Papillary carcinoma in a thyroglossal duct cyst: management and algorithm for treatment of a rare entity

Papillary thyroid carcinoma from a thyroglossal cyst: case series

Papillary carcinoma originating from a thyroglossal cyst represents an infrequent finding, which occurs in ~1% of cases of thyroglossal cyst and its presentation is usually the same as that of a benign cyst, which represents the most frequent benign congenital lesion of the neck. The diagnosis is usually presented as a finding on the histopathological examination. Two cases of a thyroglossal cyst with later development of malignancy are presented. The first, a 30-year-old female, and the second, a 32-year-old male. Both began their condition after presenting an increase in volume in the neck, the female presented a right sub-mental triangle of 1 year of evolution, and the male on the anterior side of the neck. In both cases, the diagnosis of thyroglossal cyst was made by the physical examination and findings of cervical ultrasound and computed axial tomography. Surgical management consisted of the Sistrunk procedure with a definitive histopathological result for papillary thyroid carcinoma originating from thyroglossal cyst. In the case of the male patient, the Sistrunk procedure was performed along a total thyroidectomy, although in the female patient, a total thyroidectomy was performed in a second stage. Patients were then discharged and referred to the endocrinology service for further medical treatment. The management of these cases continues to be controversial due to the limited number of reported cases, so the multidisciplinary management and individualization of each case plays a fundamental role in the management of this rare condition.

Thyroglossal duct cyst cancer most likely arises from a thyroid gland remnant

Thyroglossal duct cancer is a rare entity, occurring in 1.5 % of all thyroglossal duct cysts (TDC). A definitive consensus about its neoplastic origin has not been established as two contrasting theories exist, one proposing an origin in extra-thyroid remnants and the other a metastatic localization of a primary thyroid cancer. We compare morphological and molecular characteristics of both thyroglossal and thyroid carcinomas in a case series from our institute. We evaluated histology of 80 TDC. In 12 cases, prior cytological evaluation had been performed by liquid-based cytology (LBC). The BRAF gene was examined for mutations, and the histology of both thyroglossal duct and synchronous thyroid carcinoma was reevaluated. In 9 out of 80 (11 %) TDC cases, a papillary thyroid cancer (PTC) was diagnosed. In five out of nine (56 %) thyroglossal carcinomas, a synchronous thyroid cancer was diagnosed: 3 PTC and 2 follicular variant PTC (FVPC). In five thyroglossal carcinomas, mutated BRAF (V600E) was found, three in PTC and in thyroglossal as well as in the synchronous tumor in the thyroid. All the patients are in a disease-free status and still alive. Our results suggest that the majority of thyroglossal carcinomas most likely develop as a primary malignancy from a thyroid remnant. Neither the presence of V600E BRAF mutations nor that of a well-differentiated thyroid carcinoma changed the outcome or disease-free survival. We suggest that a diagnosis of thyroglossal carcinoma should be followed by a detailed evaluation of the thyroid gland. In the absence of clinical and radiological thyroid alterations, follow-up as for thyroid cancer is the correct management.