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S Guyetant

Publications and source records attributed to S Guyetant.

16 recordsLinked to original sources
PubMed2001

Defective mitochondrial ATP synthesis in oxyphilic thyroid tumors.

Oxyphilic tumors (oncocytomas or Hürthle cell tumors) form a rare subgroup of thyroid tumors characterized by cells containing abundant mitochondria. The relationship between the mitochondrial proliferation and the pathogenesis of these tumors is unknown. We have assessed the expression of the mitochondrial ND2 and ND5 (subunits of the nicotinamide adenine dinucleotide dehydrogenase complex) genes and the nuclear UCP2 (uncoupling protein 2) gene in 22 oxyphilic thyroid tumors and matched controls. The consumption of oxygen in mitochondria from tumors was determined by polarography. ATP assays were used to explore the mitochondrial respiratory chain activity and the oxidative phosphorylation coupling in seven fresh thyroid tumors and controls. Adenosine triphosphate synthesis was significantly lower in all the tumors, compared with controls, suggesting that a coupling defect in oxidative phosphorylation may be a cause of mitochondrial hyperplasia in oxyphilic thyroid tumors.

Adenoma, Oxyphilic↗
PubMed2000

[Diagnosis of parathyroid cysts: value of parathyroid hormone level in puncture fluid].

OBJECTIVE: Determine a means of establishing the diagnosis of parathyroid cysts preoperatively. PATIENTS AND METHODS: Classically, crystal-clear watery fluid removed by fine-needle aspiration of a suspected thyroid mass raises the suspicion of a parathyroid cyst. Immunoradiometric assay of parathyroid hormone level in the fluid may give the diagnosis sparing unnecessary surgery. RESULTS: Over the last 5 years, among the 12 patients presenting a suspected thyroid cyst containing a crystal-clear fluid, we were able to diagnose 3 cases of parathyroid cysts due to the considerable elevation of parathyroid hormone in the puncture fluid. None of these patients had hyperparathyroidism. In patients with a thyroid cyst, parathyroid hormone level in the puncture fluid was nil. CONCLUSION: The parathyroid nature of cervical cysts containing crystal-clear fluid can be established by assaying parathyroid hormone in the puncture fluid. Non-functional parathyroid cysts may be treated by repeated aspiration. Serum calcium level must be checked regularly to detect potential hyperparathryoidism.

Adult↗
PubMed2000

No evidence of thyrotropin receptor and G(s alpha) gene mutation in high iodine uptake thyroid carcinoma.

Usually, thyroid carcinoma presents as a cold nodule on radioiodine scintigraphy. High-uptake nodules on iodine thyroid scans are associated with an exceedingly low incidence of malignancy. Only 29 cases of carcinomas appearing as hot or warm nodules have as yet been reported. From 1993 to 1999, we have observed eight similar cases (4 hot and 4 warm thyroid nodules) suggesting that thyroid carcinomas may not be as rare as usually considered in these circumstances. Four tumors were available for molecular analysis on paraffin-embedded sections. Because no mutations were found in the whole coding portions of thyrotropin-receptor (TSH-R) gene and fragments encompassing the mutational hot spots of the G(s alpha) gene, it is unlikely that activating mutations of the TSH-R or G(s alpha) genes were involved in these carcinomas.

Adenocarcinoma, Follicular↗
PubMed1997

[Isolated thyroid nodule. Comparative value of cyto-puncture and scintigraphy].

OBJECTIVES: Nodular thyroid disease, indicated by the presence of single or multiple nodules within the thyroid gland is a common clinical problem, the main question remains the malignancy. Radionuclide scanning, ultrasonography and fine needle aspiration biopsy have been helpful to distinguish benign from malignant nodules and to select patients for surgery. METHODS: We performed a prospective study to assess the comparative value of fine needle nonaspiration biopsy and thyroid scinti scan in the management of 412 patients operated for solitary thyroid nodule. RESULTS: Sensitivity and negative predictive values were the same for both methods, but specificity of cytology was greater than that of thyroid scinti scan (80.53% vs. 10.47%, p < 0.001). DISCUSSION: Thyroid radionuclide scanning remains valuable in the evaluation of a cytological benign solitary thyroid nodule when TSH value is low, in order to distinguish toxic adenoma from cold nodule in Graves' disease.

Adolescent↗
PubMed1996

Migration of metal and polyethylene particles from articular prostheses may generate lymphadenopathy with histiocytosis.

Wear particles released from hip or knee prostheses are known to be involved in the fibrohistiocytic membrane interposed between bone and implant. During surgical treatment for pelvic carcinoma (5 cases) and for isolated pseudomalignant lymphadenopathy (4 cases) lymph nodes in 9 patients who had had lower limb articular replacement were harvested. Light microscopy and image analysis of the nodes showed florid endosinusal histiocytosis, predominant in the cortical area. Using Oil Red O staining and polarized light, metal particles and polyethylene particles were detected in the large histiocytes. Scanning electron microscopy with electron backscattering allowed us to localize metal particles and perform elemental microanalysis. Iron, cobalt, chromium, nickel, zirconium, and barium, known to be used in prosthetic and cementing materials, were identified as component of these particles. Large amounts of polyethylene particles appeared in all cases while metal particles were found to be abundant in only 2 cases. Thus, migration of polyethylene debris from the prosthetic site seems to be the major factor in development of the histiocytes induced in satellite lymph nodes.

Aged↗
PubMed1996

Successful management of an aortoesophageal fistula using a cryopreserved arterial allograft.

