Upper neck papillary thyroid carcinoma: a case report

Upper neck papillary thyroid carcinoma (UPTC) encompasses thyroglossal duct cyst carcinoma (TGDCC), pyramidal lobe papillary thyroid carcinoma (PTC), and Delphian node metastasis. TGDCC, a rare malignancy, occurs in less than 1% of TGDCs, with papillary carcinoma being the predominant subtype. Accurate diagnosis and management of TGDCC are challenging due to its overlapping features with other UPTC subtypes.

A 30-year-old South Asian male presented with a painless midline neck swelling for 1 year and a right submandibular swelling for 3 months. Ultrasound and contrast-enhanced CT revealed a midline cystic lesion with calcifications, consistent with a TGDC, and a benign submandibular cyst. The patient underwent a Sistrunk procedure along with the submandibular cyst excision and Level 1B neck dissection.

TGDCC typically presents as a painless midline neck swelling, with over 90% of cases being papillary carcinoma. Ultrasound is the initial imaging modality, and fine-needle aspiration has limited diagnostic accuracy. The Sistrunk procedure is the standard treatment for TGDCC, but the high incidence of concurrent thyroid malignancy (20%-62%) prompts debate over routine thyroidectomy. For low-risk TGDCC patients (under 45, no lymph node involvement, negative margins), the Sistrunk procedure alone may suffice, with annual surveillance recommended if thyroidectomy is not performed.

This case underscores the utility of the UPTC classification in distinguishing TGDCC from other subtypes, guiding precise surgical intervention. The Sistrunk procedure effectively managed low-risk TGDCC, with ongoing surveillance essential to monitor for recurrence or thyroid malignancy.