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Increased expression of tumor necrosis factor-alpha and decreased expression of thyroglobulin and thyroid peroxidase mRNA levels in the thyroids of iodide-treated BB/Wor rats.

Several lines of evidence suggest that tumor necrosis factor-alpha (TNFalpha) may contribute to the pathogenesis of autoimmune thyroid disease. It is not known, however, whether increased thyroidal TNFalpha levels are associated with changes in thyroid function. The purpose of the present study was to utilize in situ hybridization histochemistry and immunohistochemistry to determine if the expression of TNF-alpha in the thyroid is associated with a decrease in thyroglobulin (Tg) and thyroid peroxidase (TPO) mRNA levels. Lymphocytic thyroiditis was induced in BB/Wor rats by iodide administration, and thyroidal Tg and TPO mRNA levels were assessed by Northern blot analysis and in situ hybridization, and TNFalpha expression by Northern blot analysis and immunohistochemistry. Thyroids were obtained before and 1 and 2 months after iodide administration. Hematoxylin and eosin staining revealed that there was a progressive increase in mononuclear cells in the thyroids of BB/Wor rats ingesting iodide for 1 and 2 months. Northern blot analysis revealed that during the same time course there was a progressive increase in TNFalpha mRNA levels and a progressive decrease in Tg and TPO mRNA levels in the thyroids. In situ hybridization histochemistry was performed to determine if the decrease in Tg and TPO mRNA levels was associated with thyroid follicular cells in contact with infiltrating mononuclear cells. In rats treated with iodide for 1 month, there was a modest decrease in Tg and TPO mRNA levels in follicular cells in contact with infiltrating mononuclear cells. After 2 months of iodide treatment there was clearly a localized decrease in Tg and TPO mRNA levels in follicular cells in contact with infiltrating mononuclear cells. Immunohistochemical analysis did not detect TNFalpha in the thyroids from control rats or from rats treated with iodide for 1 month. In contrast, after 2 months of treatment, TNFalpha was easily detected in infiltrating mononuclear cells and in some thyroid follicular cells. Together, these results suggest that the suppression of Tg and TPO mRNA levels was associated with the expression of TNFalpha and thus are in agreement with in vitro studies demonstrating that TNFalpha inhibits thyroid cell function.

Animals↗

Thyroid hormones and thyroid antibodies in infertile males.

OBJECTIVE: To investigate the incidence of thyroid dysfunction, thyroid antibodies, and the correlation with semen and hormonal parameters in infertile men. DESIGN: Prospective study. SETTING: University-based andrology laboratory. PATIENT(S): Three hundred five infertile men with idiopathic infertility. INTERVENTION(S): Medical history, clinical examination, semen analysis, measurement of free thyroxin (fT4), free triiodothyronine (fT3), basal thyroid-stimulating hormone (bTSH), LH, FSH, T, free testosterone (fT), PRL, E2, sex hormone-binding globulin (SHBG), DHEAS, and the thyroid antibodies thyreoglobulin antibody (TGA), thyroid peroxidase antibody (TPO-Ab), and thyroid receptor antibody (TRAK). MAIN OUTCOME MEASURE(S): Incidence of thyroid dysfunction and thyroid antibodies, as well as the correlation with hormones and the results of semen analyses. RESULT(S): No manifest thyroid dysfunction was observed. Latent thyroid dysfunction and latent hypothyroidism were diagnosed in 11.5% and 3% of infertile men, respectively. No correlation between thyroid dysfunction and semen parameters was detected. bTSH correlated significantly with PRL (P<.001). Thyroid antibodies were elevated in 7.5%. Elevated TPO-Ab were significantly correlated with pathozoospermia (P=.036) and asthenozoospermia (P=.049). CONCLUSION(S): Latent thyroid dysfunction had no impact on semen parameters. In patients with elevated TPO-Ab levels, pathozoospermia or asthenozoospermia should be considered.

Adult↗

Thyroid hormone receptors and type I iodothyronine 5'-deiodinase activity of human thyroid toxic adenomas and benign cold nodules.

