Can Medullary Thyroid Carcinoma Arise in Thyroglossal Duct Cysts? A Search for Parafollicular C-cells in 41 Resected Cases

Abstract

Thyroglossal duct cysts (TGDCs) are present in ~7% of adults and develop from the midline migratory tract between the foramen cecum and anatomic location of the thyroid. Thyroid tissue can be identified in 2/3 of TGDCs, and up to 1% develop associated malignancy, 90% of which are papillary thyroid carcinoma. Cases of follicular and anaplastic carcinoma have been documented, but there are no reports of medullary thyroid carcinoma arising in a TGDC. This is presumably due to the distinct embryologic origin of parafollicular C-cells, from which medullary carcinoma arises. The goal of this study is to determine whether parafollicular C-cells are present in TGDCs. H&E sections from 41 TGDC cases were examined for thyroid tissue, thyroglossal duct remnants, ultimobranchial remnants, and parafollicular C-cells. Immunohistochemistry was performed for TTF-1 and calcitonin. Eighty three percent (34/41) of cases contained thyroid tissue on H&E and by TTF-1. No cases (0/41) had ultimobranchial remnants or parafollicular C-cells on H&E or with calcitonin. One case of papillary carcinoma in a TGDC was identified. These cases illustrate that although TGDCs often contain thyroid tissue, parafollicular C-cells are absent. Therefore, unlike other thyroid neoplasms, there is no evidence to support the possibility of medullary carcinoma arising in a TGDC.

Thyroglossal duct cyst papillary carcinoma with lymphatic infiltration: A case report

“…It may develop from metastatic thyroid cancer or may originate de novo from ectopic thyroid tissue within the cyst. Several papers reporting entrapped thyroid follicles in the cyst wall, persistent absence of medullary cells, and consistent lack of medullary carcinoma in TDC cases strongly support the “de novo theory” 5–7 …”

“…Several papers reporting entrapped thyroid follicles in the cyst wall, persistent absence of medullary cells, and consistent lack of medullary carcinoma in TDC cases strongly support the "de novo theory". [5][6][7] TDCC has been reported on ultrasound, contrast-enhanced neck computed tomography, and magnetic resonance imaging. On ultrasound, TDCC can present as a lesion with a cystic and solid component, intra-cystic septation, and an echogenic mural mass with intralesional punctate calcification.…”

Clinical Characteristics and Prognosis of Infants and Children <3 Years of Age With Thyroglossal Duct Cyst Complicated With a Parapharyngeal Mass: A Case Series Study

“…3 In adults, TGDC has the potential to develop associated malignancy. 4 It is associated with a mortality rate of 30% to 40% in neonates due to preterm delivery or sudden infant death. 5 Studies reporting the surgical treatment of TGDCs complicated with a parapharyngeal mass in infants and young children are scarce.…”