Anti-Helicobacter Pylori, anti-thyroid peroxidase, anti-thyroglobulin and anti-gastric parietal cells antibodies in Czech population

Autoimmune thyropathies are frequently linked to many infections, such as Helicobacter pylori, which are also supposed to play a role in their pathogenesis. The aim of this study was to evaluate the relationships between thyroid and gastric autoimmunity and H. pylori infection on a large sample of Czech population (n=1621) by monitoring the autoantibodies against thyroglobulin (anti-Tg) and thyroid peroxidase (anti-TPO) and gastric parietal cell (anti-GPC, representing thyrogastric syndrome) in correlation with antibodies against Helicobacter pylori (anti-H. pylori) of classes IgG and IgA. The interrelation between autoantibodies and H. pylori antibodies was assessed by H. pylori seropositivity. In H. pylori seropositive persons as compared to seronegative irrespective of age and sex, a higher occurrence of anti-TPO (10.4 % vs. 5.8 %, p=0.001) and anti-GPC (6.1 % vs. 1.7 %, p<0.001) was found. Differences in anti-TPO occurrence were significant in both men (7.0 % vs. 3.3 %, p=0.03) and women (12.7 % vs. 8.0 %, p=0.02), differences in anti-GPC occurrence were significant only in women (7.2 % vs. 1.7 %, p<0.001). Results of this study support the idea of a connection between infection of H. pylori and the occurrence of anti-TPO autoantibodies representing thyroid autoimmunity and gastric parietal cells autoantibodies representing the thyrogastric syndrome.     

Effectiveness of iodine prophylaxis and frequency of thyroid enlargement (thyroid goiter) and clinical diagnosis of thyroid diseases in inhabitants of the Szczecin region after the Czernobyl accident]

The study, supported by program MZ-XVII, was carried on 4567 inhabitants of the area of Szczecin (2350 females and 2217 males). The population was chosen randomly, according to a simple drawing scheme. All subjects were clinically examined using standardised questionnaires. In 3468 persons (including 1807 girls and women, 1661 boys and men) apart form clinical examination, the assessment of thyrotropin, thyroxine and triiodothyronine in serum and frequency of antithyroglobulin antibodies and antithyroid membrane antibodies were evaluated. The data indicate that 94% of children in Szczecin's region received the prophylactic dose of iodine, mostly between the 1st and the 5th of May 1986. Only 17% of the adults received iodine. The most common preparation was Lugol solution given in a single dose. Among all persons who received iodine, only in 5% of subjects the side effects were noted (mostly in children), including symptoms of gastrointestinal tract (vomiting, abdomen pain) and occasionally intrathyroid side effects (thyroid pains). In examined population the high frequency of thyroid enlargement, mainly in women (up to 43-44% at the age group 30-50 years) was found. The frequency of clinical diagnosis of thyroid disease was higher in women than in man (most often the diffuse goiter, rarely the nodular goiter). The frequency of thyroid enlargement and clinical diagnosis of thyroid disease was not dependent on prophylactic iodine intake. The iodine prophylaxis did not influence on thyroid hormones and TSH serum levels and on frequency of antithyroid antibodies.     

Cytologic characterization of postiodization residual goiter in schoolchildren by fine needle biopsy

OBJECTIVE: To determine the relevance and utility of fine needle biopsy (FNB) for providing a tissue-level diagnosis during a community-based survey of postiodization residual goiter in schoolchildren in India. STUDY DESIGN: A total of 14,762 schoolchildren (56.0% girls and 44.0% boys), aged 6-18 years, with a countrywide representation, were clinically screened for the presence of goiter. FNB was performed under field conditions by means of a nonaspiration technique from both lobes of goitrous glands. The cytologic diagnosis and findings were correlated with age, sex, goiter grade and biochemical parameters of serum T4, TSH, thyroid microsomal (TMA) and thyroglobulin (TGA) antibodies. RESULTS: The overall prevalence of goiter was 23.0%, with a greater frequency in girls (27.1%) than boys (17.8%). FNB was successful in 75.6% of subjects without any significant complications. The cytologic diagnoses in 1,312 successful cases were colloid goiter (92.8%), Hashimoto's thyroiditis (4.6%), focal lymphocytic thyroiditis (1.7%) and hyperplastic goiter (0.9%). Autoimmune thyroiditis (AIT), which accounted for only 6.3% cases, showed a strikingly different age-specific prevalence between girls and boys. Serologic markers of TMA and TGA at various titers were observed to lack requisite sensitivity and specificity for establishing an accurate diagnosis of AIT. CONCLUSION: The nonaspiration technique of FNB is capable of yielding valuable diagnostic information during an epidemiologic survey of goiter. The technique can be easily performed under field conditions on children without significant complications. FNB is preferable to serologic markers for accurate diagnosis of AIT. A relatively low frequency of AIT, as observed in the present study, raises the possibility of a significant role of environmental goitrogens as the underlying pathogenetic factor in postiodization residual goiter in Indian schoolchildren.     

