|Year : 2016 | Volume
| Issue : 2 | Page : 74-76
Right lobar hemiagenesis with ectopic thyroid: A case report of a very rare entity
Anil Taneja1, Sonal Sethi1, Bindu Kulshreshtha2, Imroz Sachdev1
1 Department of Radiodiagnosis, Post Graduate Institute of Medical Education and Research and Dr. Ram Manohar Lohia Hospital, New Delhi, India
2 Department of Endocrinology, Post Graduate Institute of Medical Education and Research and Dr. Ram Manohar Lohia Hospital, New Delhi, India
|Date of Web Publication||1-Jun-2016|
Dr. Sonal Sethi
20, Kalyan Vihar, Polo Road, New Delhi - 110 009
Source of Support: None, Conflict of Interest: None
Developmental morphological abnormalities of the thyroid gland are very rare. Thyroid lobe hemiagenesis is a very rare abnormality, in which one thyroid lobe fails to develop. Ectopic thyroid is one of the common developmental anomalies of thyroid characterized by the presence of thyroid tissue in a site other than its usual. Of all, lingual thyroid is the most common manifestation of benign ectopic thyroid tissue, but it is still a rare clinical entity. Both of them seen together is even rarer. These developmental defects may or may not be associated with thyroid dysfunction. 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 other thyroid ectopic tissue rest. We report a case of right thyroid hemiagenesis with ectopic lingual thyroid in a 13-year-old female. To the best of our knowledge, only two similar cases in the world literature have been reported till date.
Keywords: Ectopic, hemiagenesis, lingual: usg, ncct, thyroid
|How to cite this article:|
Taneja A, Sethi S, Kulshreshtha B, Sachdev I. Right lobar hemiagenesis with ectopic thyroid: A case report of a very rare entity. Thyroid Res Pract 2016;13:74-6
|How to cite this URL:|
Taneja A, Sethi S, Kulshreshtha B, Sachdev I. Right lobar hemiagenesis with ectopic thyroid: A case report of a very rare entity. Thyroid Res Pract [serial online] 2016 [cited 2020 Apr 1];13:74-6. Available from: http://www.thetrp.net/text.asp?2016/13/2/74/157919
| Introduction|| |
Thyroid developmental anomalies can be divided into three major groups, namely agenesis, dysgenesis, and anomalies due to persistence of the thyroglossal tract. Hemiagenesis is a form of thyroid dysgenesis, in which one thyroid lobe fails to develop, along with or without of the isthmus of the gland. Prevalence of hemiagenesis of thyroid is variable from 0.05% to 0.2%.,, The left lobe of the thyroid gland is involved in approximately 80% of thyroid hemiagenesis., The isthmus is absent in approximately 50% cases of thyroid hemiagenesis. Both hemiagenesis and ectopic thyroid is more common in women, due to the prevalence of thyroid diseases in females. Ectopic thyroid tissue is an entity that is characterized by the presence of thyroid tissue in locations other than its usual pre-tracheal location. It is commonly situated in the base of the tongue but can be present in the midline, along the thyroglossal duct. Prevalence of ectopic thyroid tissue from post-mortem studies shows that ectopic thyroid tissue is seen 7-10% of adults, along the path of the thyroglossal duct.
We report a case of right lobar hemiagenesis with concurrent ectopic lingual thyroid tissue. Only two similar case reports have been reported in the world literature to the best of our knowledge.
| Case Report|| |
A 13-year-old female presented with a neck swelling on the left side of the neck. There was no history of heat intolerance, palpitations, weight loss, tremulousness, or menstrual disturbances. The patient did not complain of dysphagia or dyspnea. There was no history of neck surgery or irradiation in the past. Clinical examination of the neck was done which showed a firm swelling in the left side of the neck. It also revealed that the left lobe of the thyroid was palpable whereas no thyroid tissue was felt on the right side. Systemic examination was normal. Then the patient was subjected to further evaluation.
