|Year : 2020 | Volume
| Issue : 2 | Page : 86-88
Left thyroid agenesis case study
Bayan Osama Besharah1, Haddad Hussin Al-Kaf2, Sherif Kamel Abdelmonim3, Mohammad Ali Al-Essa2
1 Department of Head, Neck and Skull Base Center, King Abdullah Medical City, Mecca; Department of Otolaryngology Head and Neck Surgery, King Fahad Armed Force Hospital, Jeddah, Saudi Arabia
2 Department of Head, Neck and Skull Base Center, King Abdullah Medical City, Mecca, Saudi Arabia
3 Department of Head, Neck and Skull Base Center, King Abdullah Medical City, Mecca; Department of Otolaryngology Head and Neck Surgery, Factuality of Medicine, Ain Shams University, Cairo, Egypt
|Date of Submission||17-Feb-2020|
|Date of Decision||12-Mar-2020|
|Date of Acceptance||25-Mar-2020|
|Date of Web Publication||30-Dec-2020|
Dr. Mohammad Ali Al-Essa
Head, Neck and Skull Base Center, King Abdullah Medical City Hospital, Mecca
Source of Support: None, Conflict of Interest: None
Thyroid hemiagenesis is a rare congenital anomaly, more commonly affecting the left lobe of the thyroid. There is only one case reported in Saudi Arabia in Annals Saudi journals 1997, and this will be the second case to be reported in Saudi. Here, we present a 67-year-old woman with the left thyroid lobe agenesis and multinodular goiter in the right thyroid lobe. The condition was discovered during preoperative preparation for tracheostomy, which showed euthyroid (in laboratory measurements) and an enlarged right large thyroid lobe extending up to cervical vertebra 2 and the retrosternal area (in computed tomography images). The patient underwent total thyroidectomy and tracheostomy. Postoperative thyroid scan and histopathology results confirmed the diagnosis. It is a rare anomaly, with most patients asymptomatic. Consequently, cases may not be readily diagnosed.
Keywords: Case study, thyroid agenesis, thyroid hemiagensis, thyroid hemiaplasia, thyroid malformation, unilateral thyroid
|How to cite this article:|
Besharah BO, Al-Kaf HH, Abdelmonim SK, Al-Essa MA. Left thyroid agenesis case study. Saudi J Otorhinolaryngol Head Neck Surg 2020;22:86-8
|How to cite this URL:|
Besharah BO, Al-Kaf HH, Abdelmonim SK, Al-Essa MA. Left thyroid agenesis case study. Saudi J Otorhinolaryngol Head Neck Surg [serial online] 2020 [cited 2021 Jan 17];22:86-8. Available from: https://www.sjohns.org/text.asp?2020/22/2/86/305465
| Introduction|| |
The thyroid gland is the first endocrine organ to begin to develop in the embryo. It is derived from the endoderm of the pharyngeal floor between the first and second branchial pouches and can be seen developing between the branchial pouches by day 20 following conception. By the 4th week of gestation, a median diverticulum forms and subsequently descends lower in the neck to its position ventral to the trachea as a bifurcating tubular duct. These ducts become the isthmus and lateral lobes. During this development process, the thyroid anlage is still connected to the pharyngeal floor by the thyroglossal duct, which disappears later by the 5th week of gestation. Any developmental abnormality in this embryonic process can lead to gland anomaly.,
Frequently, the thyroid gland is asymmetrical in size, with the right lobe often larger than the left lobe. Thyroid hemiagenesis (THA) is a rare congenital anomaly defined as the absence of development of one thyroid lobe with or without development of the thyroid isthmus., Most cases are discovered incidentally, because the case is referred for the evaluation of a neck mass or in the course of imaging for the investigation of unrelated diseases.,, The first case in Saudi Arabia was reported in 1997 by Alam. Here, we present a second case.
| Case Report|| |
A 67-year-old Burmese female admitted through the emergency department under the care of internal medicine for septic shock and myocardial infarction, had been intubated for ≥3 weeks. Due to the lack of improvement in her condition and the expectation of a prolonged period of intubation, a tracheostomy was planned. At the initial intubation, medical history was taken from the patient's family. There was no history of previous thyroid disease or surgery or radiation to the neck region. They did not give any history of dyspnea or compressive symptoms. Her medical history was not statistically significant with regard to thyroid status.
On physical examination, the patient was intubated with an endotracheal tube connected to a mechanical ventilator. She was a 7/10 on the Glasgow Coma Scale and had stable vital signs. A large neck swelling was present, occupying the right lateral side and crossing the midline trachea. The swelling was nodular and firm on palpation, and there were no palpable cervical lymph nodes.
