title: Benign teratoma of the thyroid gland.
abstract: Although pathology reports of thyroid tissue in ovarian teratomas are abundant, benign teratomas of the thyroid are extremely rare in adolescents and adults. Therefore, their clinical characteristics are still not well characterized. We report a case of a 54-year-old woman with a growing mass in her neck. Left lobectomy of the thyroid revealed it to be a benign thyroid teratoma composed of tissues from all three germ layers. Preoperative evaluations included thyroid ultrasonography (US), ultrasound-guided fine needle aspiration cytology (FNAC), and computed tomography (CT) of the neck. A 4.7-cm, well defined, predominantly hypoechoic mass intermingled with hyperechoic internal lesions, was observed in the inferior portion of the left thyroid lobe with substernal extension on US. The posterior extent of the nodule was not visualized due to deep attenuation of the echo. US-guided FNAC failed to reveal any thyroid follicular cells, but suggested a benign cystic tumor. Neck CT hinted at the diagnosis of teratoma because the mass contained large amounts of fat, and the margin was well defined. Extrathyroidal extension and cervical lymphadenopathy were not seen. She underwent left thyroid lobectomy, and histologic examination confirmed benign thyroid teratoma. To the best of our knowledge, this is the first case report of benign thyroid teratoma in Korea.
authors.affiliation: Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Chan Young
authors.initials: CY
authors.lastname: Oak
authors.affiliation: Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Hee Kyung
authors.initials: HK
authors.lastname: Kim
authors.affiliation: Department of Otolaryngology, Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Tae Mi
authors.initials: TM
authors.lastname: Yoon
authors.affiliation: Department of Otolaryngology, Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Sang Chul
authors.initials: SC
authors.lastname: Lim
authors.affiliation: Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Hyun Bum
authors.initials: HB
authors.lastname: Park
authors.affiliation: Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Hyung Chul
authors.initials: HC
authors.lastname: Park
authors.affiliation: Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Min Gui
authors.initials: MG
authors.lastname: Han
authors.affiliation: Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Ho-Cheol
authors.initials: HC
authors.lastname: Kang
keywords: Teratoma; Thyroid; Ultrasonography