Objective: To describe a case of thyroglossal duct cyst carcinoma that arose in a patient with right thyroid lobe hemiagenesis.
Methods: We present the imaging, physical examination findings, treatment, and clinical course of the study patient.
Results: A 35-year-old woman was evaluated for a neck mass that had been present for 6 months and was slowly growing. She reported a previous diagnosis of right hemithyroid agenesis. The patient's preoperative workup included ultrasonography of the neck and head and neck T1- and T2-weighted magnetic resonance imaging, which showed right hemithyroid agenesis and a cystic lesion in the median region of the neck below the hyoid bone. Findings from chest x-rays and thyroid function tests were normal. The patient underwent a modified Sistrunk procedure that included removal of the median portion of the hyoid bone. Histologic findings showed a 2.5-cm thyroglossal duct cyst with a 0.6-cm focus of follicular variant of papillary carcinoma with invasion of the cyst wall. Total thyroidectomy was not performed because of the absence of tumoral invasion of the parenchyma around the thyroglossal duct cyst and because the patient was at low risk for aggressive disease. Cervical ultrasonography examinations were performed 6, 12, and 24 months after treatment, and all findings were normal. Presently, the patient is symptom-free after 4 years of follow-up and has no evidence of disease.
Conclusion: Incidentally discovered, well-differentiated thyroid cancer that is confined to a thyroglossal duct cyst in a patient at low risk for aggressive disease can be adequately treated by a modified Sistrunk procedure that includes the median portion of the hyoid bone.