Biomedical subjects
Serge Guyétant
Publications and source records attributed to Serge Guyétant.
[Thyroid metastases of an adrenocortical carcinoma 41 years after the diagnosis of the primary tumor].
Thyroid metastasis are rare and represent less than 4% of malignant thyroid tumors in clinical series. They can develop many years after diagnosis of the primary tumor. We report a case of thyroid metastasis of adrenocortical carcinoma, 41 years after the diagnosis of the primary tumor. Such a long latent interval is exceptional. To our knowledge, this is the first case published. Based on current literature, we offer a brief review on thyroid metastasis and differential diagnosis of thyroid gland clear cell neoplasm.
Decreased expression of thyrotropin receptor gene suggests a high-risk subgroup for oncocytic adenoma.
OBJECTIVE: The malignancy of thyroid oncocytic tumours, or oncocytomas, is higher than that of follicular tumours. The aim of this study was to investigate the role of thyroid-specific genes in oncocytic tumours and papillary carcinomas. DESIGN AND METHODS: We compared 29 oncocytic tumours with 12 papillary carcinomas. Real-time quantitative PCR was used to measure the expression of thyroid-specific differentiation markers (thyrotrophin-stimulation hormone receptor (TSHR), thyroglobulin (TG) and Na(+)/I(-) symporter (NIS)), transcription factors (thyroid transcription factor-1 (TTF-1) and paired box gene-8 (PAX8)) and nuclear receptors (peroxisome proliferator-activated receptor (PPARgamma1) and thyroid hormone receptor (TRbeta1)) involved in thyroid carcinogenesis. RESULTS: TSHR, TTF-1 and TRbeta1 levels were significantly lower in oncocytic tumours than in papillary carcinomas, as a result of specific biological changes in oncocytic tumours. However, PAX8 and PPARgamma1 did not seem to be involved in the process. Applying the criterion of the underexpression of the thyroid-specific differentiation markers, TSHR, TG and NIS, we classified the oncocytic tumours and papillary carcinomas into three groups. In the first, all three markers were underexpressed; in the second, TSHR was normal while TG and NIS were underexpressed; and in the third, only NIS was underexpressed. The expression patterns revealed that 13 of the 24 oncocytic adenomas underexpressing TSHR in our study, as did four of the five oncocytic carcinomas. CONCLUSION: Cases of oncocytic adenoma associated with low levels of TSHR could be putative oncocytic carcinomas and should therefore receive adequate follow-up [corrected].
C-cell hyperplasia and medullary thyroid carcinoma: clinicopathological and genetic correlations in 66 consecutive patients.
Routine calcitonin (CT) assay programs and genetic testing for RET proto-oncogene mutations have consistently modified the management and understanding of C-cell proliferative disorders. We report a series of 66 consecutive patients with C-cell hyperplasia (CCH) or medullary thyroid carcinoma (MTC) observed in our institution within an 8-year time period. All the patients had a preoperative basal CT assay and an RET proto-oncogene sequencing. Seventeen patients (F-M ratio: 8:9, mean age: 29.7 y) had a multiple endocrine neoplasia Type 2: 3 children <10 years of age had CCH only, and 14 patients had an MTC, with neoplastic CCH in 10/14 cases. Twenty-seven patients (F-M ratio: 18:9, mean age: 56.6 y) had a sporadic MTC, with physiological CCH in 8 and neoplastic CCH in 3 cases. Twenty-two men (mean age: 46.2 y) had CCH only (physiological CCH in 17 men and neoplastic CCH in 5). We conclude that (1) clinical and pathological characteristics (familial MTC, tumor multifocality, neoplastic CCH) usually associated with hereditary MTC may be misleading and that on the contrary, RET sequencing gives no false positive result; (2) sporadic neoplastic CCH accompanies (and probably precedes) a number of sporadic MTC; and (3) women presenting with a sporadic elevated basal CT have a 100% risk of having an MTC (15/15), but this risk is 3-fold less in men (31%), who will most often have CCH only (69%).
[Diagnosis of the follicular variant of papillary thyroid carcinoma. Significance of immunohistochemistry].
AIMS: To study the expression of cytokeratin 19 (CK-19), HBME-1 and Ret in follicular-patterned thyroid tumors, and their significance for the diagnosis of the follicular variant of papillary thyroid carcinoma. MATERIALS AND METHODS: 111 well-differentiated follicular tumors were examined by immunohistochemistry: 59 papillary carcinomas (43 of the follicular variant), 40 follicular adenomas (among which 11 atypical adenomas), 10 oxyphil cell tumors and 2 follicular carcinomas. RESULTS: CK-19 was diffusely expressed in all the papillary carcinomas, and was also expressed in 2/4 oxyphil cell carcinomas and 4/11 atypical adenomas. 90% of the follicular adenomas (26/29), the six oxyphil cell adenomas and the two follicular carcinomas showed at best a focal staining of dystrophic areas. 78% of the papillary carcinomas and 3/11 atypical adenomas were stained with HBME-1, whereas 26/29 adenomas (90%) and the 10 oxyphil cell tumors were negative. 34% of the papillary carcinomas expressed Ret (most of them were of the usual type (14/20)). The staining was often weak and focal (13/20). The other tumors were all negative for Ret. CONCLUSIONS: CK-19 is a sensitive (100%) and specific (82.5%) marker of papillary carcinomas, which can be helpful in the diagnosis of its follicular variant. HBME-1 can improve this specificity when associated with CK-19. The Ret protein expression is of limited practical interest.
[Definition and histologic characterization of neuroendocrine tumors].
Neuroendocrine tumours are defined by a common phenotype, which is not supported by a common embryologic origin. This common phenotype is characterized by the expression of general neuroendocrine markers, and sometimes by cell specific hormonal products. Neuroendocrine tumours are ubiquitous, but the major localizations are the digestive tract. According to the classification of lung tumours, they are divided in low grade and high grade tumours. Since most digestive and pancreatic tumours are low grade tumours, a specific classification of neuroendocrine tumours was recently proposed. Size, degree of invasion, major secretion, and proliferation rate are the main criteria of this classification. Most neuroendocrine tumours are sporadic. A few cases occur in the context of a multiple endocrine neoplasia type 1.