We report a case of aortoesophageal fistula occurring as a complication of colonic esophagoplasty. Emergency treatment during the hemorrhagic phase combined aortic replacement using a cryopreserved arterial allograft and digestive tract exclusion. Immediate recovery and follow-up at 8 months were good. This is the first reported case of successful in situ aortic replacement using a cryopreserved allograft for an aortoesophageal fistula. The lack of previous reports of successful treatment and related treatment modalities are discussed.

Adult↗
PubMed1995

Peripheral primitive neuroectodermal tumour after allogeneic bone marrow transplantation.

We report a case of peripheral primitive neuroectodermal tumour (PNET) in a 36-year-old man who 10 years earlier received an allogeneic bone marrow transplantation (BMT) for a non-Hodgkin's lymphoma. Immunohistochemistry proved definitive elimination of a relapse of the original disease and confirmed the diagnosis of PNET. The role of total body irradiation pre-BMT in the genesis of this secondary tumour is discussed. The importance of registering secondary malignant solid tumours after BMT is emphasized. To our knowledge, an Ewing family tumour following BMT has not previously been reported.

Adult↗
PubMed1994

C-cell hyperplasia associated with chronic lymphocytic thyroiditis: a retrospective quantitative study of 112 cases.

Since the first description by Wolfe et al of C-cell hyperplasia (CCH) in asymptomatic relatives of patients suffering from a medullary thyroid carcinoma (MTC), several investigators have described CCH associated with a chronic lymphocytic thyroiditis (CLT) not within the context of MTC or multiple endocrine neoplasia (MEN). We report the study of C-cell density in 112 cases of CLT on retrospective surgical material to determine the frequency of the association between CCH and CLT. The cases of CLT were compared with 19 normal thyroid glands obtained at necropsy. C cells, immunoreactive with a polyclonal anti-calcitonin (CT) antibody, were counted at high magnification (X400) and the number of low-power magnification (X100) microscopic fields (LPFs) containing at least 50 C cells per slide was assessed. Image analysis was performed to determine the C-cell density expressed in number of C cells/cm2. C-cell hyperplasia was defined by the following criteria: C-cell density > 40 cells/cm2 and the presence of at least three LPFs containing more than 50 C cells. Twenty percent of the cases of CLT showed a CCH thus defined, and four of them had an elevated serum CT level. Statistical analysis showed no clinical or biological correlation with the presence of CCH. However, the frequency of CCH was higher if a follicular cell carcinoma was associated with CLT. This study confirms a pathological association between CCH and CLT, provides new criteria for the definition of CCH on surgical pathology material, and reports four cases with an elevated serum CT level not within the context of MTC or MEN.

Adolescent↗
PubMed1994

[Malignant Leydig cell tumor].

A case of malignant Leydig cell tumor is reported. The best feature of malignancy of this rare tumor is the presence of vascular invasion. An immunohistochemical study is presented and the differential diagnosis is discussed.

Adult↗
PubMed1994

[Diffuse sclerosing papillary carcinoma of the thyroid gland. Apropos of a pediatric case of association of an unilateral tumor with diffuse lymphocytic thyroiditis].

A 11-year-old girl presented in 1990 with bilateral goiter, hypothyroidism and thyroid auto-antibodies and was treated for Hashimoto's thyroiditis. In 1991, a cervical lymph node metastasis revealed diffuse sclerosing papillary carcinoma (DSPC) of the right thyroid lobe and chronic lymphocytic thyroiditis of the left lobe. The patient is in remission in 1993 (total follow-up, 39 months). The review of 60 previously reported cases of DSPC shows a predilection for young people, a high incidence of lymph node and pulmonary metastases; however the mortality rate is quite low, reflecting either the good prognosis linked to a young age in papillary thyroid carcinomas, or the short duration of the follow-up preventing assessment of the behaviour of DSPC.

Carcinoma, Papillary↗
PubMed1992

[Nephrogenic nephroma].

Nephrogenic nephroma was individualized by A. Pagès in 1980 as a rare renal neoplasia that mainly occurs in adolescents and adults and presents a benign outcome. The tumor is composed of very small tubular, papillary, and glomeruloid structures. Immunohistochemistry and electron microscopy show that the tumor is a proliferation of primitive epithelial cells that mimic the embryonal nephron. This neoplastic entity has often been confused with a nephroblastoma, although it is a benign tumor that is cured by simple resection. Further studies are needed to define its exact incidence and its histogenesis.

Adolescent↗
PubMed1991

[Chronic autoimmune thyroiditis and C-cell hyperplasia. Study of calcitonin secretion in 24 patients].

Serum calcitonin (CT) was determined by radioimmunoassay, using two monoclonal antisera, in 22 women and two men, who had Hashimoto's thyroiditis as confirmed by echographic, immunological or cytological criteria; in 23 patients, serum CT levels were measured after intravenous infusion of pentagastrin (Pg). In 21 cases, basal and Pg stimulated serum CT concentrations were normal. A 61-year-old woman and a 63-year-old man, both euthyroid, had high serum basal CT: 12 pg/ml and 35 pg/ml; infusion of Pg resulted in abnormal increases in serum CT levels: respectively 64 pg/ml and 115 pg/ml. Another patient, a 65-year-old woman with primary hypothyroidism had high serum basal CT: 90 pg/ml (the Pg stimulation test was not done because of ischemic heart disease). Each of these 3 patients had a total thyroidectomy. Pathological examination of the thyroid showed typical features of Hashimoto's thyroiditis and extensive C-cell hyperplasia. After surgery, serum CT levels fell to normal. Therefore, a high serum CT can be observed as the consequence of C-cell hyperplasia in Hashimoto's thyroiditis.

Adolescent↗