Plummer's disease: localized thyroid autonomy

Clinical Characteristics and Predictors Related to the Progression of Multinodular Goiter Causing Tracheal Compression and Deviation: A Report of Two Cases and Review of the Literature

We describe the clinical course of two patients who developed tracheal compression and deviation by multinodular goiter (MNG). Case 1: A 66-year-old woman presented with thyroid swelling. Five years after the initial admission, she was diagnosed with hyperthyroidism by Graves' disease and increased bilateral thyroid lobes compressing the trachea. Thyroglobulin was elevated from 210 to 472 ng/mL. Case 2: A 52-year-old woman presented with thyroid swelling. Five years after the initial admission, the increased right lobe deviated the trachea and compressed the right recurrent laryngeal nerve. Thyroglobulin was elevated from 122 to 392 ng/mL. Two cases and literature review indicated that MNG with >50 mm, solid components, and extension to the mediastinum or paralarynx were risk factors of tracheal compression and deviation. Monitoring thyroglobulin elevation can help predict the clinical course.

Radioiodine therapy of thyroid autonomy

Radioiodine therapy (RIT) of thyroid functional autonomy (TFA) is rapidly evolving, though it has been recognized for decades as a very effective treatment of toxic nodular varieties. Indeed, TFA is a frequent cause of persistent subclinical hyperthyroidism, which should be regarded as a new metabolic syndrome, with well-established adverse cardio-vascular consequences. Sensitive TSH assays and multiparametric ultrasounds are not accurate enough to reliably diagnose TFA and identify its main variants, unifocal, multifocal (UFA/MFA) and disseminated autonomy (DISA). Modern diagnostic tools are extensively presented and rely upon Thyroid Scan imaging and quantification. A new relationship allows predicting at baseline, an excess of 123I uptake as compared to the TSH stimulation in compensated TFA. Suppressed TS are useful with either isotope, otherwise. Diagnosis of the DISA variant is presented as compared to Graves' disease. Dosimetry has some specificity in TFA work-up. Indeed, the spatial distribution of the dose is as important as the mean value itself and can be eventually controlled by adjusting the TSH level with the smart use of LT3 or antithyroid drug therapy (ATD). A review of the different ways to determine the target mass from anatomical to functional approaches is presented. Main clinical and dosimetric published results of RIT are summarized according to clinical goals. Endogenous TSH stimulation using an ATD preparation has promising results in reducing big autonomously functioning goiters. Finally, we report preliminary successful results of preventive RIT using short term LT3 suppression in compensated TFA, with low administered activities and low rate of hypothyroidism.

Effectiveness of percutaneous ethanol injection therapy in benign nodular and cystic thyroid diseases: long-term follow-up experience

This study was designed to clarify the long-term efficacy and safety of percutaneous ethanol injection (PEI) therapy in benign nodular and cystic thyroid diseases, and to evaluate response by criteria defined as disappearance of hot nodule. Solid nodule and complex cyst were classified into three groups in accordance with volume reduction. In autonomously functioning thyroid nodule (AFTN), disappearance of hot nodule with normalization of thyroid hormone level and restored extra-nodular uptake was defined to be curative. In solid nodule (n = 198) and complex cyst (n = 432), initial volume was significantly reduced to post-PEI and final volumes, and volume reduction persisted during follow-up period. Complete response, partial response and no response were as follows: 17.2%, 71.7%, 11.1% in solid nodule; 19.0%, 60.4%, 20.6% in complex cyst, respectively. Differences of volume reduction according to initial volume (> or =10 mL vs. <10 mL) were significant. Correlations between initial and final volumes, and between initial volume and volume reduction were also significant. In 24 patients with AFTN, when effectiveness was assessed by disappearance of hot nodule, only 1 case was curative. Reexpansion or recurrence was observed in 5 cases. Complications developed in 9.0% but there was no permanent or serious complication in this study. In conclusion, our data suggest that PEI therapy could be an effective and safe therapeutic modality for benign nodular and cystic thyroid diseases especially when initial volume is more than 10 mL, but may not induce disappearance of hot nodule itself in AFTN.

Percutaneous ethanol injection treatment in benign thyroid lesions: role and efficacy

GOAL

To establish the role of percutaneous ethanol injection (PEI) treatment in benign thyroid lesions by evaluating: (1) the long-term efficacy and side effects of the treatment, (2) the factors predictive of efficacy of PEI, and (3) the cost effectiveness of the procedure.