Influence of radioactive contamination and iodine prophylaxis after the Czernobyl disaster on thyroid morphology and function of the Poznan region]

The radioactive contamination of Poznań Region was recognized after Chernobyl accident as average. The predicted values of minimal (inhalation) and maximal (inhalation and ingestion) committed dose equivalent to the thyroid varied from 2.5 (min) to 24.7 (max) mSv in different groups of adults and children. To follow up the results of iodine prophylaxis and some aspects of possible thyroid gland morphological and functional changes 11086 persons were carefully investigated clinically and biochemically. Among these 11086 persons were 42.6% males and 57.4% females both adults from 17 till 40 year and children up do 16 years. The following parameters were reviewed: pregnancy, time of residence in the region, thyroid abnormalities, family history concerning thyroid diseases, iodine intake in April and May 1986 with possible side effects, changes in the thyroid size observed before and after 1986, degree and kind of thyroid enlargement, serum concentration of T3, T4, TSH, ATMA and ATG titre and finally the effectiveness of thyroid blockade at 24, 48 and 72 h after ingestion of Lugol's solution. Side effects of the ingestion of potassium iodide from 30-70 mg were observed in 153 cases, 36 of them consulted medical doctors but in no case the side effects (dominated by vomiting) threatened the life. In the investigated group were 144 pregnant women. Majority, because 88% of them delivered the baby on or after time and 6.9% before time, 4.9% of natural abortions were noted but non artificial. In the group of children thyroid gland abnormalities before 1986 were reported in 3 cases in 23 after 1986 it is after Chernobyl accident. This information is interesting but needs more precise analysis of different dependencies occurring. The data obtained indicated the existence in Poznań. Region the goiter endemy because 27.5% of investigated children and adults had goiter classified as grades O-B, I, II and III. The elevation or diminution of T3 values were noted in 1164 cases, for T4 in 418 cases and for TSH in 1412 cases. The presence of antimembrane and antithyroglobulin antibodies were observed in 303 cases. All persons with changes observed in thyroid morphology and function are periodically controlled and the results will be published separately. The investigations performed and results presented concern the early aspects of radioactive contamination and effects of iodine prophylaxis. The answer regarding late effects including thyroid cancer needs further multi year studies for which the clinical material investigated in different parts of Poland and well documented should be used as model group for further periodical studies.     

Anti-thyroid autoantibodies in children with insulin-dependent diabetes mellitus

The study was aimed at the assessment of frequency of occurrence of thyroid antimicrosomal and antithyreoglobuln autoantibodies in children with insulin-dependent diabetes and healthy control children. The occurrence of thyroid autoantibodies was analyzed with respect to the age and sex of children and the duration of the disease. The studied group was composed of 199 children of age between 2 and 17 years with insulin-dependent diabetes. Control group included 100 healthy children. Thyroid autoantibodies were determined by using a solid phase radioimmunoassay. Antimicrosomal antibodies were detected in 35% of diabetic children, but only in 1% of healthy children. Neither in diabetic nor in control children the occurrence of antithyreoglobulin antibodies was significant. The frequency of occurrence of antimicrosomal antibodies was not related to age of children or the duration of diabetes. The occurrence of these antibodies was significantly more frequent in girls (in 70% of cases) than in boys (30% of cases).     

Relationship between thyroid size and urinary concentration of iodine in the population of Bialystok]

The survey carried out in May 1991 in the city of Bia?ystok comprised 308 children of age between 8 and 14 years and 116 young adults. In each of the studied subjects the size of the thyroid was measured by ultrasonography and iodine concentration determined in a randomly voided sample of urine. Body weight and height of the subjects have also been measured. In about 50% of the subjects studied (58.4% of children, 38.5% of men and 58.4% of women) the presence of goiter accompanied by a low urinary iodine concentration (median--2.0 micrograms/ml) was found. A significant negative correlation between the thyroid size and urinary iodine concentration, and lack of relation between the former and TSH concentration, have been found. No relation was observed between the presence of goiter and the inadequate physical development in the children studied. Insignificantly elevated TSH levels without accompanying clinical symptoms of hypothyreosis were observed in 8.7% of children, 3.8% of women and 5.1% of men studied. Higher prevalence of goiter found as compared to the results previously obtained in the same area can be related on the one to the use of more precise methods and on the other to real worsening of the situation due to discontinuation of obligatory iodine prophylaxis in the country more than 10 years ago.     

