title: Pediatric medullary carcinoma of the thyroid with point mutation of RET proto-oncogene associated with multiple endocrine neoplasia and initially diagnosed by fine-needle aspiration biopsy.
abstract: A 7-year-old girl presented with a thyroid mass, elevated serum levels of calcitonin and carcinoembryonic antigen, as well as multiple mucosal nodules in the upper lip and tongue. Cytologic material obtained by fine-needle aspiration biopsy from the thyroid mass was diagnosed as medullary carcinoma and confirmed by immunohistochemical studies in the cell-block sections. Subsequent histopathologic examination showed involvement of both thyroid lobes by medullary carcinoma, and electron microscopic studies further confirmed the diagnosis. Molecular studies showed a point mutation in amino acid 918 in exon 16 of the RET proto-oncogene. Biopsies from the upper lip and tongue showed mucosal neuromas. Fine-needle aspiration biopsy is frequently used in the initial evaluation of thyroid nodules. This case illustrates the value of fine-needle aspiration biopsy as a safe and accurate diagnostic modality in the workup of pediatric thyroid nodules. Fine-needle aspiration biopsy should always be considered for the investigation of thyroid nodules in pediatric patients.
authors.affiliation: Department of Pathology, University of Mississippi Medical Center, Jackson, MS, USA.
authors.forename: Chiling
authors.initials: C
authors.lastname: Chai
authors.forename: Luciano B
authors.initials: LB
authors.lastname: Lemos
authors.forename: Margot
authors.initials: M
authors.lastname: Kaelbling
authors.forename: Mithra
authors.initials: M
authors.lastname: Baliga
mesh_terms: D001707:Biopsy, Needle; D018276:Carcinoma, Medullary / Q000235:genetics / Q000473:pathology*; D002648:Child; D029721:Drosophila Proteins; D005260:Female; D006801:Humans; D018814:Multiple Endocrine Neoplasia Type 2b / Q000235:genetics / Q000473:pathology*; D017354:Point Mutation; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics*; D013964:Thyroid Neoplasms / Q000235:genetics / Q000473:pathology*
chemical_list: D029721:Drosophila Proteins; C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases; C416649:Ret protein, Drosophila