MATERIALS AND METHODS

Fifty-eight recurrent cystic nodules, 95 autonomously functioning nodules (AFTN), and 17 hyperfunctioning nodules causing thyrotoxicosis (toxic nodules) were treated by PEI from 1990 to 1996 in our center. Ultrasound (US) and color flow doppler (CFD) examinations were carried out before and after each treatment. In patients with AFTN, serum thyrotropin (TSH), free triiodothyronine (FT3), free thyroxine (FT4), thyroid peroxidase antibody (TPOAb) levels were tested before and after PEI. All patients were independently reexamined by two external reviewers after a minimum follow-up of 5 years (median, 6.9 years).

RESULTS

The median number of treatments was 2.0 (range, 1.0-4.0) for cystic nodules, 4 (range, 2.0-6.0) for AFTN, and 5 (range, 3.0-7.0) for toxic nodules. At the 5-year evaluation cystic nodules showed a volume reduction greater than 75% versus baseline in 86.2% of cases and an improvement of local symptoms in 91.4% of cases. AFTN presented serum TSH within normal limits in 60.0% of patients. Toxic nodules showed a detectable serum TSH and normal FT3 and FT4 values in 35.3% of cases. Two cases of transient dysphonia were observed. In cystic lesions no significant correlation was found between the baseline and the final volume (r2 = 0.17) and no significant predictor of treatment efficacy was found. However, unilocularity was associated with a lower number of treatments than multilocularity (median, 2.0 vs. 3.0). Independent predictors of clinical efficacy in both AFTN and toxic nodules were a baseline volume less than 5.0 mL and a fluid component greater than 30% (odds ratio [OR] = 6.1 and 3.3, respectively).

CONCLUSIONS

Most recurrent cystic lesions of the thyroid can be cured by PEI, which should become the first line of treatment. The majority of AFTN and toxic nodules with volume less than 5.0 mL presented a marked volume decrease and normal serum TSH levels when treated by PEI, which seems a valid alternative to clinical follow-up alone in patients refusing 131I. PEI is not indicated in large or toxic nodules, for which 131I is the treatment of choice.

Management of simple nodular goiter: current status and future perspectives

The simple nodular goiter, the etiology of which is multifactorial, encompasses the spectrum from the incidental asymptomatic small solitary nodule to the large intrathoracic goiter, causing pressure symptoms as well as cosmetic complaints. Its management is still the cause of considerable controversy. The mainstay in the diagnostic evaluation is related to functional and morphological characterization with serum TSH and (some kind of) imaging. Because malignancy is just as common in patients with a multinodular goiter as patients with a solitary nodule, we support the increasing use of fine-needle aspiration biopsy (cytology). Most patients need no treatment after malignancy is ruled out. In case of cosmetic or pressure symptoms, the choice in multinodular goiter stands between surgery, which is still the first choice, and radioiodine if uptake is adequate. In addition to surgery, the solitary nodule, whether hot or cold, can be treated with percutaneous ethanol injection therapy. If hot, radioiodine is the therapy of choice. Randomized studies are scarce, and the side effects of nonsurgical therapy are coming into focus. Therefore, the use of the optimum option in the individual patient cannot at present be based on evidence. However, we are of the view that levothyroxine, although widely used, should no longer be recommended routinely for this condition. Within a few years, the introduction of recombinant human TSH and laser therapy may profoundly alter the nonsurgical treatment of simple nodular goiter.

Activating thyrotropin receptor mutations in histologically heterogeneous hyperfunctioning nodules of multinodular goiter

Activating thyrotropin (TSH) receptor mutations have been found in toxic adenomas and in hot nodules contained in toxic multinodular goiter. The typical feature of multinodular goiter is the heterogeneity in morphology and function of different follicles within the same enlarged gland. In this report we describe a patient with a huge multinodular goiter, normal free triiodothyronine (FT3) and free thyroxine (FT4) serum values, and subnormal TSH serum concentration. Thyroid scintiscan showed two hot areas corresponding to the basal and apical nodules of the left lobe. The right lobe was poorly visualized by the radioisotope. The patient underwent thyroidectomy, and histological examination of the tissue was performed. Genomic DNA was extracted from the tissue specimen and direct sequencing of the TSH receptor and Gs alpha genes was done. At histology, one hyperfunctioning nodule had the typical microscopic structure of thyroid adenomas, and the other contained multiple macrofollicular areas not confined by a capsule. In spite of this histological difference, both hyperfunctioning nodules harbored a mutation of the thyrotropin receptor (TSHr) gene: an isoleucine instead of a threonine in position 632 (T632I) in the first nodule and a methionine instead of an isoleucine in position 486 (I486M) in the second nodule. In conclusion, our findings show for the first time that gain-of-function TSHr mutations are not only present in hyperfunctioning thyroid nodules with the histological features of the true thyroid adenomas, but also in hyperfunctioning hyperplastic nodules contained in the same multinodular goiter.

