Fractionated radioiodine therapy for hyperthyroidism caused by widespread metastatic follicular thyroid carcinoma

Case report: A case of hyperthyroidism secondary to bone metastasis of differentiated thyroid cancer

It is usually believed that differentiated thyroid cancer is less likely to have distant metastases and rarely occurs secondary to hyperthyroidism. In our case report, we describe a patient diagnosed with thyroid fetal adenoma in 2002 who subsequently presented with a painful lump in her right rib. Through puncture biopsy, the mass was considered as metastatic follicular thyroid carcinoma, and then she appeared to have hyperthyroidism. The results of SPECT examination and other tests suggested that the hyperthyroidism was secondary to the thyroid cancer. The patient further underwent total thyroidectomy, and the pathology did not find any follicular thyroid foci. In this article, we analyze and discuss this case and review the relevant literature.

Treatment and outcome of patients with Graves' disease and metastatic differentiated thyroid cancer

BACKGROUND

The aim of the study was to report on the experience in a single tertiary cancer center about the treatment and outcome of patients with Graves' disease (GD) and metastatic thyroid cancer as compared with patients without GD in our country.

PATIENTS AND METHODS

Altogether, 28 patients (8 males, 20 females; 49-85 years of age; median 74 years) were treated because of differentiated thyroid cancer and distant metastasis at the time of diagnosis during a 10-year period (from 2010 to 2019) in the Republic of Slovenia. The subject of our retrospective study were four patients (three men, one female; 64-76 years of age, median 73 years) who had Graves' disease and metastatic thyroid cancer.

RESULTS

The mean age of patients without GD and with GD was 74 years and 71 years, respectively (p = 0.36). There was a trend for male predominance in patients with GD (p = 0.06). There was no statistical difference in size of primary tumors, pT stage or pN stage between the group of patients without GD and with GD. The median length of follow-up was 3.33 years (range 0.04-7.83) and 5-year disease-specific survival was 51%. One of four patients with GD and 14 of 24 patients without GD died of thyroid cancer. There was no statistical difference in disease-specific survival between patients' group of without GD and with GD (p = 0.59).

CONCLUSIONS

In our country Slovenia, 14% of patients with metastatic differentiated thyroid carcinoma at the time of diagnosis had Graves' disease. There was no difference in the treatment, outcome or survival of patients with GD in comparison to those without GD.

Long-Term Disproportional TSH Hyposecretion in a Patient With Nonautoimmune Hyperthyroidism After Radioiodine Therapy

Nonautoimmune hyperthyroidism (NAH), caused by constitutively active mutants of the thyrotropin receptor (TSHR) gene, is recommended to be treated with total thyroidectomy followed by radioiodine administration. Herein, we present a 39-year-old woman with sporadic NAH caused by a TSHR-L512Q mutation. At the age of 20 years, she presented with a large goiter of 370 mL, treated with thiamazole, and opted for radioiodine therapy as outpatient management. Over the next 17 years, she underwent 6 treatments of 13 mCi radioiodine each. She did not experience a relapse of hyperthyroidism, and thiamazole was reduced and later withdrawn during the final radioiodine treatment. The patient's goiter significantly reduced to 18 mL, and thyroid function tests showed that free thyroxine and free triiodothyronine levels were below the lower limit of the reference ranges, while TSH remained within the reference range for 20 months. Along with an almost normal TSH response to thyrotropin-releasing hormone stimulation, no pituitary atrophy was observed on magnetic resonance imaging. Contrary to the recommended treatment, this case showed that fractionated radioiodine therapy alone is effective in controlling thyroid function and in reducing goiter size. Low TSH levels during treatment should not be assessed as subclinical hyperthyroidism or as risk of relapse.

