Diagnosis of papillary carcinoma in a thyroglossal duct cyst by fine-needle aspiration biopsy.

The incidence of papillary thyroid carcinoma arising in a thyroglossal duct cyst is rare and occurs in about 1 % of thyroglossal duct cysts. Only 17 such cases diagnosed with fine-needle aspiration biopsy have been previously reported in the English-language literature, with a diagnostic rate of 53%. In this article, the cytologic features of the current case are emphasized and those of the previous reported cases are briefly reviewed. Diagnostic pitfalls of papillary carcinoma arising in thyroglossal duct cysts diagnosed by fine-needle aspiration biopsy are also discussed.