Upper neck papillary thyroid cancer (UPTC): A new proposed term for the composite of thyroglossal duct cyst-associated papillary thyroid cancer, pyramidal lobe papillary thyroid cancer, and Delphian node papillary thyroid cancer metastasis

Abstract

Objectives/hypothesis: Thyroglossal duct cyst (TGDC) is a common congenital anomaly, but TGDC carcinoma is rare. Thyroglossal duct cyst carcinoma management is controversial, especially that of the orthotopic thyroid gland. We aim to provide an insight into the pathologic basis of this management controversy through the review of 28 TGDC cancer cases, thus far the largest such series to our knowledge.

Study design: Retrospective.

Methods: Twenty-eight cases recorded as TGDC cancer in the hospital database were reviewed; their initial clinical diagnosis from medical chart review (DX1) and final pathological review diagnosis (DX2) through pathology slides review by our pathologist (blinded to DX1) were compared. The thyroid gland management and pathology were evaluated.

Results: In the 28 TGDC carcinoma (hospital-recorded diagnosis) patients, DX1 and DX2 were respectively reported as 53% and 14% TGDC carcinoma, 11% and 29% as pyramidal lobe primary, and 4% and 25% as metastatic Delphian node. Thirty-two percent of cases were in the indeterminate category, in both DX1 and DX2, but included different patients. Thyroidectomy was performed in 54% of the cases, papillary thyroid cancer (PTC) was reported in 37% of these thyroid glands. Concurrent thyroid gland malignancy was reported in all Delphian node and pyramidal lobe PTC patients.

Conclusion: The diagnosis of TGDC cancer comprises a heterogeneous group that includes true TGDC cancer, pyramidal lobe primary, Delphian node metastasis, and indeterminate cases. We propose a new terminology of upper neck papillary thyroid carcinoma (UPTC) to denote this heterogeneous group and recommend a rational algorithm for management. Correct pathologic subcategory and thyroid ultrasonography are essential for optimal management of thyroid gland in UPTC cases.

Level of evidence: 4. Laryngoscope, 126:1709-1714, 2016.

Keywords: Delphian node metastasis; Thyroglossal duct cyst cancer; midline neck mass; pyramidal lobe PTC.