Hyperfunctioning thyroid carcinoma: A systematic review

Hyperthyroidism may be caused by the development of primary or metastatic thyroid carcinoma. The aim of the present study was to collect recently reported cases of hyperfunctioning thyroid carcinoma in order to analyze its pathological characteristics, diagnostic procedures and treatment strategies. A PubMed (https://www.ncbi.nlm.nih.gov/pubmed/) search was performed for studies published between January 1990 and July 2017. Full-text articles were identified using the terms, ‘hyperfunctioning thyroid carcinoma/cancer’, ‘malignant hot/toxic thyroid nodule’, or ‘hyperfunctioning papillary/follicular/Hürthle thyroid carcinoma’. Original research papers, case reports and review articles were included. Among all thyroid carcinoma cases included in the present study, the prevalence of follicular thyroid carcinoma (FTC) was ~10%; however, the prevalence of FTC among hyperfunctioning thyroid carcinomas was markedly higher (46.5% in primary and 71.4% in metastatic disease). The size of hyperfunctioning thyroid tumors was considerably larger compared with that of non-hyperfunctioning thyroid tumors, with a mean size of 4.25±2.12 cm in primary hyperfunctioning thyroid carcinomas. In addition, in cases of metastatic hyperfunctioning thyroid carcinoma, tumor metastases were widespread or large in size. The diagnosis of primary hyperfunctioning thyroid carcinoma is based on the following criteria: i) No improvement in thyrotoxicosis following radioactive iodine (RAI) treatment; ii) development of hypoechoic solid nodules with microcalcifications on ultrasound examination; iii) increase in tumor size over a short time period; iv) fixation of the tumor to adjacent structures; and v) signs/symptoms of tumor invasion. The diagnosis of metastatic hyperfunctioning thyroid carcinoma should be considered in patients suffering from thyrotoxicosis who present with a high number of metastatic lesions (as determined by whole-body scanning), or a history of total thyroidectomy. Surgery is the first-line treatment option for patients with primary hyperfunctioning thyroid carcinoma, as it does not only confirm the diagnosis following pathological examination, but also resolves thyrotoxicosis and is a curative cancer treatment. RAI is a suitable treatment option for patients with hyperfunctioning thyroid carcinoma who present with metastatic lesions.

Thyrotoxicosis with concomitant thyroid cancer

Thyrotoxicosis with concomitant thyroid cancer is rare and poorly recognized, which may result in delayed diagnosis, inappropriate treatment and even poor prognosis. To provide a comprehensive guidance for clinicians, the etiology, pathogenesis, diagnosis and treatment of this challenging setting were systematically reviewed. According to literatures available, the etiologies of thyrotoxicosis with concomitant thyroid cancer were categorized into Graves' disease with concurrent differentiated thyroid cancer (DTC) or medullary thyroid cancer, Marine-Lenhart Syndrome with coexisting DTC, Plummer's disease with concomitant DTC, amiodarone-induced thyrotoxicosis with concomitant DTC, central hyperthyroidism with coexisting DTC, hyperfunctioning metastases of DTC and others. The underlying causal mechanisms linking thyrotoxicosis and thyroid cancer were elucidated. Medical history, biochemical assessments, radioiodine uptake, anatomic and metabolic imaging and ultrasonography-guided fine-needle aspiration combined with pathological examinations were found to be critical for precise diagnosis. Surgery remains a mainstay in both tumor elimination and control of thyrotoxicosis, while anti-thyroid drugs, beta-blockers, 131I, glucocorticoids, plasmapheresis, somatostatin analogs, dopamine agonists, radiation therapy, chemotherapy and tyrosine kinase inhibitors should also be appropriately utilized as needed.

Thyrotoxicosis: Diagnosis and Management

Thyrotoxicosis is the clinical manifestation of excess thyroid hormone action at the tissue level due to inappropriately high circulating thyroid hormone concentrations. Hyperthyroidism, a subset of thyrotoxicosis, refers specifically to excess thyroid hormone synthesis and secretion by the thyroid gland. We performed a review of the literature on these topics utilizing published data in PubMed and MEDLINE. In this review, we discuss the more common etiologies of thyrotoxicosis, focusing on the current approach to diagnosis and management, new trends in those directions, and potential upcoming changes in the field.

An upper cervical cord compression secondary to occult follicular thyroid carcinoma metastases successfully treated with multiple radioiodine therapies: A clinical case report

RATIONALE

The spine is the most common site of bone metastases due to thyroid cancer; however, spinal cord compression as a complication of metastatic thyroid cancer is very rare.

PATIENT CONCERNS

A 48-year-old female patient was presented to the Neurosurgical Department, complaining of progressive back neck pain with bilateral upper extremities numbness and weakness for 4 months.

DIAGNOSIS

Imaging studies revealed osteolytic destruction in bodies and accessories of the second and third cervical vertebrae with a huge soft-tissue mass compressing spinal cord and causing swelling. After the neurosurgical decompression surgery, the pathological examination established a metastatic follicular carcinoma originating from the thyroid gland.

INTERVENTIONS

Her cervical spinal metastases were hardly removed by surgery and the risks of external beam radiation therapy (EBRT) were very high. So she underwent a total thyroidectomy and received multiple radioiodine (RAI) and concomitant glucocorticoid therapies postoperatively. Radioiodine whole-body scan (WBS) showed multiple abnormal radioiodine uptakes. Then single-photon emission tomography/computed tomography (SPECT/CT) located these spinal metastases involving cervical, lumbar, and sacral vertebrae.