The majority of thyroid adenomas are of clonal origin. In a subset of toxic adenomas (TAs) and cold nodules (CNs) activating mutations in the thyrotropin (TSH) receptor or G s -alpha gene may explain the altered functions in these benign tumours. The present study was undertaken to investigate the status of functional thyroid hormone receptors, major thyroid hormone signal mediators, in both the human TAs and CNs in comparison with a normal thyroid tissue from the same patient. Electrophoretic mobility shift assays using a DR4 ("direct repeats" 4), a thyroid hormone responsive element (TRE) of human type I iodothyronine 5'-deiodinase demonstrated the DNA-binding of thyroid hormone receptors (TRs) in thyroid tissue nuclear extracts. A significant increase (p < 0.05) in the functional binding properties of TRs to the DR4 thyroid hormone responsive element was found in TAs when compared to normal thyroid tissue. Contrary, a marked diminution in the TR-TRE complex formation was found in CNs in comparison with normal thyroid tissue. In addition, functional activity of the iodothyronine 5'-deiodinase (5'DI) was analyzed in benign tumours, thyroid TAs and CNs in comparison with that of normal thyroid tissue. A significantly increased (p < 0.01) activity of 5'DI was demonstrated in TAs, and in contrast, decreased values of the enzyme activity were found in CNs when compared to a normal tissue. From the data it is suggested that both the status of TR-TRE complex formation and the activity of the 5'DI may be altered in benign tumours of human thyroid gland.

Adenoma↗

Routine measurement of serum calcitonin is useful for early detection of medullary thyroid carcinoma in patients with nodular thyroid diseases.

BACKGROUND: Medullary thyroid carcinoma (MTC) is characterized by a high concentration of serum calcitonin. Routine measurement of serum calcitonin concentration has been advocated for detection of MTC among patients with nodular thyroid diseases. However, a minimal to moderate increase of serum calcitonin concentration has been frequently observed in diseases other than MTC. Fine-needle aspiration cytology (FNAC) is not a reliable method for detection of MTC. Therefore, we evaluated the usefulness of routine measurement of serum calcitonin concentration in patients with nodular thyroid diseases, and studied the validity of pentagastrin stimulation test and FNAC in these patients. SUBJECTS AND METHODS: We performed routine measurement of serum calcitonin concentrations in 1,448 patients (male, 285, female, 1,163) with nodular thyroid diseases. The average age was 46 years (range, 14-86 years). Initial examination included thyroid examination, thyroid scan or ultrasonography, measurements of serum free triiodothyronine) (T3), free thyroxine (T4), thyrotropin (TSH) levels, and antithyroid autoantibodies. FNAC was performed in all patients who had palpable or visible thyroid nodule by ultrasonography, and pentagastrin stimulation test was performed in 39 patients who consented. Serum calcitonin concentration was measured with a two-site immunoradiometric assay using commercial kits. We also measured the serum calcitonin concentration in 407 healthy subjects without thyroid or nonthyroid diseases. RESULTS: Serum calcitonin concentration was 10 pg/mL or less in 403 normal subjects (99.0 percentile), and 11-13 pg/mL in the remaining 4 subjects. We found that 56 (3.87%) of 1,448 patients with nodular thyroid diseases had serum calcitonin level above 10 pg/mL. Ten patients (0.69%) with histologically confirmed MTC were detected by the routine measurement of serum calcitonin. The prevalence of MTC was 5.2% in 194 patients with thyroid carcinoma. Five of 10 patients with MTC had basal serum calcitonin level above 100 pg/mL. The remaining 5 patients had minimal or moderate elevation of basal serum calcitonin (range, 12-86 pg/mL). Serum calcitonin concentration increased to more than 100 pg/mL by pentagastrin in all patients with MTC (2.4- to 37.7-fold increase). FNAC suggested MTC in only 2 patients (22.2%), and failed to diagnose MTC in 7 patients. FNAC was not performed in 1 patient with MTC, because he had no visible mass by ultrasonography. CONCLUSION: These results suggested that routine measurement of serum calcitonin is useful in the early detection of MTC among patients with nodular thyroid diseases. Pentagastrin stimulation test may also be a reliable way for evaluating thyroid nodular patients with mild or moderate elevation of serum calcitonin concentrations. However, FNAC was not sensitive in detecting MTC. We recommend routine measurement of serum calcitonin concentration in patients with nodular thyroid diseases.

Adolescent↗

Increase in thyroid follicular cell tumors in nelfinavir-treated rats observed in a 2-year carcinogenicity study is consistent with a rat-specific mechanism of thyroid neoplasia.

