Hyperthyroidism and Concurrent Thyroid Cancer

Multifocal papillary thyroid cancer in Graves' disease: A case report

BACKGROUND

Thyroid cancer is not commonly observed in patients with Graves' disease (GD). The presence of thyroid nodules in GD is not uncommon. However, a link between these two entities has been reported. Herein, we report the case of a patient with GD and thyroid cancer in Saudi Arabia, which has not been reported previously in our region.

CASE SUMMARY

A 26-year-old male patient with GD, receiving carbimazole for 2 years, presented to our hospital. His hyperthyroidism was controlled clinically and biochemically. On clinical examination, he was found to have a left-sided thyroid nodule. Ultrasound revealed a 2.6 cm hypoechoic nodule with high vascularity. He was then referred for fine needle aspiration which showed that the nodule was highly suspicious for malignancy. The patient underwent total thyroidectomy and was diagnosed with multifocal classical micropapillary thyroid cancer. Post thyroidectomy he received radioactive iodine ablation along with levothyroxine replacement therapy.

CONCLUSION

Careful preoperative assessment and thyroid gland ultrasound might assist in screening and diagnosing thyroid cancer in patients with GD.

A systematic review of the incidence of thyroid carcinoma in patients undergoing thyroidectomy for thyrotoxicosis

INTRODUCTION

Hyperthyroidism (HT) has been associated with no insignificant rates of thyroid malignancy. There are no current specific guidelines that suggest routine preoperative imaging for thyroid nodules in patients with Grave's disease. We therefore performed a systematic review assessing rates of thyroid malignancy in patients undergoing surgery for different causes of HT: Grave's disease (GD), toxic adenoma (TA) and toxic multinodular goitre (TMNG).

METHODS

Major databases (MEDLINE, PubMed and the Cochrane library) were searched to identify eligible studies.

RESULTS

After searching and appraising, 33 papers were found to be eligible for analysis. The mean overall rate of malignancy was 8.5% (range 0.8%-32.4%). The mean rates based on histological subtype were as follows: papillary thyroid cancer (PTC), 3.1% (range 0%-13.2%); micropapillary carcinoma (mPTC), 5.1% (range 0%-16.9%); and follicular thyroid cancer (FTC), 0.8% (range 0%-4.4%). In those patients who had preoperative imaging, mean malignancy rates were higher in patients with pre-identified nodules (19.8%) compared to those without any nodules (8.7%). Mean rates were lower in patients with GD/diffuse goitre (5.9%) compared to patients with TA (6.5%) and TMNG (12%).

CONCLUSION

Hyperthyroidism is associated with notable rates of thyroid cancer, although the mechanisms for this are not clear. The presence of nodules increases this risk. This review raises the question for considering preoperative assessment of nodules in all patients undergoing surgery for HT, in order to correctly assess and evaluate any patients with suspected concurrent thyroid malignancy, before proceeding with surgery.

PROGNOSIS OF DIFFERENTIATED THYROID CARCINOMA IN PATIENTS WITH GRAVES DISEASE: A SYSTEMATIC REVIEW AND META-ANALYSIS

Objective: It is still controversial whether differentiated thyroid carcinoma (DTC) in patients with Graves disease (GD) can be more aggressive than non-Graves DTC. We conducted a systematic review and meta-analysis to examine the association between GD and prognosis in patients with DTC. Methods: We comprehensively searched the databases of MEDLINE and EMBASE from inception to March 2019. We included published studies that compared the risk of mortality and prognosis between DTC patients with GD and those with non-GD. Data from each study were combined using the random-effects model. Results: Twenty-five studies from February 1988 to May 2018 were included (987 DTC patients with GD and 2,064 non-Graves DTC patients). The DTC patients with GD had a significantly higher risk of associated multifocality/multicentricity (odds ratio, 1.45; 95% confidence interval, 1.04 to 2.02; I², 6.5%; P = .381) and distant metastasis at the time of cancer diagnosis (odds ratio, 2.19; 95% confidence interval, 1.08 to 4.47; I², 0.0%; P = .497), but this was not associated with DTC-related mortality and recurrence/persistence during follow-up. Conclusion: Our meta-analysis demonstrates a statistically significant increased risk of multifocality/multicentricity and distant metastasis at the time of cancer diagnosis in DTC patients with GD than those without GD. Abbreviations: CI = confidence interval; DTC = differentiated thyroid carcinoma; GD = Graves disease; LN = lymph node; OR = odds ratio; PTC = papillary thyroid carcinoma; TC = thyroid carcinoma; TSAb = thyroid-stimulating antibody; TSH = thyroid-stimulating hormone.