OUTCOMES

After 5 times RAI therapy, her thyroglobulin obviously decreased, with the cervical lesion shrinkage and no spinal cord edema.

LESSONS

RAI therapy and concomitant glucocorticoid therapy could be used for spinal metastases of FTC, even with spinal cord compression.

Clinical management and outcomes in patients with hyperfunctioning distant metastases from differentiated thyroid cancer after total thyroidectomy and radioactive iodine therapy

BACKGROUND

Hyperfunctioning distant metastasis (HFDM) from differentiated thyroid cancer (DTC) is a rare entity. This study aimed to assess the outcomes of DTC patients presenting with HFDM after total thyroidectomy and radioactive iodine therapy.

METHODS

A total of 5367 DTC patients treated with (131)I after total thyroidectomy were analyzed retrospectively from January 1991 to June 2013. Therapeutic efficacy was evaluated based on changes in serum thyroglobulin (Tg) and anatomical imaging changes in metastatic lesions. The relationships between survival time and several variables were assessed by univariate and multivariate analyses using the Kaplan-Meier method and Cox's proportional hazards model respectively.

RESULTS

Thirty-eight patients with HFDM from DTC were diagnosed, including four with hyperthyroidism, four with subclinical hyperthyroidism, and three with subclinical hypothyroidism. The remaining 27 were euthyroid. Of 25 patients with lung metastases, 84% (21/25) showed disappearance or shrinkage of lung nodules; of 24 patients with bone metastases, 66.67% (16/24) exhibited no obvious imaging changes in metastatic bone lesions after (131)I therapy. Serum Tg decreased significantly in 81.58% (31/38) and increased in 18.42% (7/38) after (131)I therapy. The 10-year survival rate of DTC patients with HFDM was 65.79% (25/38). Multivariate analyses identified age at occurrence of distant metastases (<45 years), only lung metastases, and papillary thyroid cancer (PTC; p=0.032, NA, and 0.043) as independent predictors of survival.

CONCLUSION

The response of hyperfunctioning lung metastases to (131)I treatment was better than that of non-hyperfunctioning lung metastases in DTC, while hyperfunctioning bone metastases responded similarly compared to non-hyperfunctioning bone metastases. Patients younger than 45 years at occurrence of distant metastases, those with only lung metastases, and patients with PTC had better prognoses.

Euthyroid status after total thyroidectomy due to functioning lung metastases from a clear cell variant of papillary thyroid carcinoma

BACKGROUND

Although functioning thyroid cancer metastases have been reported, they have almost never been reported for the clear cell variant of papillary thyroid carcinoma (PTC). Here we describe a patient with disseminated lung metastases of the clear cell variant of PTC who presented in the euthyroid state despite discontinuance of levothyroxine after total thyroidectomy.

PATIENT FINDINGS

A 49-year-old woman underwent total thyroidectomy for the clear cell variant of PTC in March 2002. Levothyroxine replacement was initiated after total thyroidectomy, but the patient was lost to follow-up 5 years after the operation. She did not take any levothyroxine for 4 years. Upon presentation to our institution, her initial thyroid function tests were a serum thyroid-stimulating hormone (TSH) of 4.51 mIU/L (0.30-5.00), total triiodothyronine of 82 ng/dL (60-181), and free thyroxine of 1.21 ng/dL (0.89-1.76). The results of workups, including thyroid ultrasonography, chest computed tomography (CT) scan, and fluorine-18 fluorodeoxyglucose positron emission tomography (18F-FDG PET)/CT, revealed that she had multiple metastases in the cervical lymph nodes and both lungs. She received 0.9 mg of recombinant human TSH (rhTSH) for 2 consecutive days followed by administration of 200 mCi 131I. A therapeutic whole body scan after 131I administration demonstrated intense uptake in the whole lung fields, suggesting functioning lung metastases.

SUMMARY

It is extremely rare for metastatic PTC, even though it is a well-differentiated thyroid carcinoma, to produce a sufficient amount of thyroid hormones to result in euthyroid state after total thyroidectomy. To our knowledge, this is the first report of functioning lung metastases of the clear cell variant of PTC after total thyroidectomy that produced enough thyroid hormone to restore a euthyroid state.

CONCLUSION

Functioning metastases from recurred PTC, particularly of the clear cell variant, are very rare. When they occur, rhTSH is required to prepare these patients for treatment with ablative doses of radioactive iodine (131I).