Ultrasonographic pattern and levels of thyrotropin and antithyroid antibodies in patients with recurrent neutral goiter after subtotal thyroidectomy]

The study comprised 65 women (mean age 43 years) with the recurrent goiter after subtotal strumectomy. All patients were subjected to ultrasonographic examination using a sonograph Sonoline LM (Siemens) with 7.5 MHz head. The study was aimed at: 1) assessment of etiology of goiter recurrence, 2) assessment of changes in the thyroid parenchyma, 3) detection of the occurrence of heterogeneous structures, such as nodules, cysts and calcifications. It was found that goiter recurrence appeared mainly in the patients subjected to surgery because of neutral nodular goiter. The observed changes in the thyroid stump, such as heterogeneous structure of parenchyma, generalized cyst-like spaces and nodular structures mainly of mixed type or of solid, normo-echogenic or hyper-echogenic type, were associated with high levels of THS and the presence of antithyroid antibodies in blood serum. In patients with evidently high TSH levels and positive with respect to occurrence of antithyroid antibodies, the nodular structures were more numerous and of larger size. In can be concluded that ultrasonography provides a valuable noninvasive tool for the evaluation of morphological structure of the recurrent goiter.     

Epidemiology of thyroid diseases in the population of the Sejny community after the atomic catastrophe in Chernobyl]

The survey carried out in 1990 covering the population of Sejny community, sponsored by the Ministry of Health and Welfare, program MZXVII, demonstrated the occurrence of goiter in 33.6% of studied persons. Such an incidence can rightly be recognized as an endemy. Predominance of cases with small or moderate enlargement of the thyroid (OB and I), low percentage of nodules (18%), and 2.8 times more frequent occurrence of goiter in women allows o characterize the endemy as mild. The percentage of goiter in this population does not differ from that found in this area before the Chernobyl disaster. However a small increase in the incidence of thyroid enlargement in a group of boys of age between 17 and 19 years, and an increase in percentage of nodular goiter in whole population was noted. The questionnaire studies confirmed in addition a high effectiveness of mass iodine prophylaxis introduced after the atomic disaster, especially in the population of developmental age. However, because of the latency period concerning the possible effects, the results obtained will be verified in the course of long-term prospective studies.     

Clinical studies on thyroidal autoantibodies.

In an attempt to clarify autoimmune nature of Grave's disease and Hashimoto's thyroiditis, thyroidal autoantibodies have been studied on 86 cases of Grave's disease, 54 cases of Hashimoto's thyroiditis, 31 cases of simple goiter, 11 cases of primary hypothyroidism a-d 22 cases of thyroid neoplasia as well as on 364 healthy subjects. Two kinds of tanned red cell hemagglutination tests were carreid out on each case. One method using refined human thyroglobulin for sensitization of sheep red cells has been found to be specifice for anti-thyroglobulin antibody and to be frequently positive in Hashimoto patients. However, in another method using human thyroidal microsomes (purified by ultracentrifugation) as sensitizing antigen, some heterogenous antibodies including anti-thyroglobulin antibody might be detected together with the antibody against the antigen proper to thyroidal micorsome (HF antigen)which is derived from hyperfunctioning thyroidal follicular cells of Grave's patients. hAnti-HF antibody is frequently detected both in Hashimoto and Grave's patients. In other thyroid diseases the titers of both thyroidal autoantibodies were generally low, though higher than in healthy subjects. The effect of aging on thyroidal autoantibodies in healthy subjects was clearly observed in females but not in males. From the results of these two test, it is possible to speculate that high=columnar and hyperfunctioning thyroidal follicular cells might exist focally in most cases of Hashimoto's thyroiditis.     

Epidemiologic examinations of goiter in the population of the Sejny community]

The study was aimed at the evaluation of incidence of goiter in the population of the community of Sejny. The survey comprising 1520 subjects revealed the presence of thyroid enlargement in 31.8% of the subjects studied, indicating the occurrence of a mild endemy. The facts speaking for this type of endemy are: predominance of cases with goiter of OB or I degree (83%), higher incidence of goiter in women than in men (3.3 times), occurrence of nodular goiter in 12% of cases with goiter, and sporadic appearance of hypothyroidism. Goiter endemy in the population of this area can be attributed to such goitrogenic factors as low level of iodine and high content of calcium in the water, tobacco smoking, and a habit of drinking tap water.     