Hyperfunctioning differentiated thyroid carcinoma

A case of functioning plurifocal papillary carcinoma causing a clinical condition of hyperthyroidism is presented. Histologically, the carcinoma presented a dominant macrofocal nodule of an approximately 5 cm diameter, surrounded by chronic thyroiditis. Its occurrence in a patient under 20 years of age within a hot area in the thyroid bed and the lack of histological findings of hyperplastic tissue led the authors to consider this a rare case of hyperfunctioning differentiated thyroid carcinoma, and not a pure association of hyperthyroidism and carcinoma. Autonomously functioning thyroid nodules that are differentiated carcinomas are extremely rare with only 18 such cases reported in literature. While in the past it was commonly believed that a hot nodule is unlikely to be malignant, the possibility of an hyperfunctioning carcinoma should not be overlooked.

Iodine-induced hyperthyroidism: occurrence and epidemiology

We have critically reviewed the available information on iodine-induced hyperthyroidism (IIH) from published sources and other reports as well as the experience of the authors in Tasmania, Zaire, Zimbabwe, and Brazil. Administration of iodine in almost any chemical form may induce an episode of thyrotoxicosis (IIH). This has been observed in epidemic incidence in several countries when iodine has been given as prophylaxis in a variety of vehicles, but the attack rate as recorded has been low. IIH is most commonly encountered in older persons with long standing nodular goiter and in regions of chronic iodine deficiency, but instances in the young have been recorded. It customarily occurs after an incremental rise in mean iodine intake in the course of programs for the prevention of iodine deficiency, or when iodine-containing drugs such as radiocontrast media or amiodarone are administered. The biological basis for IIH appears most often to be mutational events in thyroid cells that lead to autonomy of function. When the mass of cells with such an event becomes sufficient and iodine supply is increased, the subject may become thyrotoxic. These changes may occur in localized foci within the gland or in the process of nodule formation. IIH may also occur with an increase in iodine intake in those whose hyperthyroidism (Graves' disease) is not expressed because of iodine deficiency. The risks of IIH are principally to the elderly who may have heart disease, and to those who live in regions where there is limited access to medical care. More information is needed on the long-term health impact of IIH or "subclinical" IIH, especially in the course of prophylaxis programs with iodized salt or iodinated oil in regions where access to health care is limited.

Magnetic resonance evaluation of autonomous thyroid nodules treated by percutaneous ethanol injection

Magnetic resonance (MR) imaging was used to evaluate the effect of ultrasound-guided percutaneous ethanol injection (PEI) of autonomous thyroid nodules (ATNs). Nine patients affected with ATN (3.7-32.2 mL volume) underwent PEI (4-19 mL ethanol, subdivided in 3-6 weekly procedures). MR imaging (1.5 T) was performed before each alcoholization and 1 month after the last PEI procedure with the following parameters: T1- (550/12) and T2-weighted (2200/160) spin-echo images; 4-mm slices, 10% gap; coronal planes. A further seven patients with normal thyroid function, who had undergone PEI 6-18 months before, underwent an MR examination with the same parameters. The signal-to-noise ratio (S/N) of ATN and extranodular gland, as well as ATN volume, were evaluated on the T2-weighted images. On T1-weighted images, ATNs appeared mostly hypointense before treatment, with hyperintense areas during treatment, and were lightly hyperintense 6-18 months after treatment. S/N on T2-weighted images: extranodular gland 3.5-9.2; ATNs, before treatment 13.2-19.7, before the last procedure 7.7-11.6, 1 month after the last procedure 5.6-10.9; previously treated ATNs, 4.3-8.2. No significant volume reduction was observed with MR 1 month after the last procedure. The MR examination time was about 15 minutes. In conclusion, the effect of PEI on ATNs can be evaluated with an MR examination that is not very time consuming.