Does hyperthyroidism worsen prognosis of thyroid carcinoma? A retrospective analysis on 2820 consecutive thyroidectomies

Background

Hyperthyroidism is associated with high incidence of thyroid carcinoma; furthermore, tumors arisen in hyperthyroid tissue show an aggressive behavior. Thyroid Stimulating Hormone (TSH) and Thyroid-stimulating antibodies, present in Graves’s disease, seem to play a key role in carcinogenesis and tumoral growth.

Methods

We retrospectively reviewed our series of patients who underwent thyroidectomy for thyroid carcinoma. We compared pathological features and surgical outcomes of hyperthyroid versus euthyroid patients.

Results

From 2007 to 2015, 909 thyroidectomies were performed at our institution for thyroid cancer: 87 patients were hyperthyroid and 822 euthyroid. We observed, in hyperthyroid patients, a higher rate of transient hypoparathyroidism (28.1% vs 13.2%; p < 0.01) and of node metastases (12.6% vs 6.1%; p = 0.03); also local recurrence rate was higher (5.7% vs 2.5%) even if not statistically significant (p = 0.17). Five-year disease free survival rate was significant lower in the same group (89.1% vs 96.6%; p = 0.03).

Conclusion

Thyroid cancers in hyperthyroid patients have an aggressive behavior, with high incidence of local invasion and a worse prognosis than euthyroid patients. All hyperthyroid patients should undergo a careful evaluation with ultrasound and scintigraphy; in case of suspicious nodules, an aggressive approach, including thyroidectomy and lymphectomy, is justified. In patients with toxic adenoma, thyroid cancer is uncommon, thus a loboisthmectomy can be safely performed.

Trial registration number

Research registry n. 2670 registered 19 June 2017 (retrospectively registered).

Concurrent hyperthyroidism and papillary thyroid cancer: a fortuitous and ambiguous case report from a resource-poor setting

Background

Concurrent thyroid cancer (TC) and hyperthyroidism (HT) is rare though increasingly being reported. HT due to TC is much rarer and more challenging especially in Africa where TC and HT have significant case fatality rates.

Case presentation

We present a 37-year-old Cameroonian female who had been on irregular regimens of propranolol and digoxin as treatment for worsening palpitations for 12 months. She came to our district hospital for her propranolol medication refill. We fortuitously identified features of HT and found a left uninodular goiter with no cervical lymphadenopathy. She was referred for thyroid assessment which suggested primary HT and an enlarged heterogeneous left lobe with a well-defined homogenous solid mass. We restarted her on propranolol and referred her for a course of methimazole. At the referral hospital, she also underwent a left thyroid lobectomy. The resected lobe was sent for histopathology which revealed a neoplastic nodule with features suggestive of a papillary thyroid cancer (PTC) causing HT. The patient’s clinical progress postoperatively was good and there was regression of hyperthyroid symptoms.

Conclusions

The historical, clinical, and laboratory findings were suggestive of HT due to PTC. A high index of suspicion, prompt referral and counter-referral lead to a positive outcome of such a rare case in a resource poor setting. We advocate for systematic and careful evaluation of all thyroid nodules.

