title: Thyroid carcinomas involving follicular and parafollicular C cells: seventeen cases with characterization of RET oncogenic activation.
abstract: Recent studies have focused on the occurrence of concomitant medullary-papillary thyroid carcinomas (MTC-PTC). The aims of this report were to compare the frequency of occult PTC in a population with MTC versus a control population that had undergone thyroidectomies and to check whether differences could be related to particular phenotype or genotype. To achieve these goals, we determined the frequency of occult PTC among patients operated for MTC (n = 82) or undergoing total thyroidectomy mainly for goiter and/or nodules (n = 7313) between 1994-2001. We then examined the clinical, histologic, and genetic characteristics (using a bio-chemical family inquiry and screening for RET germline mutations) of patients with associated PTC-MTC. Results show a significantly higher frequency of occult PTC in MTC (14.7%) than in total thyroidectomy (6.8%; p < 0.01). Seventeen cases of MTC or bilateral C-cell hyperplasia (CCH) and separate occult PTC were identified from 16 different families. Although common RET mutations providing evidence of familial forms of MTC were identified in only 3 of 16 families, clinical and histologic features usually seen in inherited forms of MTC such as young age of occurrence, bilateral CCH or associated case in family were found in 11 of the remaining 14 patients. In conclusion, results suggest that the association of MTC-PTC is not only a coincidence. Surprisingly, 11 of 17 MTC-PTC patients exhibited clinical, histologic, and/or family features usually encountered in familial forms despite the fact that no RET defect were present. This suggests the possible involvement of another gene or uncommon abnormality of RET gene.
authors.affiliation: Department of Endocrinology and Metabolism, University Hospital, Lille, France. mc-vantyghem@chru-lille.fr
authors.forename: M-C
authors.initials: MC
authors.lastname: Vantyghem
authors.forename: P
authors.initials: P
authors.lastname: Pigny
authors.forename: E
authors.initials: E
authors.lastname: Leteurtre
authors.forename: L
authors.initials: L
authors.lastname: Leclerc
authors.forename: C
authors.initials: C
authors.lastname: Bauters
authors.forename: C
authors.initials: C
authors.lastname: Douillard
authors.forename: M
authors.initials: M
authors.lastname: D'Herbomez
authors.forename: B
authors.initials: B
authors.lastname: Carnaille
authors.forename: C
authors.initials: C
authors.lastname: Proye
authors.forename: J-L
authors.initials: JL
authors.lastname: Wemeau
authors.forename: M
authors.initials: M
authors.lastname: Lecomte-Houcke
mesh_terms: D000328:Adult; D000368:Aged; D018276:Carcinoma, Medullary / Q000235:genetics* / Q000473:pathology; D002291:Carcinoma, Papillary / Q000235:genetics* / Q000473:pathology; D006801:Humans; D006965:Hyperplasia; D008875:Middle Aged; D009154:Mutation; D015513:Oncogene Proteins / Q000235:genetics*; D011230:Precancerous Conditions / Q000235:genetics* / Q000473:pathology; D051096:Proto-Oncogene Proteins c-ret; D011519:Proto-Oncogenes; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics*; D013964:Thyroid Neoplasms / Q000235:genetics* / Q000473:pathology
chemical_list: D015513:Oncogene Proteins; D051096:Proto-Oncogene Proteins c-ret; C099282:RET protein, human; D020794:Receptor Protein-Tyrosine Kinases