Clear-cell follicular adenoma of ectopic thyroid in the submandibular region

A case of clear-cell follicular adenoma arising in ectopic thyroid tissue i s reported. The 2.0-cm tumor arose in the submandibular region in a 29-yr-o ld female. The diagnosis was established on the basis of light microscopic morphology, a positive thyroglobulin immunohistology, and the presence of n ormal thyroid tissue surrounding the mass. Preoperative computed tomography (CT) scan and postoperative ultrasound studies revealed a normal orthotopi c thyroid gland. No additional tumors have since been detected. The patient is free of recurrent or metastatic disease 54 mo following excision of the mass. Only eight previously published reports have described ectopic thyro id tissue in the submandibular region, all but one of which lacked an ortho topic thyroid gland. In this article, we describe the pathological features of our case and review the existing literature on the subject.