The thyroid gland develops from the endodermal tissues of the primitive gastrointestinal tract. The site of origin ultimately is the foramen caecum at the tongue base and descent of the thyroid by the seventh gestational week to lie anterior to the cricoids and cervical trachea.
The descent of the thyroid through the anterior midline neck explains several anomalies that relate to thyroid pathology. Along the pathway of thyroid descent, a cyst of ciliated pseudostratified epithelium and variable amounts of thyroid tissue may remain which is called thyroglossal duct cysts [
The thyroid gland descends from the foramen cecum to the point below the thyroid cartilage by the seventh week of the intrauterine life. Thyroglossal duct is the epithelial connection between the thyroid gland and the foramen caecum. In the 8th to 10th week of gestation, this duct is normally obliterated. If a complete involution is failed, the remaining epithelium can develop a cystic expansion and form a thyroglossal duct cyst (TDC). TDC is the most common congenital anomaly in thyroid development and occurs in 7% of the adult population [
A 57-year-old man presented to the oncology outpatient clinic with a year history of an enlarging right anterior neck mass and an enlarging midline neck mass since the last four months before admission. He was in a good health. On physical examination, there were a 5 × 3 × 2 cm firm mass on the right anterior part of the neck which is mobile with swallowing and a 6 × 5 × 5 cm soft tender cystic mass on the midline anterior (Figure
Clinical presentation of the patient.
A cervical ultrasound showed an irregular heterogenous echoic mass lesion which appeared to be a TDC and a left multinodular goiter.
A cervical computed tomography (CT) showed a 6.24 × 4.53 × 6.57 cm heterogeneous calcified mass in the right anterior region of the neck extending to intrathoracic area and pushing the trachea to the left; a calcified left thyroid nodule measuring 0.73 cm in diameter; a 3 × 4 × 3.5 cm heterogenous mass destructing the hyoid bone which appeared to be malignancy; and a 7 × 9 × 5 cm septated cystic structure in the midline anterior of the neck (Figure
Axial and transverse section of a CT of the neck.
At the presurgery stage, the lesions were diagnosed as a thyroglossal duct cyst (TDC) and a nontoxic multinodular goiter. Total thyroidectomy and Sistrunk procedure were performed to remove the tumor mass in TDC. The TDC tumor mass has already infiltrated the surrounding tissue so we performed debulking surgery and left very small remnant that was attached to the laryngeal mucosa.
At the postsurgery stage, the lesions were diagnosed as a papillary thyroid carcinoma “tall cell” variant arising in the TDC and both of the right and left (Figure
Papillary carcinoma “tall cell” variant evolving from a thyroglossal duct cyst (H&E).
The patient was treated with radioactive iodine ablation. The patient refused a follow-up visit after the radio iodine ablation; thus, we were unable to measure the thyroglobulin level in this patient.
A 35-year-old woman presented with a lump at the anterior of her neck one month before admission, with no other complaints. Physical examination revealed a 3 × 3 × 3 firm mass with well-defined border which is mobile with swallowing. Laboratory investigation revealed no abnormalities.
At the presurgery stage, the lesions were diagnosed as a thyroglossal duct cyst (TDC) and the patient underwent a Sistrunk procedure to remove the lump.
At the postsurgery stage, the lesions were diagnosed as a papillary thyroid carcinoma. Thus, a total thyroidectomy was performed. A cervical ultrasound conducted before total thyroidectomy showed multiple small nodules in both lobes with calcifications and laboratory investigations were in normal range.
Postsurgery pathological examination of the mass obtained from the total thyroidectomy revealed papillary thyroid carcinoma. The patient refused a follow-up visit after the surgery; thus, the radioactive iodine ablation was not done. We were unable to measure the thyroglobulin level for this patient.
A clinician should do a systematic approach when dealing with a neck mass since it is a common clinical finding that has extremely broad differential diagnosis. Most of the cases are due to benign process but clinician should be aware of malignant disease.
Thyroglossal duct is the epithelial connection between the thyroid gland and the foramen cecum. Normally, the duct will involute completely at the 8th to 10th week of gestation. The failure of this process causes the remaining epithelium to lead to the development of a thyroglossal duct remnants, most typically cysts [
The etiology of the papillary carcinoma arising in a TDC is unclear but, generally, there are two theories which can explain this phenomenon, de novo origin and spread from a primary thyroid gland tumor [
Strict criteria for TDC carcinoma diagnosis suggested by Mesolella et al. include a thyroglossal remnant, ectopic thyroid nests within the cyst wall, and a clinically normal thyroid gland [
The main difficulties faced in dealing with a carcinoma appearing in a TDC are the diagnosis and the management of this entity. Malignant TDCs are commonly mistaken from benign TDCs because of the indistinguishable mass presence at the anterior neck. Preoperative evaluation of thyroglossal duct cyst includes head and neck examination, palpation of thyroid gland, and imaging techniques. Malignancy cannot usually be diagnosed preoperatively by imaging diagnostic techniques (ultrasound, scintigraphy, and CT) [
Beside the difficulties encountered in the diagnosis, clinicians also faced much of controversy regarding the surgical treatment arising in a TDC. Because TDC carcinoma is a rare case and lacks preoperative diagnosis, in addition to the possibility of associated thyroid malignancy, there is lack of consensus in the literature regarding the optimal management for TDC carcinoma [
Another difficulty we faced in Indonesia is a financial problem. Although public health insurance in Indonesia covers most of medical procedures, patients are still unable to afford another expenditure, such as transportation cost from their home to the hospital. This financial problem became the reason why the thyroglobulin level was not measured for both patients and the radioactive iodine ablation was not done for the second patient.
The surgical procedure performed commonly for a thyroglossal duct cyst is a surgery called Sistrunk’s procedure. This procedure consists of removal of the thyroglossal duct cyst, the medial segment of the hyoid bone, and a core of tissue around the duct to open into the oral cavity at the foramen cecum. Although some surgeons consider the Sistrunk’s procedure to be adequate if histological examination does not show extracystic extension [
When the definitive histological analysis reveals malignancy after Sistrunk procedure to remove TDC, the thyroid gland must be studied further with radiological and scintigraphic examinations [
A total or subtotal thyroidectomy has been recommended if there is cystic wall invasion by the carcinoma or if the TDC carcinoma is greater than 1.5 cm [
A previous study reported that papillary carcinoma in TDC has the same similarities with general papillary carcinoma, including the similarity in terms of lymph node metastasis [
The prognosis for papillary TDC carcinoma is excellent, with occurrence of metastatic lesions in less than 2% of cases [
Formation of thyroid carcinoma in a TDC is very rare. Surgeons must be aware and include this entity while examining a patient with a neck mass especially located around hyoid bone [
Patients’ written informed consent was obtained for publication.
The authors declare no conflict of interests.