Primary papillary carcinoma in a thyroglossal cyst--a case report.

A benign thyroglossal cyst is a common clinical condition and is second only to a cervical lymph node as the most common cause of a solitary neck swelling. Primary carcinoma of a thyroglossal cyst, however, is rare and has been described in only 115 cases in the literature. The malignant cysts are clinically difficult to differentiate from benign lesions and the diagnosis often rests on histopathological examination. Before initiating treatment, primary papillary carcinoma of the thyroid gland must be excluded. The treatment options range from simple excision to a Sistrunk operation with concurrent cervical lymph node dissection. We describe here a case of papillary carcinoma of a thyroglossal cyst and review the 115 reported cases.