The carcinogenic potential of nelfinavir mesylate (nelfinavir) was evaluated in a 2-year oral (gavage) study on Sprague-Dawley rats at dose levels of 0 (control), 0 (vehicle control), 100, 300 and 1000 mg/kg per day. At the end of the treatment, increased incidences of thyroid follicular cell hyperplasia and neoplasms were observed at 300 (males) and 1000 mg/kg per day (both sexes). There were no other treatment-related effects and no tumors at other sites. Results from previous studies indicated a number of effects in the liver and thyroid, as well as metabolic profiles that suggested nelfinavir might cause thyroid hyperplasia/neoplasia secondary to hormone imbalance by altering thyroid hormone disposition. To investigate this hypothesis, the effects of nelfinavir on gene expression in rat hepatocytes and liver slices (in vitro), thyroxine plasma clearance, and thyroid gland function were evaluated. Compared to controls, gene expression analyses demonstrated an increased expression of glucuronyltransferase (UDPGT) and CYP450 3A1 in nelfinavir-treated rat hepatocytes and liver slices. In rats treated with nelfinavir (1000 mg/kg per day) for 4 weeks, liver weights and centrilobular hepatocellular hypertrophy were increased and minimal to mild diffuse thyroid follicular cell hypertrophy and follicular cell hyperplasia were evident in the thyroid gland. Thyroid-stimulating hormone (TSH) levels were significantly increased (three-fold), while tri-iodothyronine (T3)/tetra-iodothyronine (T4) and reverse T3(rT3) levels were unchanged, indicating that a compensated state to maintain homeostasis of T3/T4 had been achieved. Plasma 125I-thyroxine clearance was increased and the plasma thyroxine AUC0-48 was decreased (24%) compared to control. In conclusion, these data indicate that thyroid neoplasms observed in the nelfinavir-treated rats were secondary to thyroid hormone imbalance. Increased thyroxine clearance contributes to the effects of nelfinavir on thyroid gland function and is probably a result of UDPGT induction that leads to elevated TSH levels in the rat and eventual thyroid neoplasia. These results are consistent with a well-recognized rat-specific mechanism for thyroid neoplasms.

Adenocarcinoma, Follicular↗

A sensitive and practical assay for thyroid-stimulating antibodies using FRTL-5 thyroid cells.

A sensitive, precise and practical assay for thyroid stimulating antibodies was developed in which poorly differentiated rat thyroid cells (FRTL-5) were exposed to crude immunoglobulin fractions precipitated from serum with 15% polyethylene glycol under hypotonic conditions. After the incubation at 37 degrees C for 2 h, cAMP released into Hank's medium without NaCl was determined by radioimmunoassay. The removal of NaCl from the isotonic Hank's medium greatly enhanced cAMP production in response to both TSH and thyroid stimulating antibodies. The assay was sensitive enough to elicit an approximately 30-fold increase in cAMP at 10 mU/l bovine TSH. Thyroid stimulating activities measured using FRTL-5 cells significantly correlated with those measured using cultured porcine (r = 0.918, N = 72) or human (r = 0.830, N = 23) thyroid cells. Thyroid stimulating activities were detected in all of the 50 patients with hyperthyroid Graves' disease, the 14 patients with recurrent hyperthyroid Graves' disease, and the 25 patients with ophthalmic Graves' disease. Thyroid stimulating activity was also detected in some patients (9/24, 37.5%) with Hashimoto's thyroiditis whose serum TSH concentrations were higher than 30 mU/l. However, it was completely abolished by pre-treatment of the sera with anti-TSH antibodies. Although thyroid stimulating activities were detected in one of the patients with simple goitre (N = 10) and in one with thyroid cancer (N = 10), none of the patients with silent thyroiditis (N = 7), adenomatous goitre (N = 11), and thyroid adenoma (N = 9) were positive for thyroid stimulating antibodies.

Animals↗

The association between hypoechogenicity or irregular echo pattern at thyroid ultrasonography and thyroid function in the general population.

