Squamous cell carcinoma arising from a thyroglossal duct cyst: A case report and review of the literature

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.

Clinical and cytopathological features of suspected thyroglossal duct cysts and neoplasms arising from them: A large series from a referral cancer center

BACKGROUND

Thyroglossal duct cysts (TGDCs) are the most common congenital midline cystic lesions in the neck, and they are often evaluated by fine-needle aspiration. Recognizing the cytomorphologic features of TGDCs and their mimics is important for clinical management.

METHODS

This study examined the clinical, radiological, and cytopathological features of 86 ultrasonography-guided fine-needle aspiration (US-FNA) specimens from clinically suspected TGDCs or malignancies arising from TGDCs and correlated the findings with surgical follow-up and/or imaging studies.

RESULTS

According to ultrasound examinations of 66 lesions, 17 (25.8%) were cystic, 8 (12.1%) were cystic with septations, 21 (31.8%) were cystic with solid nodules, and 20 (30.3%) were solid or cystic with internal debris. Cytopathologically, 81 lesions (94%) were categorized as benign, 2 (2%) were categorized as atypical, and 3 (3%) were categorized as malignant. In benign lesions, proteinaceous material (63%), histiocytes (63%), colloid (37%), squamous cells (35%), columnar cells (32%), follicular cells (15%), inflammatory cells (9%), and multinucleated giant cells (9%) were noted. Diagnoses in the benign category included TGDC in 64 patients (75%), TGDC or mimics (colloid nodule/epidermoid cyst) in 14 patients (17%), a colloid nodule in 1 patient, and thyroiditis in 1 patient. Surgical resection, performed in 23 patients, confirmed TGDCs in 12, benign mimics in 7, and carcinoma in 4.

CONCLUSIONS

Cytopathological features, in conjunction with imaging, allowed a definite diagnosis of TGDC in most patients (75%). The presence of mature squamous cells, thyroid follicular cells, with or without colloid and/or lymphocytes alone allowed a differential diagnosis of TGDC and its mimics in 17%. US-FNA findings could not distinguish primary carcinomas arising from TGDCs from metastatic tumors.

Synchronous squamous cell carcinoma and papillary thyroid carcinoma arising from the thyroglossal duct remnant: Case report and a review of the literature

Squamous cell carcinoma and papillary thyroid carcinoma simultaneously spreading from the thyroglossal duct remnant (TGDR) is a very rare event. The recognition of this condition allows a correct management and treatment, offering the best chances of cure to the patient. We describe the case of a 42-year-old woman who noticed a right-sided lump in her neck. An ultrasound scan confirmed multiple clusters of enlarged lymph nodes on the right side associated to a pre-hyoidal solid nodule. The thyroid gland was normal. Fine-needle aspiration cytology on two nodes revealed distinct metastases from squamous cell carcinoma and from papillary thyroid carcinoma. A careful screening for other head and neck tumors was negative. She underwent a Sistrunk procedure, total thyroidectomy and right lateral lymphadenectomy with en bloc jugular vein resection. On histology, a 2 cm papillary and a small squamous cell carcinoma of the TGDR were documented, with nodal metastases from both primaries. We report the overall management strategy, treatment and outcome at 26-month follow-up, and a review of the literature.

Squamous Cell Carcinoma of a Thyroglossal Duct Cyst and the Role of a Level IA Neck Dissection

Squamous cell carcinoma of a thyroglossal duct cyst is exceedingly rare, with less than 30 cases reported across the literature. Herein, we present a case of squamous cell carcinoma (SCC) of a thyroglossal duct cyst (TGDC) and discuss the utility of a level IA neck dissection in these cases. In 2018, a 62-year-old female presented to a university-affiliated otolaryngologist with symptoms of dysphagia and a palpable anterior midline neck mass. MRI demonstrated a 3.1 × 2.0-cm mass concerning an invasive TGDC. She was referred to our institution for further management. Preoperative imaging demonstrated an invasive TGDC but no pathological nodes. A Sistrunk procedure and a IA neck dissection were performed. Pathology demonstrated one pathological node in the neck dissection specimen. In summary, a bilateral IA neck dissection was performed on a clinically node zero (N0) patient, and a pathological node was ultimately identified. We hope that by introducing this idea of a IA neck dissection for SCC of a TGDC, we can prompt further investigation into the utility of this procedure for these uniquely rare cases.