Metastatic pure papillary thyroid carcinoma presenting as a toxic hot nodule

Malignancy risk of hyperfunctioning thyroid nodules compared with non-toxic nodules: systematic review and a meta-analysis

Background

Hyperfunctioning or hot nodules are thought to be rarely malignant. As such, current guidelines recommend that hot nodules be excluded from further malignancy risk stratification. The objective of this systematic review and meta-analysis is to compare the malignancy risk in hot nodules and non-toxic nodules in observational studies.

Methods

Ovid MEDLINE Daily and Ovid MEDLINE, EMBASE, Scopus, and Web of Science databases were searched. Observational studies which met all of the following were included: (1) use thyroid scintigraphy for nodule assessment, (2) inclusion of both hyperfunctioning and non-functioning nodules based on scintigraphy, (3) available postoperative histopathologic nodule results, (4) published up to November 12, 2020 in either English or French. The following data was extracted: malignancy outcomes include malignancy rate, mapping of the carcinoma within the hot nodule, inclusion of microcarcinomas, and presence of gene mutations.

Results

Among the seven included studies, overall incidence of malignancy in all hot thyroid nodules ranged from 5 to 100% in comparison with non-toxic nodules, 3.8–46%. Odds of malignancy were also compared between hot and non-toxic thyroid nodules, separated into solitary nodules, multiple nodules and combination of the two. Pooled odds ratio (OR) of solitary thyroid nodules revealed a single hot nodule OR of 0.38 (95% confidence interval (CI) 0.25, 0.59), toxic multinodular goiter OR of 0.51 (95% CI 0.34, 0.75), and a combined hot nodule OR of 0.45 (95% CI 0.31, 0.65). The odds of malignancy are reduced by 55% in hot nodules; however, the incidence was not zero.

Conclusions

Odds of malignancy of hot nodules is reduced compared with non-toxic nodules; however, the incidence of malignancy reported in hot nodules was higher than expected. These findings highlight the need for further studies into the malignancy risk of hot nodules.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13044-021-00094-1.

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.

Preoperative Tc-99m-pertechnetate scan visualization of gross neck metastases from microcarcinoma papillare and another papillary carcinoma of tall cell variant scintigraphically presented like small warm nodule in Graves disease patient

PURPOSE

Preoperative scintigraphic visualization of metastases from well-differentiated thyroid microcarcinoma in patients with Graves disease is extremely rare, as is the scintigraphic visualization of poorly differentiated thyroid carcinoma as a warm nodule. We present a patient with Graves disease and both of these rare entities.

CASE REPORT

A 47-year-old woman complained of a growing left-side neck mass and symptoms of thyrotoxicosis. On clinical examination, the thyroid was palpable without discernible nodularity, while the left side of the neck was occupied by 3 gross, painless nodules. She also had signs of thyrotoxicosis and biochemical parameters of Graves hyperthyroidism. Ultrasound examination showed moderately hypoechogenic thyroid with a small hypoechogenic nodule in the upper pole of the left lobe and 3 gross, almost normoechogenic nodules on the left side of the neck. On Tc-99m-pertechnetate pinhole scintigraphy there was a small, warm nodule in the upper pole of the left lobe and 3 gross metastatic nodules on the left side of the neck. Fine needle aspiration of the neck nodules was consistent with metastases from thyroid papillary carcinoma. After thyrostatic preparation a total thyroidectomy with left modified radical neck dissection was done.

RESULTS AND CONCLUSION

Histopathologic examination disclosed 2 carcinomas in the left thyroid lobe. One of them was a tall cell variant of papillary carcinoma in the upper pole of the left lobe that measured 5 mm and corresponded to the small warm nodule, and the second one was a classic form of papillary microcarcinoma that measured 2 mm. Metastases accrued from the classic form of papillary microcarcinoma. Although the patient had 2 thyroid carcinomas, one with metastases and the other of more aggressive form, which is consistent with advanced stage and aggressiveness, she is now disease-free, 4 years after the operation and radioiodine ablation.

Risk factors for well-differentiated thyroid carcinoma in patients with thyroid nodular disease

OBJECTIVES

Evaluate current accepted risk factors for well-differentiated thyroid carcinoma, and develop a predictive model to determine one's risk of malignancy given a thyroid nodule.

STUDY DESIGN

Retrospective analysis of 600 patients.

SUBJECTS AND METHODS

Patients with benign thyroid nodular disease and with well-differentiated thyroid cancer were randomly selected. Patient, clinical, and investigational data were compared by means of univariate and multivariate regression analyses.

RESULTS

Age, regional lymphadenopathy, ipsilateral vocal cord palsy, solid and/or calcified nodules, and an aspiration biopsy being malignant or suspicious predicted for cancer (P < 0.05). Regional lymphadenopathy and vocal cord palsy are perfect predictors of malignancy. Multivariate analysis indicated age, solid and/or calcified nodules, and all fine-needle aspiration biopsy results to be significant in assessing risk (P < 0.05).

CONCLUSION

Taking individual risk factors in isolation is not always reliable. Using a predictive model, one can anticipate a patient's risk of malignancy when the diagnosis is unclear.