OBJECTIVE: Patients with overt hypothyroidism show decreased echogenicity of the thyroid at ultrasonography (US). The aim of this study was to investigate the association between echogenicity of the thyroid/irregular echo pattern, and thyroid function in the general population, i.e. subjects without overt thyroid disease. DESIGN: A cross-sectional investigation of 4649 randomly selected adult subjects. METHODS: Blood samples were analysed for serum TSH, thyroid hormones and thyroid autoantibodies. US of the thyroid was performed. RESULTS: Participants with decreased echogenicity (n=379) had a higher mean TSH (1.65 mU/l) compared with subjects with normal echogenicity (1.21 mU/l, P<0.0001). The association was stronger in subjects with markedly decreased echogenicity (4.20 mU/l, P<0.0001). A similar association was seen when the subjects were divided into subgroups according to the level of TSH; more subjects with high levels of TSH had decreased echogenicity (P<0.0001). Likewise, more subjects with high levels of TSH had an irregular echo pattern (P<0.0001). Subjects with decreased echogenicity had a higher risk of having thyroid autoantibodies than subjects without decreased echogenicity (P<0.0001). This association was stronger when echogenicity was markedly decreased. CONCLUSIONS: We demonstrated an association between hypoechogenicity at thyroid US and higher levels of serum TSH even in subjects without overt thyroid disease, suggesting decreased echogenicity as an early sign of thyroid dysfunction. Irregular echo pattern, whether accompanied by hypoechogenicity or not, was another possible marker of thyroid failure. This indicates a possible use of thyroid US in detecting early and subclinical thyroid dysfunction.

Adolescent↗

Thyroid cancer with coexistent Hashimoto's thyroiditis. Clinical assessment and management.

Hashimoto's thyroiditis is a common thyroid disorder. Because of the difficulty of diagnosing a coexisting thyroid cancer, its management remains controversial. We reviewed 120 cases of thyroid cancer seen in our institution during an 11-year period (1976 through 1986) and defined the clinical characteristics of patients with both entities. Thirteen patients had concomitant cancer and Hashimoto's thyroiditis. Six of the 13 patients had a history of thyroiditis before the diagnosis of thyroid cancer. The remaining seven patients had evidence of Hashimoto's thyroiditis on histologic review of the thyroid specimen. The two most common characteristics prompting surgical intervention were the presence of a nonsuppressing dominant nodule and a cold area on thyroid scan. Twelve patients underwent preoperative fine-needle aspiration cytologic examination, but only in three were the results considered to be indicative of cancer. All 13 patients remained disease free. Despite the apparent indolence of thyroid cancer associated with Hashimoto's thyroiditis, selective surgical treatment of patients with clinical thyroiditis is indicated.

Adult↗

Functional insulin receptors are overexpressed in thyroid tumors: is this an early event in thyroid tumorigenesis?

BACKGROUND: Insulin receptor (IR), a member of the receptor tyrosine kinase family, is expressed in normal thyroid cells and affects thyroid cell proliferation and differentiation. METHODS: The authors measured IR content in benign and malignant thyroid tumors by three independent methods: a specific radioimmunoassay, 125I-insulin binding studies, and immunohistochemistry. The results obtained were compared with the IR content in paired, adjacent, normal thyroid tissue. To assess IR function in thyroid carcinoma cells, glucose uptake responsiveness to insulin was also studied in a human transformed thyroid cell line (B-CPAP) and in follicular carcinoma cells in primary culture. RESULTS: In 9 toxic adenomas, the average IR content was similar to that observed in the 9 paired normal thyroid tissue specimens from the same patients (2.2+/-0.3 vs. 2.1+/-0.3). In 13 benign nonfunctioning, or "cold," adenomas, the average IR content was significantly higher (P < 0.001) than in paired normal tissue specimens (4.3+/-0.5 vs. 1.8+/-0.1). In 12 papillary and 10 follicular carcinomas, IR content was significantly higher (P < 0.001) than in the adjacent normal thyroid tissue (4.0+/-0.4 vs. 1.6+/-0.2 and 5.6+/-1.0 vs. 1.8+/-0.2, respectively). The finding of a higher IR content in benign "cold" adenomas and in thyroid carcinomas was confirmed by both binding and immunostaining studies. CONCLUSIONS: The current studies indicate that 1) IR content is elevated in most follicular and papillary differentiated thyroid carcinomas, and 2) IR content is also elevated in most benign follicular adenomas ("cold" nodules) but not in highly differentiated, hyperfunctioning follicular adenomas ("hot" nodules), which very rarely become malignant. This observation suggests that increased IR expression is not restricted to the thyroid malignant phenotype but is already present in the premalignant "cold" adenomas. It may contribute, therefore, to thyroid tumorigenesis and/or represent an early event that gives a selective growth advantage to transformed thyroid cells.

Cells, Cultured↗

Decreased uptake of therapeutic doses of iodine-131 after 185-MBq iodine-131 diagnostic imaging for thyroid remnants in differentiated thyroid carcinoma.