Percutaneous ethanol injection therapy for autonomously functioning thyroid nodule

Four patients with solitary autonomously functioning thyroid nodule (AFTN; 2 toxic and 2 subclinically toxic) received ultrasonography (US)-guided percutaneous ethanol injection therapy (PEIT). The pretreatment scintigraphic appearance of the nodule was hot, and radioactivity in the extranodular tissue was completely suppressed throughout. Ninety-nine percent ethanol was slowly injected under US guidance. As a rule, the injection was performed in fractionated sessions and the treatment was repeated until the total amount of ethanol exceeded the baseline nodular volume. The therapy was successful. Complete remission of hyperthyroidism was observed among the patients with toxic nodule. The basal level of TSH and its response to TRH injection was normalized in the patients with subclinically toxic nodule. Posttreatment scintigrams revealed that the extranodular tissue recovered and radioactivity in the hot nodule had noticeably decreased. The rate of reduction in the nodular volume was more than 80% in all. There was no recurrence or development of hypothyroidism during a follow up of 10 to 23 months. The main side effect was mild and transient pain and/or a burning sensation at injection. No severe or permanent complications occurred. Although the number of our cases was small, the results suggest that PEIT is a useful program in treating AFTN.

Percutaneous intranodular ethanol injection: a new treatment for autonomous thyroid adenoma

Established methods for definitive ablation of autonomous thyroid nodules are surgery and radioiodine. Since it has been demonstrated that percutaneous ethanol injection can inactivate parathyroid adenomas and small hepatocellular carcinomas, we started a trial of this treatment in patients with autonomous thyroid nodules. Twenty-eight patients, 22 toxic and 6 nontoxic, all with undetectable thyrotropin serum levels and suppressed extranodular tissue on scintigraphy, were treated. Treatment consisted of percutaneous intranodular ethanol injection under ultrasound guidance. The total amount of alcohol injected ranged from 0.4 to 2.2 times the estimated nodule volume, divided into 4 to 9 injections performed at 2 to 7 day intervals. Most patients were treated with a single cycle of injections, but 7 of them required 2 cycles. The signs and symptoms of hyperthyroidism disappeared in all cases. Apparently complete cure (normal serum free thyroid hormones, thyrotropin in basal conditions and after thyrotropin releasing hormone, reactivation of extranodular tissue on scintigraphy with nodule no longer visible) was obtained in 17 patients (13 after 1 cycle and 4 after 2 cycles). Partial cure (normal serum free thyroid hormone levels, detectable thyrotropin levels with normal or blunted response to thyrotropin releasing hormone and partial reactivation of extranodular tissue on scintigraphy with nodule or parts of it still visible) was obtained in 10 patients (8 after 1 cycle and 2 after 2 cycles). In 1 patient with a very large nodule thyrotropin levels remained undetectable, but thyroid hormone levels eventually became normal. No recurrences were observed after a follow-up of 12 to 32 months (mean 20 months). No serious side effects were encountered. A clinically valuable result was obtained in all patients. These data suggest that this form of treatment could constitute an alternative to surgery and radioiodine for the ablation of autonomous thyroid nodules.

Cytofluorometric analysis of lymphocyte subsets in thyroid aspirates from patients with autonomously functioning nodules

A microscale method, based on two-colour dye immunolabelling and flow sorting cytofluorometry, was used to characterize lymphocyte subsets in thyroid tissue specimens obtained by fine-needle aspiration (FNA) in 21 patients with autonomously functioning thyroid nodule (AFTN) and five patients with cold thyroid nodule (CTN). Inversion of the ratio between CD4+ and CD8+ lymphocytes, due to a relative increase of CD8+ cells, was found among intrathyroidal lymphocytes in AFTN patients. The abnormal lymphocyte subset distribution was not observed in the peripheral blood of the same group of patients. In patients with CTN the lymphocyte subset distribution was normal, both in the thyroid and in the peripheral blood. In AFTN patients, a significant correlation was observed between the decrease of intrathyroidal CD4+/CD8+ ratio and the increase of plasma thyroid hormone levels. Whether the immunological abnormalities found in AFTN could play a pathogenetic role in the clinical presentation and outcome of the disease remains to be established. The FNA-applied micromethod used in this study could be extended as a routine investigation to characterize the immunogenic substrate of thyroid disorders.