Titers of antibodies against thyroid membrane antigens in patients with Graves-Basedow disease and progressive infiltrative ophthalmopathy during treatment with glucocorticoids and retro-orbital tissue irradiation]

In 22 patients with progressive endocrine ophthalmopathy (classes 4-6 according to Werner's scale and ophthalmopathy index at least 4 and evidences of infiltrative changes in retro-ocular tissues in computerised tomography, after achievement of euthyroid state) the titers of antibodies against thyroid membrane antigens (ATMA) were determined by Gardas and all. method. Control group consisted of 26 patients with Graves-Basedow disease without clinical signs of ophthalmopathy who were investigated for ATMA before and after conventional methimazole treatment. The determinations of ATMA were performed before treatment, after 3-4 weeks and subsequently once a month. ATMA's titers exceeding 1:1000 were found in 68% of patients with progressive infiltrative ophthalmopathy and in 77% of patients with Graves-Basedow disease without ophthalmopathy. The incidence of elevated ATMA titers during treatment of ophthalmopathy with supervoltage retro-orbital tissues irradiation with high dose of prednisone, decreased markedly in 6th month of treatment with subsequent increase to average 55% at the end of treatment what suggests the influence of therapy on antibodies production. The changes in the incidence of elevated ATMA titers during conventional Graves-Basedow disease treatment were different. No relations between increased ATMA titers and intensity of infiltrative ophthalmopathy and the course of treatment in the patients with ophthalmopathy were found.     

Determination of antithyroid antibodies by an immunoenzymatic method; an adaptation for expressing results in international units]

Solid phase immunoenzymatic methods (ELISA) have been developed for the determination of antithyroglbulin (ATG), antimicrosomal (AMc) and antimembrane (ATMA) antibodies in blood serum. The results have been expressed in international units (IU). The level of nonspecific reaction was determined on the basis of 30 samples of blood serum obtained from healthy donors. The double standard deviation values amounted to 8 IU for antithyroglobulin antibodies, 17 IU for antimicrosomal antibodies and 53 IU for antimembrane antibodies at the serum dilution of 1:100. The values of double standard deviation obtained for the healthy donors correspond to the borderline between the positive serum samples and those containing no autoantibodies. The level of autoantibodies in patients with autoimmune diseases of the thyroid varied considerably ranging from complete absence to several thousand units per milliliter in single cases. Antithyroglobulin antibodies were determined simultaneously by using the described method and the commercial kit (Walker, Cambridge) and the results obtained by the two methods were compared. A linear correlation with the correlation coefficient r = 0.93, p < 0.001 was obtained. A good but nonlinear correlation was demonstrated with the methods expressing the results in titre values.     

Karyopathological traits of thyrocytes and exposure to radioiodines in Belarusian children and adolescents following the accident at the Chernobyl nuclear power plant

The Belarus-American (BelAm) thyroid study cohort consists of persons who were 0-18 years of age at the time of exposure to radioactive iodine fallout from the 1986 Chernobyl nuclear power plant accident and who have undergone serial thyroid screenings with referral for fine-needle aspiration biopsy (FNAB) using standardized criteria. We investigated thyrocyte nuclear abnormalities in cytological samples from FNABs in 75 BelAm subjects with single and multiple thyroid nodules and 47 nodular goiter patients from Leningrad, Russia, unexposed to Chernobyl fallout. Nuclear abnormalities examined included internuclear chromosome bridges and derivative nuclei with broken bridges (i.e., "tailed" nuclei), which are formed from dicentric and ring chromosomes and thus may be cellular markers of radiation exposure. Among subjects with single-nodular goiter, thyrocytes with bridges were present in 86.8% of the exposed BelAm cohort compared with 27.0% of unexposed controls. The average frequency of thyrocytes with bridges and with tailed nuclei was also significantly higher in the BelAm subjects than in controls. Among subjects with multinodular goiters, thyrocytes with bridges were present in 75.7% of exposed BelAm patients compared with 16.7% of unexposed controls; thyrocytes with tailed nuclei were observed in all of the BelAm subjects but in only 40% of controls, and the mean frequencies of bridges and tailed nuclei were significantly higher in the exposed group. Unusually, long bridges were detected in 29% of BelAm patients with single-nodular goiters and 35% of those with multinodular goiters, while no such abnormalities were observed among patients from the Leningrad region. In the exposed subjects from BelAm, we also found positive correlations between their estimated dose of Iodine-131 from Chernobyl fallout and the frequency of tailed nuclei (p = 0.008) and bridges (p = 0.09). Further study is needed to confirm that these phenomena represent consequences of radiation exposure in the human organism.     

