|Year : 2019 | Volume
| Issue : 2 | Page : 80-83
Travesty of a thyroglossal cyst – A clinical scenario
Basavaraj P Belaldavar1, Vikrant B Ghatnatti2, Manali Ramana Bhat3
1 Department of ENT, Jawaharlal Nehru Medical College, KLES Dr Prabhakar Kore Hospital, Belagavi, Karnataka, India
2 Department of Medicine, KLES Dr Prabhakar Kore Hospital, Belagavi, Karnataka, India
3 Department of ENT, Jawaharlal Nehru Medical College, Belagavi, Karnataka, India
|Date of Web Publication||15-Jul-2019|
Dr. Manali Ramana Bhat
Room No. 120, Ladies PG Hostel, JNMC Campus, Belagavi - 590 010, Karnataka
Source of Support: None, Conflict of Interest: None
A 14-year-old girl presented to the outpatient department with a midline neck swelling, clinically suspected to be a thyroglossal cyst. Routine ultrasonography of the neck showed the absence of thyroid gland in its anatomical position and the presence of lingual thyroid with multiple cystic changes. Computed tomography revealed an infrahyoid and lingual dual ectopic thyroid with the absence of thyroid in its normal anatomical location. Tc-99m pertechnetate confirmed the diagnosis of dual ectopic thyroid. Thus, ectopic thyroid, though rare, must be considered as a differential diagnosis for a thyroglossal cyst.
Keywords: Dual ectopic, ectopic thyroid, Tc-99m pertechnetate, thyroglossal cyst
|How to cite this article:|
Belaldavar BP, Ghatnatti VB, Bhat MR. Travesty of a thyroglossal cyst – A clinical scenario. Thyroid Res Pract 2019;16:80-3
| Introduction|| |
Ectopic thyroid is a developmental abnormality characterized by the presence of thyroid tissue in any location other than its normal anatomic position. It was first reported by Hickman in 1869. It is more common in females, with the ratio being 3–4:1. Lingual ectopic accounts for 70%–90% of all cases with clinical incidence between 1:4000 and 1:10,000. Simultaneous presence of two ectopic foci of thyroid tissue is rare, and very few such cases have been reported, with a female preponderance of 1.5:1. In most cases, the normal thyroid gland is absent. We report a case of dual ectopic thyroid, clinically suspected to be a thyroglossal cyst, and its management.
| Case Report|| |
A 14-year-old girl presented to our outpatient department with a painless midline neck swelling for the past 2 years, insidious in onset, gradually progressive. She was clinically euthyroid, with no other complaints. On examination, there was a solitary ovoid swelling, 3 cm × 4 cm in the midline of the upper third of the neck. The swelling moved with deglutition and protrusion of the tongue, analogous to a thyroglossal cyst [Figure 1]. However, it was unusually firm in consistency and nontransilluminant. Her oral cavity and oropharynx were normal.
|Figure 1: Movement of swelling with (a) on deglutition, (b) on protrusion of tongue|
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The patient underwent ultrasonography of the neck, which showed the absence of thyroid gland in its normal anatomical position, with a lingual thyroid with multiple cystic changes. Computed tomography (CT) scan of the neck with contrast revealed a fairly well-defined heterogeneously enhancing mass with few hypodense areas in the infrahyoid region, in the midline, within the pretracheal fascia, measuring 3 cm horizontally × 2.4 cm craniocaudally × 1.8 cm anteroposteriorly, opposite C3–C5 vertebral bodies. Ironically, another mass was detected, which was homogenously enhancing, measuring 0.9 cm anteroposteriorly × 1 cm horizontally × 1.2 cm craniocaudally, located at the base of the tongue [Figure 2]. Contrast CT affirmed the absence of thyroid gland in its anatomical position and, thus, the diagnosis of dual ectopic thyroid.
|Figure 2: Contrast computed tomography showing infrahyoid ectopic in a and c (arrow), ectopic tissue at the base of the tongue in b and c (dotted arrow)|
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She was found to be hypothyroid as well, with the hormonal levels as follows: free T3 – 4.54 pg/mL, free T4 – 0.73 ng/dL, and thyroid-stimulating hormone (TSH) – 24.55 μIU/mL.