We performed a prospective random study to assess possible thyroid stunning by a 185-MBq iodine-131 dose used to diagnose thyroid remnants. Patients with differentiated thyroid carcinoma were included after total or near-total thyroidectomy. They were randomly assigned to two groups. In group 0 (G0, 32 patients), iodine-123 administration only was used to diagnose thyroid remnants and/or metastasis, so that no thyroid stunning by 131I would occur. In group 1 (G1, 19 patients), diagnostic imaging was performed with 123I and 185 MBq 131I. 123I imaging was less sensitive than 131I imaging in identifying thyroid remnants in both groups (94%). Thyroid uptake of 123I was measured in both groups (at 2 h) and was not significantly different between the groups. Patients with thyroid remnants who remained in the study (28/32 in G0, 17/19 in G1) were treated with 370 MBq 131I, 5 weeks after treatment (mean time, range 12-84 days). In 12/17 G1 patients thyroid uptake measurement was repeated immediately before treatment. Uptake was equal to 1.97% +/- 0.71% and significantly lower (P < 0.05) than the previous measurement (3.76% +/- 1.50%). Patients were imaged 7 days after administration of the therapeutic dose and the images were compared with the diagnostic images. In 28/28 G0 patients thyroid remnants were unchanged and clearly seen. In 5/17 G1 patients, however the remnants were hardly identified, although they had been clearly seen at the time of diagnosis. We conclude the following: (1) a diagnostic dose of 185 MBq 131I decreases thyroid uptake for several weeks after administration and can impair immediate subsequent 131I therapy; (2) 123I is slightly less sensitive than 131I in identifying thyroid remnants; and (3) the need to scan for thyroid remnants remains to be confirmed, since only 2/51 patients enrolled in this study were not treated with 131I.

Carcinoma, Papillary↗

Thyrothymic thyroid rests: incidence and relationship to the thyroid gland.

BACKGROUND: Rests of thyroid tissue within the thyrothymic area are relatively common and might be of clinical importance. The purpose of this study is to define the incidence and anatomy of thyroid tissue located in the line of the thyrothymic ligament, referred to here as "rests." STUDY DESIGN: Prospective descriptive intraoperative evaluation of 100 consecutive thyroid or parathyroid procedures was undertaken to identify the incidence and anatomical location of thyrothymic thyroid rests. Photographs and histologic confirmation of the thyroid remnants were obtained. RESULTS: One hundred eighty sides of the thyroid gland are examined in 100 consecutive patients. Thyroid rests in the thyrothymic area were found in 53 patients, or on 83 separate sides of the thyroid (46%). In patients who had rests identified, 30 (57%) had bilateral rests, with 16 (30%) only on the right, and 7 (13%) only on the left. Eighty percent of identified rests were still attached to the thyroid proper by a pedicle of thyroid tissue but 20% were entirely separate. Most rests were small, with 88% being less than 1 cm in diameter. CONCLUSION: Rests of thyroid tissue within the thyrothymic area, either as entirely separate nodules or as prolongations from the thyroid lobe, are relatively common and might be of clinical importance during thyroid or parathyroid surgery.

Adolescent↗

Effects of excess iodine administration on thyroid function in euthyroid patients with a previous episode of thyroid dysfunction induced by interferon-alpha treatment.

OBJECTIVE: To determine the effects of pharmacological quantities of iodide (SSKI) on thyroid function in euthyroid patients previously treated with recombinant interferon-alpha (rIFN-alpha) for chronic viral hepatitis B and C (HCV), a cytokine which may induce thyroid dysfunction. DESIGN: Thyroid function tests were carried out in 16 euthyroid patients, 8 of whom had previously developed thyroid dysfunction during rIFN-alpha therapy for HCV, before, during and after the administration of 10 drops of saturated solution of potassium iodide (SSKI) (approximately 350 mg iodide). PATIENTS: All 16 patients had been treated in the past with rIFN-alpha for HCV. Eight patients had developed rIFN-alpha induced abnormalities in thyroid function (5 inflammatory thyrotoxicosis, 1 Graves' disease, and 2 impaired thyroid organification of iodide) and 8 had not developed thyroid dysfunction. MEASUREMENTS: After baseline serum free T4 (FT4) and free T3 (FT3) concentrations, basal and TRH stimulated TSH concentrations, and TSH-receptor (TSH-R-Ab) and thyroid peroxidase (TPO-Ab) antibodies were measured, 10 drops saturated solution of potassium iodide (SSKI, approximately 350 mg iodide) were given daily for 60 days and the above parameters assessed during and after SSKI was discontinued. RESULTS: Five of 8 patients with a previous history of rIFN-alpha induced thyroid dysfunction developed mild iodide induced abnormalities of thyroid function (subclinical hypothyroidism (slightly elevated basal and TRH stimulated serum TSH concentrations with normal serum FT4 and FT3 concentrations) or hyperthyroidism) compared with the 8 patients who had no previous evidence of thyroid dysfunction during rIFN-alpha therapy. CONCLUSIONS: In view of the present observations, it is prudent to avoid the administration of excess iodine to euthyroid subjects with a previous episode of thyroid dysfunction during rIFN-alpha therapy, adding a new group of patients susceptible to iodine induced thyroid disease.