Content of thyroglobulin polyribosomes in normal and pathological thyroid cells]

The content of individual thyreoglobulin (TG) polyribosomes in human thyroid gland was studied in healthy persons and in patients with thyroid pathology. The content of TG polyribosomes makes up to 16.2% in normal thyroid tissue and is found to decrease down to 7.8% and 7% under nodal euthyroid goiter and toxic adenoma, respectively. This content is decreased to 12.5% under diffuse toxic goiter and is intermediate between nodal and diffuse toxic goiter under mixed goiter (9.4%).     

Glucose tolerance and incidence of pancreatic islet cell antibodies in pregnancy in women with thyroid autoantibodies

The prevalence of pancreatic islet cell antibodies (ICA) and complement fixing ICA (CF-ICA) and the effect of pregnancy of glucose tolerance was studied in 3 groups of women. One group had thyroid autoantibodies in serum detected in early pregnancy and subsequent development of postpartum thyroiditis (PPT), another group had thyroid autoantibodies without signs of PPT and the third group did not have thyroid autoantibodies or PPT. In the women with thyroid autoantibodies and PPT, ICA were found in one of 12 women (8%, 95% confidence limits 0-38%). In the group with thyroid autoantibodies without PPT, ICA were found in three of 27 women (11%, 2-29%), whereas two of 20 women without thyroid autoantibodies had ICA (10%, 1-32%), N.S. Where present, serum ICA levels were very low and similar in early pregnancy and 6 months postpartum. CF-ICA were only found in two women with thyroid autoantibodies without signs of PPT. In all groups glucose tolerance was impaired in pregnancy when compared to postpartum despite an increased insulin response to glucose ingestion. In pregnancy, however, glucose tolerance was more impaired in the women with thyroid autoantibodies and subsequent PPT, than in the women without thyroid autoantibodies. Postpartum glucose tolerance was similar in all groups. It is concluded, that the presence of thyroid autoantibodies in early pregnancy or development of PPT is not accompanied by an increased prevalence of islet cell antibodies, but women with thyroid autoantibodies and subsequent PPT have a significantly more reduced glucose tolerance in late pregnancy than women without thyroid autoantibodies.     

Postpartum thyroid dysfunction in Mid Glamorgan

A high prevalence of postpartum thyroid dysfunction has been reported in several countries, but there have been no systematic studies of its prevalence in Britain. Among a group of 901 consecutive, unselected pregnant women thyroid autoantibodies were detected in 117 (13%) at booking. The clinical course of postpartum thyroid dysfunction, factors associated with its development, and its likely prevalence were defined in 100 of these women with thyroid antibodies and 120 women with no such antibodies who were matched for age. None of the women had a history of autoimmune thyroid disease. Normal reference ranges for thyroid function during pregnancy and post partum were established in the 120 women negative for thyroid antibodies. On the basis of these observations postpartum thyroid dysfunction was observed in 49 (22%) of the 220 women studied, and the prevalence in the total group of 901 women was estimated to be 16·7%. Thyroid dysfunction, mainly occurring in the first six months post partum, was usually transient and included both destruction induced hyperthyroidism and hypothyroidism. The development of the syndrome was significantly related to smoking more than 20 cigarettes a day and the presence of thyroid microsomal autoantibodies at booking. Of the 16 women with a family history of thyroid disease in whom thyroid microsomal autoantibody activity was detectable at booking, 11 developed thyroid dysfunction. Age, parity, presence of goitre at presentation, duration of breast feeding, and the sex and birth weight of the infant were not associated with the development of postpartum thyroid dysfunction.The mood changes experienced by women post partum may in part be associated with altered thyroid function during this time.     