[Panuveitis associated with papillary carcinoma of the thyroid]

Ocular involvement secondary to thyroid carcinomas is uncommon. Uveal metastasis may occur. More rarely, they can be responsible for paraneoplastic syndromes. We report the case of a 64-year-old woman who presented with a severe bilateral panuveitis with venous vasculitis associated with hyperthyroidism from a multinodular goiter, complicated by papillary carcinoma. Systemic steroid therapy was initiated; ocular symptoms resolved completely after total thyroidectomy. Other causes of panuveitis with venous vasculitis were ruled out. This is the first reported case of panuveitis associated with papillary thyroid carcinoma. The occurrence of the ocular symptoms with hyperthyroidism and their remission after surgery supports the possibility that this association may not be coincidental. A paraneoplastic phenomenon is suspected.

A solitary hyperfunctioning thyroid nodule harboring thyroid carcinoma: review of the literature

Hyperfunctioning nodules of the thyroid are thought to only rarely harbor thyroid cancer, and thus are infrequently biopsied. Here, we present the case of a patient with a hyperfunctioning thyroid nodule harboring thyroid carcinoma and, using MEDLINE literature searches, set out to determine the prevalence of and characteristics of malignant “hot” nodules as a group. Historical, biochemical and radiologic characteristics of the case subjects and their nodules were compared to those in cases of benign hyperfunctioning nodules. A literature review of surgical patients with solitary hyperfunctioning thyroid nodules managed by thyroid resection revealed an estimated 3.1% prevalence of malignancy. A separate literature search uncovered 76 cases of reported malignant hot thyroid nodules, besides the present case. Of these, 78% were female and mean age at time of diagnosis was 47 years. Mean nodule size was 4.13 ± 1.68 cm. Laboratory assessment revealed T₃ elevation in 76.5%, T₄ elevation in 51.9%, and subclinical hyperthyroidism in 13% of patients. Histological diagnosis was papillary thyroid carcinoma (PTC) in 57.1%, follicular thyroid carcinoma (FTC) in 36.4%, and Hurthle cell carcinoma in 7.8% of patients. Thus, hot thyroid nodules harbor a low but non-trivial rate of malignancy. Compared to individuals with benign hyperfunctioning thyroid nodules, those with malignant hyperfunctioning nodules are younger and more predominantly female. Also, FTC and Hurthle cell carcinoma are found more frequently in hot nodules than in general. We were unable to find any specific characteristics that could be used to distinguish between malignant and benign hot nodules.

Incidental Carcinoma in Multinodular Goiter: Risk Factors

The aim of the study was to analyze the frequency of incidental thyroid carcinoma (unknown tumor smaller than or equal to 10 mm) in a consecutive series of 462 total thyroidectomies for multinodular goiter and to investigate the clinical risk factors for this type of malignancy. A retrospective, single-center study of outcome data collected from patients with preoperative diagnosis of multinodular goiter who underwent total thyroidectomy at the General Surgery Unit of Pavia (Italy) between January 2000 and December 2008 was performed. Possible risk factors for malignancy were: gender, age, time of evolution of goiter, presence of a dominant nodule in multinodular goiter, hyperthyroidism, history of radiation to the neck, residence in an area of endemic goiter, prior thyroid surgery, calcifications in the goiter detected by neck ultrasound or chest X-rays, and a family history of thyroid diseases. In a 9-year period, 462 patients underwent total thyroidectomy. We found 41 cases of incidental thyroid carcinoma; the most common histopathological type was papillary. The multivariable analysis demonstrated that the clinical variables associated with occult carcinoma were a personal history of radiation therapy to the neck, the presence of calcifications detected by ultrasound or neck X-rays, and a family history of thyroid diseases; residence in an area of endemic goiter was a protective factor. A personal history of radiation to the neck, detection of calcifications by ultrasound or by neck X-rays, and a family history of thyroid diseases should be considered clinical risk factors for malignancy in multinodular goiter.