Adult↗

Is there an association between life events, postnatal depression and thyroid dysfunction in thyroid antibody positive women?

BACKGROUND: Postnatal depression is more common in women positive for thyroid autoantibodies, independent of thyroid hormone dysfunction, but the basis of this association is unclear. AIMS: The objective of the work reported here has been to investigate from data obtained from previously published research, a possible association between life events, postnatal depression and the development of thyroid dysfunction in women who are positive for thyroid autoantibodies. METHOD: A cohort of pregnant women whose thyroid antibody status was positive (N = 115), was identified at antenatal booking (approximately 16 weeks). These, and a group of women negative for thyroid antibodies (N = 123), were assessed for depression at six to eight weeks postpartum and then at 12, 20 and 28 weeks postpartum according to Research Diagnostic Criteria (RDC). The number and type of life events over the preceding year were also assessed at eight weeks postpartum using Paykel's Life Event Schedule. At four weekly intervals post-partum until six months, thyroid antibody levels and thyroid function (plasma T3 T4 and TSH) were measured. RESULTS: As anticipated, the thyroid antibody status remained the same throughout the study, and there was no difference in the number or type of life events reported in the preceding year, between antibody positive and antibody negative women. Postnatal depression was associated with an excess of both total and negative life events, independent of thyroid antibody status or actual thyroid hormonal status. Women who developed thyroid dysfunction did not report an excess of life events (total, negative or neutral) in the preceding year. CONCLUSION: There was an excess of reported total and negative life events in women with postnatal depression, but this was independent of thyroid antibody status or function.

Autoantibodies↗

RET/papillary thyroid cancer rearrangement in nonneoplastic thyrocytes: follicular cells of Hashimoto's thyroiditis share low-level recombination events with a subset of papillary carcinoma.

CONTEXT: RET/papillary thyroid cancer (PTC) is a marker for papillary thyroid carcinoma, but its specificity has been questioned because of the disputed identification of RET/PTC in Hashimoto's thyroiditis (HT), oncocytic tumors, and other thyroid lesions. OBJECTIVE: The objective of this study was to determine 1) whether RET/PTC occurs in nonneoplastic follicular cells of HT, and 2) its recombination rate in thyroid tumors. DESIGN/PATIENTS: Forty-three samples from 31 cases of HT were examined using interphase fluorescence in situ hybridization (FISH) with RET probes spanning the breakpoint region; real-time RT-PCR to quantify RET/PTC1, RET/PTC3, and c-RET transcripts; and RT-PCR after laser capture microdissection to enrich samples for follicular cells. The results were compared with those similarly obtained in 34 papillary carcinomas, eight thyroid oncocytic tumors, and 21 normal thyroids. RESULTS: Normal samples showed no RET rearrangement. Sixty-eight percent (15 of 22) of HT were positive by FISH; in all thyroiditis, signals were localized to rare nonneoplastic follicular cells; low-level RET/PTC was identified in 17% (five of 29) of thyroiditis cases by real-time RT-PCR and in an additional six of 11 real-time negative cases after increasing sensitivity with laser capture microdissection. Low RET/PTC1 levels were detected in 26% (nine of 34) of papillary carcinomas with an expression pattern and proportion of FISH-positive cells similar to those of the thyroiditis. Forty-seven percent (16 of 34) of papillary carcinomas and one oncocytic carcinoma expressed high RET/PTC1 mRNA levels. CONCLUSIONS: Low-level RET/PTC recombination occurs in nonneoplastic follicular cells in HT and in a subset of papillary thyroid carcinomas. RET/PTC expression variability should be taken into account for the molecular diagnosis of thyroid lesions. Overlapping molecular mechanisms may govern early stages of tumor development and inflammation in the thyroid.

Carcinoma, Papillary↗

Association of melasma with thyroid autoimmunity and other thyroidal abnormalities and their relationship to the origin of the melasma.

