpating an enlarged right thyroid lobe, with a nodular appearance and not painful. In a thyroid echo-sonogram, it was concluded as a right thyroid goiter with a multinodular appearance, with the absence of the left lobe. Thyroid profile within normal limits. It is taken to the operating table, confirming the absence of the left lobe and presented in the definitive biopsy nodular hyperplasia in the right lobe. Its frequency, form of presentation, and literature review are discussed(AU)

Compound heterozygous GLI3 variants in siblings with thyroid hemiagenesis.

PURPOSE: Thyroid hemiagenesis (THA) is an inborn absence of one thyroid lobe of largely unknown etiopathogenesis, affecting 0.05-0.5% population. The aim of the study was an identification of genetic factors responsible for thyroid maldevelopment in two siblings with THA. METHODS: We evaluated a three-generation THA family with two sisters presenting the disorder. Proband (Patient II:3) was diagnosed at the age of 45 due to neck asymmetry. Left lobe agenesis and nontoxic multinodular goiter were depicted. Proband's sister (Patient II:6) was euthyroid, showed up at the age of 39 due to neck discomfort and left-sided THA was demonstrated. Affected individuals were subjected to whole-exome sequencing (WES) (Illumina, TruSeq Exome Kit) and all identified variants were evaluated for pathogenicity. Sanger sequencing was used to confirm WES data and check segregation among first-degree relatives. RESULTS: In both siblings, a compound heterozygous mutations NM_000168.6: c.[2179G>A];[4039C>A] (NP_000159.3: p.[Gly727Arg];[Gln1347Lys]) were identified in the GLI3 gene, affecting exon 14 and 15, respectively. According to the American College of Medical Genetics, variants are classified as of uncertain significance, and were found to be very rare (GnomAD MAF 0.007131 and 0.00003187). The segregation mapping and analysis of relatives indicated causativeness of compound heterozygosity. CONCLUSIONS: We demonstrated for the first time a unique association of THA phenotype and the presence of compound heterozygous mutations p.[Gly727Arg];[Gln1347Lys] of GLI3 gene in two siblings.

Thyroid Hemiagenesis and Papillary Carcinoma: a Rare Association.

A 20-year-old female presented with a slowly growing solitary left thyroid nodule for 1 year. USG and CECT neck showed a 4 × 3 cm solid-cystic nodule in the left lobe of thyroid, with notable absence of the right lobe. FNAC from the nodule was Bethesda V. Operative findings confirmed right thyroid lobe agenesis with corresponding absence of right superior thyroid vessels. The right sided RLN, ESBLN, superior and inferior parathyroids, and inferior thyroid vasculature were in their anatomical positions. She underwent standard left hemithyroidectomy. Histopathological examination revealed follicular variant of papillary carcinoma.

Septo-optic Dysplasia with Cerebellar Hemiagenesis.

A 1-month-old girl child, who was found to have hydrocephalus on prenatal ultrasound, was postnatally evaluated with magnetic resonance imaging (MRI) of brain, which showed two classical findings of septo-optic dysplasia (SOD), namely optic nerve hypoplasia and absent septum pellucidum. In addition, the patient was found to have cerebellar hemiagenesis.

Thyroid hemiagenesis: a case report.

Thyroid hemiagenesis is a rare entity in the literature. Developmental hemi-thyroid anomalies can result from either an abnormal descent or an agenesis of one lobe of the thyroid gland. This study aimed at presenting a thyroid hemiagenesis case incidentally diagnosed by neck ultrasonography (USG), who had complaints of pain and swelling in the neck. USG examination revealed lack of left thyroid lobe and multiple nodules in the right lobe. Fine Needle Aspiration Biopsy (FNAB) showed follicular neoplasia, and right subtotal thyroidectomy was performed. We report the rarity of the condition and emphasize the role of imaging techniques in preoperative diagnosis and subsequent management.

Thyroid Hemiagenesis in a Thyroiditis Prone Mouse Strain.