Genetic Factors in Hashimoto's Struma

It has previously been established that there is a significant history of thyroid disorders in families of patients with Hashimoto''s struma or chronic thyroiditis. In the present study, 99 relatives of 20 patients with Hashimoto''s struma or chronic thyroiditis were studied with regard to the incidence of circulating thyroid autoantibodies; 42 of these 99 relatives were found to have such antibodies. Twenty of the 99 relatives were shown to have thyroid abnormalities (chiefly goitre); of this group of 20, antibodies were found in 12. In the remaining 79 persons (who had no clinical evidence of thyroid disease), 30 were found to have circulating antithyroid antibodies. The incidence of such antibodies among these relatives is very significantly greater than in the general population.From these and other similar studies, there is strong evidence favouring a genetic predisposition for Hashimoto''s struma and chronic thyroiditis. The mode of inheritance is not yet established, and the pathogenesis of the disease has not yet been elucidated.     

Thyroid autoantigens and their relevance in the pathogenesis of thyroid autoimmunity

Humoral and cellular immune responses are both involved in autoimmune disorders of the thyroid gland. In the last five years, new substantial data have been obtained on the nature and the expression of thyroid cell surface autoantigens and on the demonstration of the functional heterogeneity of autoantibodies to the thyroid stimulating hormone (TSH) receptor. In the present report, attention will be mainly focused on recent studies carried out in our laboratory. The main autoantigens so far identified include the 'microsomal' antigen, thyroglobulin and the TSH receptor. For many years the 'microsomal' antigen (M) was considered a poorly characterized constituent of the cytoplasm of the thyroid cell. In the last five years, several lines of evidence were provided indicating that M is also well represented on the surface of the follicular cell and is identical to thyroid peroxidase (TPO). The use of anti-TPO monoclonal antibodies, presently available, have confirmed this antigenic identity. Microsomal (anti-TPO) antibodies are very useful markers of autoimmune thyroid disorders and are generally present in Hashimoto's thyroiditis, idiopathic myxedema and Graves' disease. TSH receptor antibodies (TRAb) are present in the sera of patients with Graves' disease. TRAb are able to stimulate thyroid adenylate cyclase and also to mimic TSH in its thyroid growth stimulation. Thus, these antibodies may have a pathogenetic role in goiter formation and in thyroid hyperfunction in Graves' disease. TRAb were also shown to inhibit both TSH binding to its receptor and TSH-stimulated adenylate cyclase activity. Recently TRAb, which inhibited TSH-stimulated adenylate cyclase activity, were found in idiopathic myxedema patients and may be responsible for impairment of thyroid function.(ABSTRACT TRUNCATED AT 250 WORDS)     

Ultrasound and morphological diagnosis of thyroid diseases in radiation-exposed persons

The purpose of the present investigation was to enhance the efficiency of diagnosis of thyroid diseases in irradiated persons. Three hundred persons exposed to radiation in doses of 5 to 250 SeV and the postexposure period was 9 to 48 years. A control group comprised 100 military men unexposed to ionizing radiation. Thyroid ultrasound study and morphological diagnosis revealed diffuse nodular goiter transformation in 66% of the irradiated persons and malignant thyroid neoplasms in 3.7% whereas 38% of the control patients were found to have only benign diffuse nodular thyroid alterations and autoimmune thyroiditis (AIT). The investigation identified the echosemiotic features of nodular masses and AIT in the study group patients and established their association with the pathomorphological changes of the thyroid. The authors note the high efficiency of complex clinicoradiation and morphological studies in detecting thyroid pathology and the priority in establishing an accurate diagnosis at the preoperative stage and in determining management tactics.     

Thyroid cancer in patients with hyperthyroidism

OBJECTIVE: The coexistence of hyperthyroidism and thyroid cancer is considered a rare event. With the aim of assessing the clinical relevance of this association, we have retrospectively analyzed the incidence of thyroid cancer in 425 hyperthyroid patients seen and treated by surgery in our institutions. METHODS: Among these hyperthyroid patients, we observed 241 (56.7%) cases of multinodular toxic goiter, 120 (28.3%) of uninodular toxic goiter and 64 (15%) cases of Graves' disease. RESULTS: Thyroid cancer was diagnosed in 7 (1.65%) hyperthyroid patients. Histological examination revealed the presence of papillary carcinoma in 5 cases and follicular carcinoma in 2 cases. Neoplasia was detected in 4 patients with nodular toxic goiter and in 3 with uninodular toxic goiter. None of the patients with Graves' disease had thyroid cancer. During the follow-up of 74 months (range 4-154), there were no deaths or any recurrences. CONCLUSION: Although the occurrence of thyroid cancer in hyperthyroid patients is a rare event, the presence of a 'cold' nodule in a hyperfunctioning thyroid should be carefully evaluated to exclude the presence of concurrent malignancy.