title: A Calcitonin-Negative Neuroendocrine Tumor Derived from Follicular Lesions of the Thyroid.
abstract: Neuroendocrine lesions of the thyroid are rare. The most common types are medullary thyroid carcinomas (MTCs) and C-cell hyperplasia. MTCs originate from thyroid parafollicular cells that secrete calcitonin which serves as a serum marker of MTCs. Here, the rare case of a calcitonin-negative neuroendocrine tumor (NET) derived from follicular lesions of the thyroid is described. A 34-year-old man presented at our hospital for the surgical management of an incidental thyroid nodule that was observed on an ultrasound sonography (USG) of the neck. Initially, USG-guided aspiration cytology was performed, and a MTC was suspected. The expressions of thyroglobulin and thyroid transcription factor-1, which are thyroid follicular cell markers, and synaptophysin and chromogranin A, which are neuroendocrine markers, was confirmed following surgical pathology. However, the staining of calcitonin, a marker of MTCs, was not observed. A nonmedullary NET of the thyroid is uncommon, and the distinction between calcitonin-negative NETs and MTCs of the thyroid may be important due to differences in their clinical courses and management.
authors.affiliation: Department of Internal Medicine, Catholic University of Daegu School of Medicine, Daegu, Korea.
authors.forename: Ga Young
authors.initials: GY
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Catholic University of Daegu School of Medicine, Daegu, Korea.
authors.forename: Chul Yun
authors.initials: CY
authors.lastname: Park
authors.affiliation: Department of Pathology, Catholic University of Daegu School of Medicine, Daegu, Korea.
authors.forename: Chang Ho
authors.initials: CH
authors.lastname: Cho
authors.affiliation: Department of Otolaryngology Head and Neck Surgery, Catholic University of Daegu School of Medicine, Daegu, Korea.
authors.forename: June Sik
authors.initials: JS
authors.lastname: Park
authors.affiliation: Department of Internal Medicine, Catholic University of Daegu School of Medicine, Daegu, Korea.
authors.forename: Eui Dal
authors.initials: ED
authors.lastname: Jung
authors.affiliation: Department of Internal Medicine, Catholic University of Daegu School of Medicine, Daegu, Korea. ejjeon@cu.ac.kr.
authors.forename: Eon Ju
authors.initials: EJ
authors.lastname: Jeon
keywords: Calcitonin; Carcinoma, medullary; Neuroendocrine tumors