A Rare Case Report of Thyroglossal Duct Cyst Carcinoma Coexisting with Thyroid Carcinoma in an Adolescent

Background

Thyroglossal duct cysts (TDC) represent approximately 70% of all congenital neck masses, and up to 1% of them contain thyroid tissue malignancies. Clinical presentation of TDC carcinomas is usually indistinguishable from benign tumors preoperatively, and differential diagnosis can be challenging. We present a rare case of TDC carcinoma concurrent with thyroid cancer in an adolescent. Case Presentation. A 16-year-old Caucasian female, otherwise healthy, was referred with a painless, gradually expanding lump on the neck. Physical examination revealed a well-circumscribed, moderately hard, tender mass of the anterior neck midline anteroinferior to the hyoid bone. Imaging findings suggested TDC as the most likely diagnosis. The patient had a Sistrunk procedure under general anesthesia. Histopathological findings diagnosed a BRAFV600E-positive papillary thyroid carcinoma (PTC) in a TDC. A thyroid gland and neck ultrasound revealed a highly suspicious finding for malignancy right level VI lymph node, which was not confirmed by fine needle aspiration cytology (FNAC). Under general anesthesia, total thyroidectomy and central compartment lymph node neck dissection were performed. Histopathological findings revealed a thyroid parenchymal locus of PTC, as well as three lymph nodes infiltrated by PTC. The patient received adjuvant radioactive iodine ablation (RAI) therapy and is closely followed.

Conclusion

TDC carcinomas in conjunction with thyroid carcinomas in young patients are rare. Preoperative diagnosis can be challenging, as the vast majority of neck masses in young patients are benign in nature, and most malignant tumors lack specific clinical features. The diagnostic accuracy of FNAC is considered unsatisfactory due to its frequently cystic nature. Definitive diagnosis is based on histopathological findings. Clinicians should maintain a high level of suspicion for coexisting thyroid malignancies. Although surgical extirpation of the malignancy is considered standard of care, the treatment of TDC cancer should always be individualized by a multidisciplinary team.

Thyroglossal Duct Cyst Papillary Carcinoma With Airway Compromise

Thyroglossal duct cysts are typically benign and usually asymptomatic. Malignant transformation is uncommon. Intralaryngeal extension is rare and results in dysphonia or dyspnea. There is no literature nowadays reporting the thyroglossal duct cyst carcinoma combining the clinical features of intralaryngeal extension. The authors present a case of progressive hoarseness and midline neck mass for 2 years. The laryngoscope and computed tomography revealed a 6-cm thyroglossal duct cyst containing ectopic thyroid tissue with intralaryngeal extension and causing airway obstruction. Complete excision with Sistrunk operation revealed papillary thyroid carcinoma. The patient resumed normal phonation after the surgery. There was no evidence of tumor recurrence and no hoarseness or dyspnea at 6 months follow up. This is the first reported case of a huge thyroglossal duct cyst carcinoma with intralaryngeal extension causing airway compromise. Complete excision of tumor is essential and vital to the symptom relief. A thyroglossal duct cyst carcinoma with endolaryngeal involvement should be considered in the differential diagnosis when the case has a massive midline neck mass with ectopic thyroid tissue and develops dyspnea or hoarseness concurrently.

Synchronous carcinoma of thyroglossal duct cyst and native thyroid gland

The unobliterated portion of embryological thyroglossal duct may present as cystic swelling later in life and may contain functional thyroid follicles. This cyst requires excision along with the entire thyroglossal duct remnant and adjacent portion of hyoid bone. At times, the excised specimen could demonstrate a focus of carcinomatous change inside the cyst wall. Very rarely, this thyroglossal duct cyst carcinoma could be associated with malignancy of native thyroid gland. This case report illustrates an interesting case of synchronous carcinoma of thyroglossal duct cyst and native thyroid gland. It also sheds light on the controversies related to the pathophysiology of such association and the dilemmas surrounding the management of thyroglossal duct cyst carcinoma, with or without concurrent carcinoma of thyroid gland.

Thyroglossal duct cyst with hoarseness as the sole symptom and an intralaryngeal extension masquerading as a laryngeal mass: Clinical experience and literature review

A thyroglossal duct cyst is the most common congenital disease in the neck. There are two age groups usually associated with thyroglossal duct cysts: 1-11 years in children and 30-60 years in adults. These midline neck masses are typically located anteriorly in the neck, inferior to the hyoid bone. We report an extremely rare case of an intralaryngeal thyroglossal duct cyst without a neck mass, presenting with hoarseness as the sole symptom. A 64-year-old man presented with a 3-month history of hoarseness. On physical examination, no neck mass or swelling was observed during cervical palpation. Laryngostroboscopy revealed a large submucosal mass in the right glottis and supraglottis, and mobility of the right vocal cord was restricted. Surgery was performed via an external approach to completely resect the cyst, together with the middle part of the hyoid bone. Histopathologic examination of the cyst led to a diagnosis of thyroglossal duct cyst. The patient recovered well and his voice returned to normal. Attention should be paid to the occurrence of rare types of thyroglossal duct cyst in unusual clinical sites. Adequate radiological examinations should be performed, and reading the computed tomography or magnetic resonance imaging scans carefully before surgery is important to avoid misdiagnosis.