Papillary Thyroid Carcinoma Identified after Sistrunk Procedure: Report of Two Cases and Review of the Literature

Abstract

Thyroglossal duct cysts represent the most common congenital cervical malformations. Carcinomas arising in the thyroglossal duct cysts are rare neoplasms characterized by a relatively non aggressive behavior with rare lymph node spread. Approximately 1% of thyroglossal cysts contain a carcinoma. The most frequent histological type is papillary carcinoma, accounting for about 80% of cases. Currently, most authors agree about their primary origin ex novo from ectopic thyroid tissue in the cyst. In most cases the diagnosis of thyroglossal duct carcinoma (TDC) is not made until histopathological examination has been performed on a resected cyst without any suspected clinical sign of malignancy. The definition of the correct surgical treatment for these carcinomas is still controversial; most authors maintain that resection of a TDC with the Sistrunk procedure can be considered oncologically adequate when dealing with a differentiated carcinoma without extracapsular invasion and/or lymph node metastases and with a normal thyroid. We present two cases of papillary thyroid carcinoma identified after resection of a thyroglossal cyst according to the Sistrunk procedure and managed with different surgical approaches according to the different sites of the tumors. In addition, we discuss appropriate therapeutic strategies in light of the most recent data in the literature.

Cysts of the Neck, Unknown Primary Tumor, and Neck Dissection

“…Eighty percent of such neoplasms are papillary thyroid carcinomas; the remaining neoplasms are predominantly follicular carcinomas or squamous carcinomas. [52][53][54][55] Criteria for diagnosis include demonstration, preferably by microscopic examination, of a thyroglossal remnant and a normal thyroid gland. Because of the paucity of cases and the fact that the malignancy is not recognized until after complete pathologic examination of the remnant, it is difficult to delineate treatment and prognosis.…”

“…Most researchers agree, however, that (1) total thyroidectomy is not routinely indicated as long as there are no palpable abnormalities in the gland and no significant scintiscan findings and (2) the Sistrunk operation probably offers a reasonable chance of cure. [52][53][54][55] Cervical Thymic Cyst Cervical thymic cysts are morphologically identical to their mediastinal counterparts. 56 They are found in the anterior triangle of the neck along the normal path of descent of the thymus, with or without parathyroid glands, and they may have a fibrous band or a solid thymic cord connection to the pharynx or mediastinum.…”

Does Papillary Carcinoma of Thyroglossal Duct Cyst Develop De Novo?

“…A controversial issue is whether papillary carcinoma in the TDC develops de novo or as a type of metastasis from an occult tumor nidus in the thyroid gland [ 9 , 10 , 12 – 14 ]. A limited number of reported cases describe the presentation of a TDC papillary carcinoma accompanied by a thyroid gland papillary carcinoma [ 6 – 8 , 15 – 17 ]. It may be difficult to differentiate primary papillary carcinoma of the TDC from metastasis of an occult carcinoma of the thyroid gland.…”

“…Due to embryological remnants of thyroid tissue located in the TDC, the same malignant tumors that develop in the thyroid gland can also develop in the TDC. Papillary type thyroid carcinoma can develop in the TDC de novo with an incidence of 1%, although some authors believe that the thyroglossal duct instead serves as a natural route for occult thyroid carcinoma metastases [ 6 – 8 ]. Thyroid carcinomas originating from the TDC are mostly seen in females between the ages of 20–60 years and present as a complaint of pain at the level of the thyrohyoid membrane along the neck midline with a physical examination finding of a palpable mass without tenderness [ 9 ].…”

Thyroglossal duct cyst carcinoma with concurrent thyroid carcinoma: a case report

“…Although some authors consider the thyroglossal duct as a natural way of spread of an occult thyroid cancer and also recommend total thyroidectomy with neck dissection, others believe that the malignancy arises directly in the thyroglossal duct cyst and consider surgical excision of the cyst as curative, at least in some cases [ 4 , 14 , 15 ]. The distinction between primary carcinoma arising from ectopic thyroid tissue and metastatic disease from an occult or manifest thyroid gland carcinoma is very important in therapeutic decision-making, but it is often difficult to achieve.…”