Her thyroid function test was 0.003 mI U/L with normal circulating levels of thyroxine and triiodothyronine. Computed tomography (CT) of the neck showed significant enlargement of the thyroid gland with the right lobe extending superiorly to the level of the second cervical vertebra (C2) and inferiorly to the retrosternal region [Figure 1]. In addition, the enlarged gland contained multiple densely calcified foci. In the CT images, the transverse anterior-posterior measurement of the thyroid gland was approximately 6 cm, and the craniocaudal measurement was approximately 12 cm. Fine-needle aspiration cytology of the right thyroid nodule showed aggregates of benign follicular cells.
|Figure 1: Computerized scan of the neck showing enlargement of the right thyroid lobe. The enlarged lobe extends superiorly to the level of the second cervical vertebra and inferiorly to the retrosternal area. The isthmus and left thyroid lobe were not seen|
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The patient underwent surgery for the thyroid to enable access for the tracheostomy. The neck was explored by the standard thyroid incision. Intraoperative findings confirmed the presence of a unilateral right thyroid lobe and isthmus with multiple firm nodules and the absence of a left thyroid lobe [Figure 2]. The bilateral recurrent laryngeal nerve with a normal anatomical course was present, and the right superior and inferior parathyroid glands were seen. Histopathological examination showed benign multinodular colloid goiter. Specimen measurement of the excised right thyroid lobe was 10 cm × 5.5 cm × 4.5 cm [Figure 2]. The postsurgical recovery was unremarkable.
|Figure 2: Right thyroid lobe specimen showing the absence of the isthmus and left thyroid lobe|
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After surgical recovery, a scintigraphic thyroid scan was performed to exclude the possibility of abnormally located thyroid tissue. No evidence of ectopic thyroid tissue was present in the scan [Figure 3].
|Figure 3: Postoperative thyroid scan showing no definite scintigraphic of residual thyroid in the thyroid bed or ectopically. Left image shows uptake on salivary glands (*) and parotid tail (**) with no thyroid bed uptake; Sternal notch indicated in the right image|
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| Discussion|| |
THA is an uncommon congenital abnormality, first described by Handsfield-Jones in 1966. It is difficult to estimate the true incidence because most patients are asymptomatic and functionally normal: the contralateral thyroid lobe provides a sufficient production of the gland's hormones., Based on the reported cases, the prevalence of THA ranges from 0.05% to 0.5%. Between 1970 and 2010, ~329 cases were reported with ~80% of cases missing the left thyroid lobe, followed by 44%–50% with isthmus agenesis. Our case of a female with left THA is similar to this majority of cases.
Although one study reported a female predominance with a female-to-male ratio of 7:1, this may relate to the higher incidence of thyroid disease in women, which make them more likely to be clinically evaluated. Indeed, another study of healthy schoolchildren screened for developmental abnormalities of the thyroid reported a male-to-female ratio of 1.4:1.0. Due to the low frequency of diagnosed THA and the lack of presenting symptoms, the association between THA and other conditions is unclear. However, some studies and individual cases suggest that there may be some connections. Some studies reported THA presenting with parathyroid gland disorder, in particular, primary hyperparathyroidism. The cases included THA with ipsilateral or contralateral parathyroid adenoma (single or double adenoma) and parathyroid hyperplasia.
In addition, Sakurai et al. showed a case of right THA with the ipsilateral absence of the upper and lower parathyroid glands with the left inferior parathyroid adenoma. In our case, superior and inferior parathyroid glands were seen on the ipsilateral side to the THA, but the glands could not be seen on the contralateral side due to the huge thyroid size. We also observed normal bilateral recurrent laryngeal nerve, which is consistent with the lack of reported THA cases with recurrent laryngeal nerve abnormality. Nakamura et al. reported a patient with dual ectopic thyroid glands in the lingual and infrahyoid regions and the left THA and right thyroid atrophy, suggesting a connection between THA and ectopic thyroid. Sato et al. showed that there is a risk of thyroid cancer in patients with THA.
Most THA cases are discovered incidentally while investigating lesions in the neck region or the other thyroid lobe.,, Moreover, patients are usually asymptomatic and functionally euthyroid, although some cases are associated with abnormal levels of thyroid hormones, either hypothyroidism or hyperthyroidism. Thus, physical examination often provides the first evidence of possible THA. The presence of the following physical examination is possible indicators of THA: a palpable trachea edge, medialization of the sternocleidomastoid muscle edges on the affected side, or abnormal palpable tissue that overlies the trachea.,
During the clinical evaluation for THA, thyroid scintigraphy with technetium or iodine will show a feature called the “hockey stick” when the thyroid isthmus is present. However, this test is inconclusive because disease of the contralateral thyroid lobe, such as thyroid toxic adenoma, inflammatory infiltrative disease or malignancy, can be misinterpreted as THA (a false-positive result).,
Ultrasonographic examination is the preferred modality for the initial diagnosis because this technique can reliably indicate the presence or absence of thyroid lobes. If a lesion is suspected, the thyroid imaging reporting and data system provides a guideline for treatment.,, Unfortunately, ultrasound of the neck could not be done in our case because of the patient's clinical condition in the intensive care unit with multiple peripheral and central lines connected to neck vessels.
The final diagnosis in our case was left THA with right benign multinodular goiter. To our knowledge, our case represents only the second case in Saudi Arabia since the case reported by Alam in 1997.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the legal guardian has given his consent for images and other clinical information to be reported in the journal. The guardian understands that names and initials 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]