[Toxic intrathoracic goiter. Clinical profile and surgical morbidity in an endocrine surgery unit]

BACKGROUND

The development of postsurgical complications is exacerbated when several risk factors coincide in the same patient.

OBJECTIVE

To analyze the results of surgery for toxic intrathoracic goiter in terms of (a) the need for sternotomy; (b) morbidity and mortality; and (c) remission of compressive symptoms.

MATERIAL AND METHODS

A review (1980-2002) was carried out of 43 cases of toxic intrathoracic multinodular goiter according to Eschapase's definition (3 cm below the sternal manubrium) occurring in patients without previous thyroid surgery who underwent total thyroidectomy. There were 2 control groups: I (non-toxic intrathoracic goiter, without recurrence and not requiring total thyroidectomy) and II (non-intrathoracic, non-toxic goiter without recurrence, requiring total thyroidectomy). The following variables were analyzed: sociopersonal, clinical and surgical characteristics, morbidity, mortality, and outcome.

RESULTS

Compared with the control groups, the patient group had longer disease duration and was older. In 6 patients (14%) 1 was difficulty in intubation, and 2 patients required fiberoptic intubation. All goiters could be extirpated through the cervical route. The morbidity rate was 37% (n=16). Notably, 4 were recurrent lesions (9%), 1 of which was definitive, and 14 were hyperparathyroidism (33%), one of which was definitive. The only difference between the control groups and the patient group was a greater incidence of transitory hypoparathyroidism in the patient group than in control group II (33% versus 15%; p=0.0103). Surgical outcomes were excellent in terms of symptom remission.

CONCLUSIONS

In any unit with ample experience of endocrine surgery, total thyroidectomy in toxic intrathoracic goiter can be carried out with a low risk of postsurgical complications, a low incidence of sternotomies and complete symptom remission. In intrathoracic goiter surgery, the presence of associated hyperthyroidism does not increase postoperative morbidity.

Prognostic value of thyrotropin receptor antibodies (TRAb) in Graves' disease: a 120 months prospective study

In most trials, at least 30-60% of patients with Graves' disease treated with antithyroid drugs relapse within 2 years after therapy withdrawal. At present, there are no prognostic parameters available early in treatment to indicate patients likely to achieve long-term remission. Because thyrotropin receptor autoantibodies (TRAb) are specific for Graves' disease, we evaluated the ability of their levels and of their rate of change to predict long-term prognosis. In our study 216 consecutive patients with newly diagnosed Graves' disease started a therapy with methimazole. Patients were treated until they achieved euthyroidism and TRAb were measured at 6-month intervals throughout a follow up of 120 months. Our study demonstrated that at the onset of hyperthyroidism patients' age, sex, fT4 levels and goiter size had no prognostic value in predicting long-term prognosis (respectively p = 0.79; p = 0.98; p = 0.83; p = 0.89). On the contrary, at the time of diagnosis TRAb titer was a good predictor of the final outcome (p<0.001); a titer equal to (or) more than 46.5 UI/L could identify patients who had never achieved long-term remission with a sensitivity of 52% and a specificity of 78%. Also fall rate of TRAb at 6 months of follow up and after therapy withdrawal were useful to predict the final outcome (p<0.001). At 6 months of follow up the time of therapy withdrawal, a decrease of TRAb lower than 52.3% or even its increase could identify patients who had never achieved permanent remission with a sensitivity of 55% and a specificity of 79.1%. No single parameter among TRAb, satisfactory identified a sub-set of patients who achieved long remission. Accordingly to our data, the best result in predicting long term remission is probably given by the presence of at least one of the two features evaluated at 6 months (TRAb titer and/or percentage of TRAb fall rate), with a sensitivity of 63% and specificity of 88%. TRAb titers evaluated both at the onset of hyperthyroidism that at 6 months of therapy or their rate of fall at 6 months and at ATD withdrawal are predictors of outcome. However, the presence of at least one, between titers of TRAb or their rate of fall at six months, resulted to be the best predictor of remission with the higher sensitivity and specificity.