Does a Leu 512 Arg thyrotropin receptor mutation cause an autonomously functioning papillary carcinoma?

In the last decade, studies were first done to determine the frequency of Gsalpha and later thyrotropin receptor (TSHR) mutations in benign autonomously functioning thyroid nodules (AFTN). Different frequencies ranging from 0% to 38% for GSp mutations and from 20% to 86% for TSHR mutations were found. There were only some limited case reports related to TSHR genetic alterations in malignant AFTN. Their role in autonomously functioning thyroid carcinomas is not well established. We present a patient who had thyroidectomy for toxic multinodular goiter and a papillary carcinoma was demonstrated histopathologically. Genomic DNA was isolated from two solid areas in the hot nodule and peripheral leukocytes of the patient. After amplifying the related regions, TSHR and GSalpha genes were analyzed by single-strand conformation polymorphism (SSCP) analysis. The precise localization of the mutations was identified by automatic DNA sequence analysis. An activating mutation of the TSHR gene (Leu 512 Arg) was found in the autonomously functioning papillary carcinoma. It is believed that this mutation causes constitutive activation of the cyclic adenosine monophosphate (cAMP) signal transduction pathway and thereby causes thyrotoxicosis and a hot thyroid nodule in an autonomously functioning papillary carcinoma.

Is it useful to routinely biopsy hot nodules in iodine deficient areas?

Incidence of nodular thyroid disease as well as that of functioning thyroid nodules (FTN) increases dramatically in iodine deficient (ID) areas. Cancer is extremely rare in FTN; thus, some do not routinely biopsy and treat them with radioactive iodine (RAI) straight away or follow-up. The outcome of 296 patients followed or treated at our institution for solitary or multiple FTN were retrospectively evaluated. Hospital records of 224 female, 72 male patients, with a mean +/- SD age of 54.9 +/- 12.4 yr and followed for 22 (0-156) months were examined. 175 patients had solitary, 121 had multiple hot or warm nodules. 230 (77.7%) of the patients received RAI treatment. 402 fine needle aspiration biopsies (FNABs) were performed on 260 patients and on 343 FTN (381 benign and 21 suspicious diagnoses). Eleven of the patients were operated for suspicious FNAB results and 10 were followed-up. Only one nodule turned out to be malignant. Malignancy is extremely rare in functioning thyroid nodules (0.34%) and some of malignant cases could be predicted by their suspicious clinical features. Routine practice of treating FTN with RAI therapy is reasonable in clinically low-risk patients. FNAB is reserved for cases with suspicious clinical features, resulting in fewer surgeries and reduced cost.

A patient with two thyroid papillary carcinomas demonstrating hot and cold lesions on 113I thyroid scintigraphy

A 44-year-old euthyroid woman had two palpable nodules in the thyroid gland. 123I thyroid scintigraphy showed a hot nodule in the right lobe and a cold one in the left lobe. Total thyroidectomy was performed, and histopathologic examination revealed that both tumors contained papillary carcinoma. Thus, hot nodules on a thyroid scintigram with 123I do not necessarily preclude malignancy.

Differentiated thyroid carcinoma with functional autonomy

OBJECTIVE

To present a case of papillary carcinoma in an autonomously hyperfunctioning thyroid nodule.

METHODS

We chronicle the clinical and laboratory findings in a patient with a painless neck mass, with a particular focus on the pathologic findings after surgical removal of the right thyroid lobe.

RESULTS

A 39-year-old woman had an enlarging nodule of the right thyroid lobe. Results of thyroid function tests suggested subclinical hyperthyroidism. Two months later, the patient complained of increasing swelling in the neck (but still had no symptoms suggestive of hyperthyroidism). Thus, resection of the right thyroid lobe was performed. Pathologic analysis disclosed low-grade papillary thyroid carcinoma within the nodule, with a small rim of compressed inactive-appearing thyroid tissue surrounding the nodule. Subsequently, she underwent total thyroidectomy and follow-up care for thyroid carcinoma.

CONCLUSION

Although solitary hyperfunctioning nodules of the thyroid gland are usually considered benign, the current case suggests that the diagnosis of autonomous thyroid nodules does not preclude thyroid carcinoma in a functioning nodule.

A Phe 486 thyrotropin receptor mutation in an autonomously functioning follicular carcinoma that was causing hyperthyroidism

Hot nodules are rarely found to be carcinomas. We report a case of a nonmetastatic follicular carcinoma that presented as a hot nodule that was causing hyperthyroidism. A base substitution (ATC for TTC) was found in codon 486 of the TSH receptor gene and this resulted in the substitution of an isoleucine for a phenylalanine in the first extracellular loop of the receptor. This was absent in the deoxyribonucleic acid from the surrounding normal thyroid tissue indicating its somatic origin. This mutation, which was previously reported to activate both cyclic adenosine monophosphate and the inositol phosphate-diacylglycerol cascades, may have been responsible for the constitutive activation of the thyrotropin receptor and resulting hyperfunction of this follicular carcinoma.

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

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