Papillary Carcinoma Arising in Thyroglossal Duct Cyst: A Retrospective Analysis (Cancer of the Thyroid or Primary Cancer of the Thyroglossal Cyst)

摘要

Thyroglossal duct cysts are one of the most common congenital abnormalities of the cervical region. Complications of these swellings are rare, and among these, appearance of a carcinoma has also been noted. Thyroglossal duct cyst carcinoma (TGDC) is a rare entity and its management is controversial. The incidence of thyroid papillary carcinoma in thyroglossal duct cyst is less than 1%, in most cases, the diagnosis is made postoperatively. We report the case of an adult female patient with a papillary carcinoma arising in a thyroglossal duct cyst. Our aim is defining a clinical protocol to diagnose the thyreoglossal du ct carcinoma through clinical features, radiological investigations, cytological and histopathological examinations and, through this diagnostic protocol, to choose the best surgical approach. The literature contains 300 cases of this pathology; papillary histotype constitutes about 80%, then squamocellular carcinoma, mixed folliculo-papillary carcinoma and adenocarcinoma follow. The literature suggests two different hypotheses: neoplasia originating from ectopic thyroid tissue and plurifocal theory. The adopted diagnostic investigations are: ultrasonography, Fine Needle Aspiration Biopsy (FNAB), Magnetic Resonance Imaging (MRI). Our patient was treated using a modified Sistrunk’s procedure operation, in which thyroidectomy proved crucial for the correct diagnosis and continuation of appropriate treatment. Our case confirms the difficulty in distinguishing a primitive thyroglossal duct carcinoma from a synchronous metastatic papillary carcinoma of the thyroid. This dilemma often remains unresolved. The two different surgical approaches reported in the literature, one more conservative and the other more aggressive, apparently alternatives are instead complementary and adequate when strict diagnostic criteria and adequate follow-up, are observed. The first year follow-up includes the thyroglobulin level determination and a neck ecografic scan every 3 months. The patient has been following for two years without any metastasis.