Incidental Thyroid Carcinoma in Thyrotoxic Patients Treated by Surgery

BACKGROUND AND AIMS

Thyroid malignancy detected incidentally in patients who are operated for thyrotoxicosis has been reported at different rates. The aim of this study was to investigate the rate of incidental thyroid carcinoma in thyrotoxic patients managed with surgery in our institution.

METHODS

Of the 375 thyrotoxic patients who had thyroid surgery between the years of 1997-2004, 70.7% were females and 29.3% were males. Among thyrotoxic patients 65.3% (n=245) had toxic multinodular goiter (TMG), 16.8% (n=63) had toxic adenoma (TA) and 17.9% (n=67) had Graves' disease.

RESULTS

Twenty-six (6.9%) of all thyrotoxic patients had thyroid carcinoma. Eighteen (7.3%) of TMG, 4 (6.3%) of TA and 4 (6%) of Graves' disease patients had thyroid carcinoma. Histologic examination revealed 18 papillary (9 microscopic), 5 follicular, 2 hurthle cell and 1 anaplastic carcinoma.

CONCLUSION

In our study, incidental thyroid carcinoma was found in 6.9% of subjects with thyrotoxicosis. Papillary thyroid microcarcinomas constituted 34.6% (26/9) of these newly diagnosed thyroid carcinomas. The incidence of thyroid carcinoma was not higher in subjects with Graves' disease compared to TMG and TA. The rate of incidental thyroid carcinoma in subjects with thyrotoxicosis treated with surgery was similar to previous studies reported from different countries.

The incidence of hyperthyroidism in patients with thyroid cancer in an area of iodine deficiency

BACKGROUND

The incidence of hyperthyroidism among thyroid malignancy varies greatly depending on the geographical area and iodine intake. The aim of the study was to evaluate the association of hyperthyroidism and thyroid cancer (TC) in an iodine deficient area.

PATIENTS AND METHODS

Medical records of 422 patients who underwent operation for TC between 1992 and 2000 in Ankara Oncology Hospital were reviewed. The characteristics of TC patients with hyperthyroidism were analyzed in respect to gender, age, histopathological type, thyroid function status, tumor size, extrathyroidal invasion, local recurrences, distant metastasis, AMES and MACIS scoring.

RESULTS

In the present patient series, among 422 patients with TC, hyperthyroidism was found in 12 patients (2.8%). None of the patients had Graves' disease. Of 12 patients with hyperthyroidism, 9 patients had papillary carcinoma, 1 patient had follicular carcinoma and 2 patients had follicular variant of papillary carcinoma. The tumor was in the active nodule in 5 patients.

CONCLUSION

The existence of hyperthyroidism among patients with differentiated TC is a clinical entity. Patients with hyperthyroidism and nodules require a careful approach in order to establish or exclude the possibility of TC especially in formerly iodine deficient areas.

Results of surgery for toxic multinodular goiter

PURPOSE

We analyzed the clinical and histological features of patients operated on for toxic multinodular goiter (TMG) to determine the clinical profile and evaluate the surgical results.

METHODS

We reviewed 672 patients who underwent surgery for multinodular goiter (MG), 112 (17%) of whom had hyperthyroidism, and analyzed the epidemiological, clinical, and surgical variables.

RESULTS

The patients with TMG tended to be older than those with nontoxic MG, with a greater evolution time of the goiter and a higher rate of positive antithyroid antibodies. In the multivariate analysis, the only feature characteristic of TMG, as opposed to nontoxic MG, was the evolution time. Morbidity was 34%, representative of the fact that that most of the patients were seen before the establishment of our endocrine surgical unit. The hyperthyroid symptoms resolved in all patients, but 4 of 17 patients who underwent partial surgical resection showed signs of relapse within a follow-up period of 98 +/- 71 months.