Ultrasonography (USG) of the neck showed the swelling to be an enlarged lymph node in the left lower jugular region, which showed reactive hyperplasia on Fine Needle Aspiration Biopsy (FNAB). USG examination also revealed mildly enlarged left lobe of thyroid, with normal echotexture and vascularity measuring 2.2 × 2 × 5 cm, with absent right lobe suggesting the possibility of right lobar hemiagenesis of thyroid. The isthmus was present and measured 4 mm (anteroposteriorly) in size and had normal vascularity [Figure 1]a, [Figure 1]b. No ectopic thyroid tissue was seen on USG. Thereafter, the patient underwent Non-Contrast Computed Tomography (NCCT) scan, which not only confirmed the USG findings of absence of right lobe of thyroid with normal left lobe of thyroid and isthmus but also revealed an ectopic focus of thyroid in the lingual region [Figure 2]a, [Figure 2]b, [Figure 2]c, [Figure 2]d, [Figure 2]e. The thyroid nuclear scan corroborated these findings with avid uptake in a pattern consistent with right thyroid lobe hemiagenesis as well as an ectopic lingual focus of thyroid [Figure 3]. Thyroid function test was done thereafter, which showed elevated TSH (11.26 uIU/ml), normal free T3 (4.00 pg/ml), and T4 (1.27 ng/dl) levels. Therefore, a final diagnosis of hemiagenesis of the right lobe of the thyroid with concurrent ectopic lingual thyroid tissue along with subclinical hypothyroidism was made. The patient was started on thyroxine 25 mg once daily. On follow-up, the patient was asymptomatic and thyroid function test became normal.
|Figure 1: (a) Transverse USG scan of neck shows absent right thyroid lobe (red astrix) with presence of isthmus and left lobe of thyroid (yellow astrix), (b) Transverse Doppler USG scan of neck shows the presence of only left throid lobe with isthmus with normal vascularity|
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|Figure 2: (a) Axial NCCT Scan of neck at cricoid level shows absent right thyroid lobe and visualisation of normal left lobe (yellow arrow) and isthmus of thyroid gland (red arrow) (b) Axial NCCT Scan at the level of tongue shows hyperdense ectopic thyroid tissue at the base of tongue (yellow arrow) (c) Reformatted Coronal view of NCCT Scan of neck at cricoid level shows absent right thyroid gland and visualisation of normal left lobe and isthmus of thyroid gland (yellow arrow) (d) Reformatted Coronal view of NCCT Scan shows hyperdense ectopic thyroid tissue at the base of tongue (yellow arrow) (e) Reformatted sagittal view of NCCT Scan shows ectopic thyroid tissue(red arrow) and left thyroid lobe (yellow arrow)|
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|Figure 3: Thyroid nuclear scan shows normal uptake in left lobe (yellow arrow) and isthmus (blue arrow) of thyroid and no uptake on right side. Additional focus of uptake is seen at base of tongue (red arrow)|
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| Discussion|| |
The thyroid gland is the first endocrine gland to develop in an embryo around 4-5 weeks of gestation. It starts as a median endodermal pouch in the floor of pharynx and develops into a diverticulum later. This grows ventrally and caudally to lie anterior to pharynx. Then, it grows laterally to form the lateral lobes and isthmus.,
Thyroid gland development passes through many stages of migration, descent, and lobulation, which are being controlled by various genetic and hormonal factors. Mutations in these factors are postulated to be responsible for thyroid dysgenesis; however, the exact etiology is not still clear.,,,
Dysgenesis can be in the form of hemiagenesis of the thyroid or as an ectopic thyroid or rarely seen as a concurrent finding. Only two more similar cases of right-sided hemiagenesis with ectopic lingual thyroid has been reported in world literature till date., The clinical presentation of thyroid hemiagenesis is variable. It has been reported as an incidental finding either due to a pathology affecting the other lobe or any other neck pathology as in our case. Patients may have a normal thyroid lobe with euthyroidism, hypothyroidism, or even hyperthyroidism. Thyroid function is seen as abnormal in 38-47% of patients as in our case.
Our patient presented with swelling in the neck, and the diagnosis was incidentally made with USG of neck. For further assessment, NCCT neck was done as thyroid appears hyperdense even on non-enhanced scans due to high iodine content. Cross-sectional imaging also helps in localizing the other foci of thyroid tissue if present as in our case. Thyroid scintigraphy using technetium or iodine is helpful but could be misleading sometimes as many pathologies lead to non-visualization of one thyroid lobe-like neoplasm, contralateral autonomous solitary thyroid nodule that is suppressing normal tissue, inflammatory, and infiltrative diseases of the thyroid. Therefore, scintigraphy findings should be correlated with the findings of ultrasound and cross-sectional imaging. On follow-up scans, the main concern is to rule out the malignancy and follow the thyroid hormone levels.
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[Figure 1], [Figure 2], [Figure 3]