Histopathological Characterization and Whole Exome Sequencing of Ectopic Thyroid: Fetal Architecture in a Functional Ectopic Gland from Adult Patient

Made available in DSpace on 2018-12-11T17:18:12Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-01-01 Ectopic thyroid results from a migration defect of the developing gland during embryogenesis causing congenital hypothyroidism. But it has also been detected in asymptomatic individuals. This study aimed to investigate the histopathological, functional, and genetic features of human ectopic thyroids. Six samples were histologically examined, and the expression of the specific thyroid proteins was assessed by immunohistochemistry. Two samples were submitted to whole exome sequencing. An oropharynx sample showed immature fetal architecture tissue with clusters or cords of oval thyrocytes and small follicles; one sample exhibited a normal thyroid pattern while four showed colloid goiter. All ectopic thyroids expressed the specific thyroid genes and T4 at similar locations to those observed in normal thyroid. No somatic mutations associated with ectopic thyroid were found. This is the first immature thyroid fetal tissue observed in an ectopic thyroid due to the arrest of structural differentiation early in the colloid stage of development that proved able to synthesize thyroid hormone but not to respond to TSH. Despite the ability of all ectopic thyroids to synthetize specific thyroid proteins and T4, at some point in life, it may be insufficient to support body growth leading to hypothyroidism, as observed in some of the patients. Thyroid Unit Cellular and Molecular Endocrine Laboratory LIM-25 Faculdade de Medicina da Universidade de São Paulo (FMUSP), Avenida Doutor Arnaldo 455, Cerqueira César Adolfo Lutz Institute São Paulo Public Health Service, Av. Dr. Arnaldo 355, Cerqueira César Head and Neck Surgery of Santa Catarina Hospital, Av. Paulista 200, Bela Vista Department of Internal Medicine Botucatu School of Medicine UNESP, Av. Prof. Montenegro, s/n Distrito de Rubião Junior Servicio de Endocrinología Hospital de Pediatría Dr. Juan Garrahan, Combate de los Pozos 1881 Departamento de Cirurgia Na Disciplina de Cirurgia de Cabeça e Pescoço Faculdade de Ciências Médicas UNICAMP, R. Tessália Vieira de Camargo 126 Medicine School Universidade de Fortaleza (Unifor), Av. Washington Soares 1321, Edson Queiroz Postgraduate Program in Biotechnology Universidade Federal de São Paulo (UNIFESP), Pedro de Toledo 669 Thyroid Molecular Sciences Laboratory Universidade Federal de São Paulo Departamento de Ciências Biológicas Postgraduation Programs in Biotechnology and Structural and Functional Biology UNIFESP, Pedro de Toledo 669 Molecular Oncology Center Hospital Sírio-Libanés, Rua Prof. Daher Cutait 69 Department of Internal Medicine Botucatu School of Medicine UNESP, Av. Prof. Montenegro, s/n Distrito de Rubião Junior