Melasma is localized hyperpigmentation over the forehead, upper lips, cheeks, and chin. In this study, evidence suggesting an association between autoimmune thyroid disorders and melasma and the relationship of thyroid disorders to the origin of melasma is presented. A total of 108 nonpregnant women, aged 20-56 yr, were divided into 2 groups for the purpose of this study: 1) melasma, 84 patients; 2) control group, 24 patients from the Dermatology Clinic matched for age and sex. Microsomal thyroid autoantibodies (MCHA) were sought in all subjects. TRH-TSH tests were performed in patients with melasma and in those women with goiter and/or positive MCHA tests from the control group. Studies were completed with serum T4, T3, and antithyroglobulin antibody (TGHA) measurements in all patients with thyroid abnormalities. In patients with melasma, the frequency of thyroid disorders (58.3%) was 4 times greater than in the control group. The MCHA-negative patients had 1) simple goiter (13.1%), 2) Plummer's disease (2.4%), and 3) TSH hyperresponse to TRH in nongoitrous patients (10.7%). Patients with positive MCHA tests (32.1%) were divided into 2 subgroups. One comprised those women with an apparently normal thyroid gland and thyroid function (n = 7), while the other included all patients with goiter and/or subclinical hypothyroidism (n = 20). Regarding the origin of the melasma, it was found that 70% of women who developed melasma during pregnancy or while using oral contraceptives had thyroid abnormalities compared to 39.4% of patients with idiopathic melasma. Subjects from the control group had a 12.5% incidence of thyroid abnormalities, and only 8.3% had positive MCHA. Estrogen, progesterone, or both could be the triggering factor in the development of melasma in women who have a particular predisposition toward both melasma and thyroid autoimmunity. Patients with idiopathic melasma had a lower frequency of thyroid abnormalities, suggesting that there may be different genetic patterns linked to autoimmune thyroid disease. We conclude that there is a true association between thyroid autoimmunity and melasma, mostly in women whose melasma develops during pregnancy or after ingestion of oral contraceptive drugs.

Adult↗

Monoclonal gammopathy in Hashimoto's thyroiditis and malignant lymphoma of the thyroid.

Serum protein electrophoresis was performed in 681 patients (43 men and 638 women) with an initial diagnosis of Hashimoto's thyroiditis between April and November 1983. All patients whose thyroid size was estimated to be greater than 50 g underwent biopsy; 1 man was found to have thyroid prelymphoma, and 13 patients (4 men and 9 women) were found to have malignant lymphoma of the thyroid. Monoclonal gammopathy (M-component) was demonstrated in 5 of 667 patients (0.7%) with Hashimoto's thyroiditis (1 man and 4 women), 1 man with thyroid prelymphoma, and 3 of the 13 patients (23.1%) with malignant lymphoma of the thyroid (2 men and 1 woman). Intracytoplasmic monoclonal immunoglobulin was found in the 1 thyroid prelymphoma and in all 3 malignant lymphoma of the thyroid in patients who had M-component in their serum, but not in thyroid tissue from any of the 5 patients with Hashimoto's thyroiditis who had M-component in their serum. Thus, the finding of monoclonal intracytoplasmic immunoglobulin in tissue sections permitted the diagnosis of malignant lymphoma of the thyroid or thyroid prelymphoma.

Adult↗

Post-Chernobyl thyroid carcinoma in Belarus children and adolescents: comparison with naturally occurring thyroid carcinoma in Italy and France.