CONCLUSIONS

TMG is characterized by a long evolution time and is most effectively treated by total thyroidectomy, which achieves complete remission from symptoms, without relapse, and is necessary if there is associated carcinoma. However, the incidence of complications may be high if this procedure is not carried out by surgeons with experience in endocrine surgery.

Outcome of Patients Surgically Treated for Various Forms of Hyperthyroidism with Differentiated Thyroid Cancer: Experience at an Endocrine Center in Italy

PURPOSE

The incidence and aggressiveness of thyroid cancer associated with hyperthyroidism remains a subject of much controversy. The aim of this study was to analyze the frequency of coexisting hyperthyroidism and thyroid cancer, and to determine whether cancer becomes more aggressive with different forms of hyperthyroidism.

METHODS

We retrospectively studied 2,449 patients assessed for hyperthyroidism between 1985 and 2001. All patients with a "cold" nodule on scintigraphy, such as those with Graves' disease and a concomitant solid nodule, underwent fine-needle aspiration biopsy (FNAB). Criteria for surgery were cytological findings indicative of malignancy, goiter with signs of tracheal or esophageal compression, side effects of antithyroid drug therapy, or Graves' disease with multiple relapses after therapy withdrawal or responsiveness to antithyroid drugs.

RESULTS

Thyroid cancer was diagnosed more frequently in patients with Graves' disease (6.5%) than in those with uninodular toxic goiter (UTG) (4.4%) or multinodular toxic goiter (MTG) (3.9%). Lymph node involvement was found in 56% of the patients with Graves' disease, in 23% of those with MTG, and in none of those with UTG. Distant metastases were found in one patient with Graves' disease.

CONCLUSIONS

Cancers associated with Graves' disease seems to be more aggressive than those associated with MTG or UTG. Thus, we suggest that patients with Graves' disease be carefully monitored for the detection of thyroid nodules. Ultrasonography seems to be the best modality to detect such nodules.

Anaplastic thyroid carcinoma associated with Graves' disease

This report concerns a 79-year-old woman with coexisting anaplastic thyroid carcinoma (ATC) and Graves' disease (GD). The patient was referred to our clinic because of palpitation and a palpable mass on the left side of her neck. Thyroid function tests showed hyperthyroidism with elevated thyroid-stimulating antibodies. Ultrasonography of the thyroid demonstrated an adenomatous nodule-like marcated nodule (27.6 x 26.5 x 36.4 mm) with cystic degeneration inside the left lobe. (123)I thyroid scintigraphic imaging showed a cold area corresponding to the nodule with continuous uptake in the remaining thyroid tissue despite suppressed TSH levels. These findings led to a diagnosis of GD. On the other hand, the thyroid nodule could not be definitely diagnosed even after fine needle aspiration biopsy (FNAB) which produced findings suggestive of both papillary thyroid carcinoma and ATC. Open biopsy of the nodule showed an ATC. Regional lymph node metastases as well as multiple lung metastases, which could not be found at the initial visit, had been already developed by that time. Our case is pathophysiologically interesting because it suggests that GD or thyroid-stimulating antibodies (TSAb) may stimulate malignant transformation of differentiated carcinoma. It is also clinically important because it indicates that all thyroid nodules, particularly palpable cold nodules, associated with GD require careful management to detect malignancy because they are at higher risk of harboring malignancy.

Thyroid hormone and parathyroid hormone competing to maintain calcium levels in the presence of vitamin D deficiency

Weight loss and bone disease in the elderly are very often attributed to malignancy. Rarely, benign treatable conditions may be overlooked. Thyrotoxicosis, a benign treatable condition, needs to be excluded in such patients. The diagnosis may be delayed, since the symptoms are often subtle, and secondary complications including bone disease (osteoporosis) are therefore more frequent at the time of presentation. The case presented here illustrates this well, and also highlights the value of measuring vitamin D levels in such patients. The most interesting aspect of this case was the reciprocal relationship between thyroxine and parathyroid hormone observed in maintaining calcium homeostasis in this thyrotoxic patient with low vitamin D levels.