Tc-99m pertechnetate scan showed no tracer uptake in normal anatomical thyroid bed, but showed two separate foci of activity, that is, one in the midline in the upper neck and the other in the base of the tongue, suggesting that ectopic tissues at both these sites were functional [Figure 3].
|Figure 3: Tc-99m pertechnetate scan showing two foci of activity, with no uptake in thyroid bed|
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The patient was started on tablet levothyroxine 75 μg OD as per the endocrinologist's advice. Thyroid function tests were repeated after 2 months and were within normal limits. Furthermore, the size of thyroid swelling decreased significantly after 4 months of therapy [Figure 4].
|Figure 4: Significant reduction in size of swelling after 4 months of thyroid hormone replacement therapy|
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| Discussion|| |
The thyroid gland develops from a thickening of the endodermal epithelium in the foregut between the first and second branchial arches at the base of the tongue. The cells proliferate to form the thyroid bud and then a diverticulum, which expands and migrates from the base of the tongue to lie anterior to the trachea.
Arrest in descent occurs most commonly just below the foramen cecum, resulting in a lingual ectopic, or sometimes between geniohyoid and mylohyoid muscles, resulting in a sublingual ectopic, or just above and below the level of the hyoid bone. To our knowledge, 63 cases of dual ectopic thyroid have been reported, with age range being 11 days to 75 years.
Although ectopic thyroid is a congenital anomaly, it may present at any age, usually during puberty or pregnancy. Alt et al. stated that heterotopia due to aberrant migration has inadequate blood supply and is not able to release a sufficient amount of hormones. This leads to increased TSH and goitrous enlargement of the ectopic thyroid tissue. About half of the patients with dual ectopic are euthyroid, and the rest are hypothyroid.
Patients with lingual ectopic may be asymptomatic or may present with dysphagia, dysphonia, stomatolalia, cough, foreign body sensation, snoring, sleep apnea, respiratory obstruction, or hemorrhage. The patient was asymptomatic, and the lingual ectopic was not clinically evident. This added to difficulty in clinical diagnosis.
Scintigraphy, using Tc-99m, I-131, or I-123, is an important diagnostic tool to detect the presence or absence of thyroid in its normal location and to unmask additional sites of thyroid tissue. It is both sensitive and specific for differentiation of an ectopic thyroid from other causes of midline neck masses such as thyroglossal cyst, lipoma, or enlarged lymph node. It also helps differentiate a lingual thyroid from other swellings in the base of the tongue such as hypertrophic lingual tonsil, vallecular cyst, and mucus retention cyst.
There is no consensus about the optimal therapeutic strategy, perhaps due to the rarity of this clinical entity. Most authors agree that surgical treatment of ectopic thyroid in the neck depends on patient's age, functional thyroid status, size of the ectopic and its local symptoms (airway obstruction, dysphagia, and dysphonia), and complications of the mass (ulceration, bleeding, cystic degeneration, or malignancy). Some recommend complete surgical resection, considering the potential of malignant transformation. The rates of malignant transformation in ectopic and eutopic thyroid tissue are similar, with most common histopathological subtype being follicular in lingual ectopic, papillary carcinoma at other sites. For asymptomatic euthyroid patients, regular follow-up is recommended to detect mass enlargement or development of complications. For hypothyroid patients with mild symptoms, levothyroxine replacement therapy may lead to considerable mass reduction.
As our patient was hypothyroid with no evidence of complications of the ectopic tissue, with a significant decrease in size of neck swelling after commencement of levothyroxine replacement therapy, conservative approach with regular follow-up was advised.
| Conclusion|| |
With this case study, we would like to propose that ectopic thyroid, though rare, must be considered as a differential diagnosis for a thyroglossal cyst. Primarily, ultrasonography is a must to locate the thyroid gland in its normal position. If dual ectopic thyroid tissue is suspected, thyroid function should be evaluated by thyroid uptake scan and thyroid hormone estimation. Thus, one can have a decisive evaluation, which, in turn, will help have protocolled management of such cases.
A high index of suspicion for ectopic thyroid tissue is essential to avoid unnecessary surgery and resection of functional ectopic thyroid tissue with consequent hypothyroidism.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient's father has given his consent for patient's images and other clinical information to be reported in the journal. The patient's father understands that name and initials of the patient will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]