After the Chernobyl nuclear accident (April 26, 1986), childhood thyroid carcinoma had a great increase in Belarus and Ukraine, as a consequence of the exposure to iodine radioactive fallout. The epidemiological and clinical features of the disease were studied in 472 patients less than 21 yr old at diagnosis, with differentiated thyroid carcinoma, representing 97.7% of all thyroid carcinomas diagnosed in Belarus between May, 1986, and December, 1995. The results were compared with those of 369 subjects of the same age group, with naturally occurring thyroid carcinoma, observed in Italy and France. Between 1986 and 1989, the number of thyroid cancer cases per year ranged from 3-8 and increased to 31 in 1990, to 66 in 1991, to 72 in 1992, to 93 in 1993, to 96 in 1994, and to 90 in 1995. The age at diagnosis was 14 yr or less in 78.8% (children group) and more than 14, but less than 21, yr in the remaining subjects (adolescents group). Mean (+/- SD) age at the time of the accident was 4.4 +/- 3.4 yr (3.2 +/- 2.3 in children and 8.9 +/- 2.7 in adolescents), the majority of the patients (62.9%) being 5 yr old or less. The time interval between the accident and the diagnosis (latency period) decreased progressively from 7.5 +/- 1.6 yr in children 0-2 yr old at the time of the accident to 6.0 +/- 1.6 yr in those 9-11 yr old. Since 1993, the yearly distribution of new cases showed a decrease in the subjects 9 yr old or more at the time of the accident but not in those 5 yr old or less. This could not be accounted for by a shift of exposed subjects to an age group at diagnosis not included in this study, because only subjects less than 12 yr of age at the time of the accident were considered in this analysis. Mean age at diagnosis in Belarus patients was 11.3 +/- 3.1 yr (10.1 +/- 2.3 in children and 15.7 +/- 1.4 in adolescents), whereas, among patients with naturally-occurring thyroid carcinomas from Italy and France, the majority of cases were diagnosed after 14 yr of age (mean age at diagnosis: 14.6 +/- 4.2 yr). The female-to-male ratio was significantly higher in Italy and France (2.5/1), compared with the ratio of patients from Belarus (1.6/1). Most of the tumors were papillary in both series, but a relatively high proportion of follicular carcinomas (P = 0.0001) was found in Italy/France (15.2%), as opposed to 5.3% in Belarus. Extrathyroidal extension and lymph node metastases were more frequent in Belarus (49.1%, P = 0.0001; and 64.6%, P = 0.002, respectively) with respect to Italy/France (24.9% and 53.9%, respectively). Thyroid lymphocytic infiltration and circulating antithyroperoxidase antibody were more frequent in Belarus patients. Our analysis of Belarus thyroid cancer patients less than 21 yr old showed that the post-Chernobyl increase in thyroid carcinomas involved both children and, to a much lesser extent, adolescents. Subjects 5 yr old or less at the time of the accident accounted for the majority of the patients. No evidence of a decrease in the number of new cases was observed in this age group, as opposed to older subjects. These data support the concept that subjects who were younger at the time of radiation exposure had, and continue to have, a greater risk of developing thyroid carcinoma and strongly suggest that this age group should be carefully monitored in the future. When compared with naturally occurring thyroid carcinoma of the same age group observed in Italy and France, the post-Chernobyl Belarus thyroid carcinomas affected younger subjects, were less influenced by gender, were virtually always papillary, had a greater aggressiveness at presentation, and were more frequently associated with thyroid autoimmunity.

Adenocarcinoma, Follicular↗

Thyroid autoantibodies in thyroid cancer: incidence and relationship with tumour outcome.

In the present investigation we studied serum anti-thyroglobulin and anti-thyroid microsomal autoantibodies, measured by hemagglutination technique, in 600 patients with thyroid cancer seen by us from 1975 to 1985 (mean follow-up 46 months). Positive thyroglobulin antibodies and/or microsomal antibodies were found in 138 (23%) patients (23.9% with papillary, 25% with follicular, 16.1% with anaplastic, and 4.1% with medullary thyroid carcinomas). The incidence of positive tests was similar in each decade of life (ranging between 21.9% and 27.9%), whereas in a normal sex-matched population with no evidence of thyroid disease, the frequency of positive tests was very low in young people and increased to 23% in people older than 60. In 64 patients with no evidence of residual or metastasic thyroid tissue after surgery and radioiodine, initially positive antibody titres became negative in 54.6%, decreased in 32.8%, did not change in 3.1%, and increased in 9.3%. On the contrary, antibody titres of patients with persistent disease became undetectable in 8.3%, decreased in 16.6%, remained unchanged in 25%, and increased in 50%. The clinical course of differentiated thyroid cancer was unaffected by the presence of thyroid antibodies and no difference was found in the death rate between antibody-positive and antibody-negative patients (11.5% and 13.6%, respectively). In conclusion, our data indicate that: 1) autoimmune phenomena are not an infrequent finding in thyroid cancer; 2) as in non-malignant thyroid diseases, positive-antibody tests are more frequently observed in females than in males; 3) at variance with normal controls, no age-dependent increase in serum anti-thyroid antibodies was found in thyroid cancer; 4) the presence of metastatic thyroid tissue seems to be necessary to perpetuate the autoantibody synthesis, and 5) anti-thyroid autoantibodies are not a protective or worsening factor in the tumour outcome.

Adolescent↗