Thyroid nodular lesion: analysis of cancer risk based on Kuma Hospital experience

It is a difficult question, whether it is malignant or not, when you follow up patients with thyroid nodular lesions. Cytological examination helps to solve this issue more accurately but a cancer risk still exists in patients with a negative cytology, non-diagnostic or suspicious follicular neoplasms. Analysis of cancer risk in patients with benign thyroid nodular lesions was carried out among 1044 cases who underwent thyroid surgery at Kuma Hospital, Kobe, Japan, in 2000. The purpose of this study was to provide evidence of cancer risk in those patients in Japan. Among the 356 cases with benign nodular lesions, 99 cases of papillary carcinoma were found in the thyroid parenchyma. Seventy-nine of the 99 cases were clinical cancer and were found preoperatively by cytology, while 20 out of 277 (7.22%) cases were found postoperatively as incidental carcinoma. The incidence of follicular carcinoma of a minimally invasive type in the index nodule was 22 out of 279 (7.89%) cases in patients who were surgically treated.

Prevalence of thyroid cancer in Graves' disease: a retrospective study of a cohort of 103 patients treated surgically

BACKGROUND: Thyroid nodules in patients with Graves' disease (GD) are common, and the incidence of coexisting thyroid carcinoma is a much debated subject, which is addressed in this study. METHODS: In order to determine the incidence rate of coexisting malignancy, a retrospective study was conducted on 103 patients who underwent surgery for GD between 1990 and 2000 at the Cliniques Universitaires Saint-Luc in Brussels, Belgium. The patients were classified into groups. Those in group I had a solitary palpable nodule (4.9%), those in group II multiple palpable nodules (12.6%), group IIIa had nodule(s) revealed by imaging techniques (incidentalomas: 17.5%), and group IIIb had diffuse non-nodular goiter (65%). RESULTS: Patients with nodules (groups I, II, and IIIa) were found to have significantly more thyroid carcinomas than those with diffuse non-nodular goiters (P=0.02), and the rate of malignancy was significantly increased when the nodules were palpable (groups I and II; P=0.03). Eight patients (7.8%) were diagnosed as having coexisting carcinomas, all but one being microcarcinomas. CONCLUSIONS: Well-differentiated papillary carcinomas are found to coexist with GD surgically treated (7.8%) and occur most frequently in GD with palpable nodular lesions (35%). Even though the majority (88%) of coexisting carcinomas are microcarcinomas, the presence of palpable nodules justifies further evaluation and follow-up.

Prevalence of thyroid cancer in hyperthyroidism treated by surgery

The reported prevalence of thyroid cancer with concurrent hyperthyroidism varies from 0.21% to 9.0%. This variability may be due to multiple factors, such as indications for surgery and histopathologic accuracy. However, this condition is not rare and its prevalence has increased in recent surveys, perhaps as a result of more detailed examinations. The aim of this retrospective study was to determine the prevalence of thyroid cancer in hyperthyroid patients at surgery. Forty-five patients, 34 women and 11 men, underwent surgery for hyperthyroidism in our department between 1989 and 2000. Ages ranged from 14 to 67 years. There were 42 cases of Graves' disease, one of functional multinodular goiter, and two of single toxic nodules. Forty-three patients underwent total thyroidectomy and two underwent total lobectomy. Six cases (13.3%) of thyroid cancer were found, two men and four women with ages ranging from 19 to 48 years. Final histologic examination revealed three papillary carcinomas, one follicular carcinoma, one follicular carcinoma combined with clear-cell carcinoma, and one clear-cell carcinoma. Thus, in our department, the prevalence of thyroid cancer in hyperthyroidism treated using surgery was 13.3%. Our study showed that even a single toxic nodule may occur with concurrent thyroid cancer. Careful evaluation of such patients is needed to exclude the presence of associated malignancy and to determine the most appropriate therapeutic plan.