BACKGROUND: Thyroid hemiagenesis, a rare congenital condition detected by ultrasound screening of the neck, is usually not manifested clinically in humans. This condition has been reported in mice with hypothyroidism associated with induced deficiency in paired box 8 and NK2 homeobox 1, sonic hedgehog, or T-box 1. Unexpectedly, we observed thyroid hemiagenesis in NOD.H2h4 mice, an unusual strain that spontaneously develops iodide enhanced thyroid autoimmunity but remains euthyroid. OBJECTIVES AND METHODS: First, to compare mice with thyroid hemiagenesis versus bilobed littermates for serum T4, autoantibodies to thyroglobulin (ELISA) and thyroid peroxidase (TPO; flow cytometry with eukaryotic cells expressing mouse TPO), gross anatomy, and thyroid histology; second, to estimate the percentage of mice with thyroid hemiagenesis in the NOD.H2h4 mice we have studied over 6 years. RESULTS: Thyroid hemiagenesis was observed in 3 of 1,025 NOD.H2h4 mice (2 females, 1 male; 0.3$). Two instances of hemiagenesis were in wild-type females and one in a transgenic male expressing the human TSHR A-subunit in the thyroid. Two mice had very large unilobed glands, as in some human cases with this condition. Thyroid lymphocytic infiltration, serum T4, and the levels of thyroid autoantibodies were similar in mice with thyroid hemiagenesis and bilobed littermates. CONCLUSIONS: Unlike hypothyroidism associated with hemiagenesis in transcription factor knockout mice, hemiagenesis in euthyroid NOD.H2h4 mice occurs spontaneously and is phenotypically similar to that occasionally observed in humans.

Hemiagenesis of thyroid with dual thyroid ectopia: A rare case report.

Developmental defects of the thyroid gland are very rare. The common developmental abnormalities are ectopic thyroid, hemiagenesis and agenesis of thyroid gland. These developmental defects may or may not be associated with deranged thyroid function tests. Ultrasonography (USG) is the initial modality of choice for thyroid hemiagenesis but further evaluation by computed tomography (CT) scan or nuclear scan should be done to look for ectopic thyroid tissue rest. Here, we report a rare case of a 9-year-old female having hemiagenesis of the right thyroid lobe and isthmus along with dual ectopic thyroid tissue at prehyoid and infrahyoid regions of the neck presenting as a midline neck swelling and subclinical hypothyroidism.

Thyroid hemiagenesis and Hashimoto's thyroditis-diagnostic and treatment pitfalls.

BACKGROUND: Thyroid hemiagenesis (TH) is a rare congenital disease with absence of a thyroid lobe; most patients have no clinical symptoms. The etiology of TH remains unclear. In this paper, we describe a rare case of TH and congenital absence of the ipsilateral parathyroid gland, found during the operation, combined with the autoimmune disease Hashimoto's thyroiditis, also known as chronic lymphocytic thyroiditis. CASE PRESENTATION: A 31-year-old woman was admitted to our hospital because of a mass in the right neck. Surgical exploration validated the absence of the left lobe of the thyroid and parathyroid glands, and pathological examination of the excised nodules confirmed Hashimoto's thyroiditis. Patients with TH might show accompanying absence of the ipsilateral parathyroid gland. The case described here, in which TH was combined with Hashimoto's thyroiditis, is rare in the medical literature. The operation should be ended at once if Hashimoto's thyroiditis is diagnosed during surgery. CONCLUSIONS: Absence of thyroid lobe may accompany with a congenital absence of the ipsilateral parathyroid gland and Hashimoto's thyroiditis. Fine needle aspiration is essential to diagnosis and decision-making of the treatment.

Prevalence and Characterization of Thyroid Hemiagenesis in Japan: The Fukushima Health Management Survey.

BACKGROUND: Thyroid hemiagenesis is a rare congenital variant characterized by the lack of development of one thyroid lobe with no clinical manifestations. METHODS: This study was performed to determine the prevalence and characteristics of thyroid hemiagenesis in a normal Japanese population. This cross-sectional study was performed from October 9, 2011, to April 30, 2015. In total, 299,908 children and young adults in the Fukushima Health Management Survey were examined to determine the presence of thyroid agenesis or hemiagenesis. Thyroid width, thickness, and length were measured in 292,452 of these subjects. RESULTS: Thyroid agenesis was diagnosed in 13 subjects, and hemiagenesis was detected in 67 subjects (0.02%; 22.3/100,000 individuals). Although there was no significant sex-related difference (p = 0.067), the female:male ratio was 1.67:1.00. Females were significantly dominant in right hemiagenesis, while there was no difference in left hemiagenesis between males and females. The thyroid volumes at the 2.5th and 97.5th percentiles for age and body surface area were determined for each sex. Multivariate regression analysis showed that a large hemithyroid volume was independently associated with the presence of contralateral hemiagenesis (p < 0.001). CONCLUSION: The prevalence of thyroid hemiagenesis in the present study is in agreement with that reported in other countries. The prevalence of right hemiagenesis was higher in females, and the larger contralateral lobe in patients with rather than without hemiagenesis may have been caused by a compensatory feedback mechanism to prevent hypothyroidism. In addition, the prevalence of hemiagenesis, especially right hemiagenesis, may be affected by sex-related factors similar to those in patients with an ectopic thyroid gland.