Synchronous malignancies of thyroglossal duct cyst and thyroid gland.

Malignant involvement of thyroglossal duct cyst is rare, still rarer is the synchronous malignant involvement of the thyroid gland. Although the Sistrunk procedure is often regarded as adequate, controversy exists of the need for an additional total thyroidectomy and radioiodine ablative therapy, the decision of which depends upon the presence of (i) suspicious thyroid gland nodule; (ii) presence of lymphadenopathy; or (iii) a previous history of neck irradiation. We report a 47-year-old woman diagnosed with papillary carcinoma within a recurrent thyroglossal duct cyst with infiltration into surrounding soft tissues and a suspicious thyroid nodule of the left thyroid lobe with no regional lymph node involvement. On final histopathology, the left thyroid nodule had a follicular variant of papillary carcinoma thyroid without regional nodal involvement. The patient underwent total thyroidectomy with radioactive iodine postoperatively.