Medullary thyroid carcinoma associated with hyperthyroidism: a case report and review of the literature

A Correlational Analysis of Phthalate Exposure and Thyroid Hormone Levels in Common Bottlenose Dolphins (Tursiops truncatus) from Sarasota Bay, Florida (2010–2019)

Simple Summary

Phthalate exposure is prevalent in common bottlenose dolphins sampled from Sarasota Bay, Florida. With evidence of potential adverse effects as identified in human and laboratory studies, there is a concern for bottlenose dolphin health. This study investigated potential correlations between serum hormone levels and urinary phthalate metabolite concentrations to begin to understand whether health effects would be expected in dolphins. We observed a positive relationship between free thyroxine and mono(2-ethylhexyl) phthalate (MEHP) for both adult female and male dolphins, suggesting potential associations with normal thyroid production.

Abstract

Phthalates are chemical esters used to enhance desirable properties of plastics, personal care, and cleaning products. Phthalates have shown ubiquitous environmental contamination due to their abundant use and propensity to leach from products to which they are added. Following exposure, phthalates are rapidly metabolized and excreted through urine. Common bottlenose dolphins (Tursiops truncatus) sampled from Sarasota Bay, Florida, have demonstrated prevalent di(2-ethylhexyl) phthalate (DEHP) exposure indicated by detectable urinary mono(2-ethylhexyl) phthalate (MEHP) concentrations. Widespread exposure is concerning due to evidence of endocrine disruption from human and laboratory studies. To better understand how phthalate exposure may impact dolphin health, correlations between relevant hormone levels and detectable urinary MEHP concentrations were examined. Hormone concentrations measured via blood serum samples included triiodothyronine (T3), total thyroxine (T4), and free thyroxine (FT4). Urinary MEHP concentrations were detected in 56% of sampled individuals (n = 50; mean = 8.13 ng/mL; s.d. = 15.99 ng/mL). Adult female and male FT4 was significantly correlated with urinary MEHP concentrations (adult female Kendall’s tau = 0.36, p = 0.04; adult male Kendall’s tau = 0.42, p = 0.02). Evidence from this study suggests DEHP exposure may be impacting thyroid hormone homeostasis. Cumulative effects of other stressors and resultant endocrine impacts are unknown. Further research is warranted to understand potential health implications associated with this relationship.

A Rare Coexistence of Medullary Thyroid Cancer with Graves Disease: A Case Report and Systematic Review of the Literature

Patient: Male, 39

Final Diagnosis: Medullary thyroid cancer

Symptoms: Hyperthyroidism symptoms

Medication: —

Clinical Procedure: Total thyroidectomy

Specialty: Surgery

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.

[Association of hyperthyroidism with differentiated thyroid cancer]

The presence of hyperthyroidism is no longer an insurance against the occurrence of thyroid cancer. The combination of the two is common. This is a retrospective study of 355 files of patients followed for differentiated thyroid cancer in the endocrinology department at CHU IBN ROCHD from 1986 to 2014. 12 of those patients were followed for hyperthyroidism, and a fortuitous association with differentiated thyroid cancer was found during the anatomopathological exam, giving us a 3.38% prevalence. The average age of discovery is 44.8 years, with a marked female predominance (8/12). Eight patients had a toxic nodule, 3 had Basedow's goiters, and one had Graves' disease. All underwent total thyroidectomy. In all patients, the cancer was a papillary carcinoma. Microcarcinoma was the most predominant (6 patients). An insular carcinoma was found in a patient with spinal and retro-orbital metastases. Treatment with radioactive iodine was prescribed to five patients. The diagnosis of hyperthyroidism does not eliminate the possibility of an associated thyroid cancer. Malignancy should always be kept in mind and therefore lead to a diagnostic approach comparable to that for any thyroid nodule.

Hyperthyroidism in Patients with Thyroid Cancer

We present a retrospective case series of patients with hyperthyroidism and thyroid cancer. Our goal was to look at their clinical characteristics and outcomes to determine which patients would require further investigation. We reviewed the case notes of all patients with a histopathologic diagnosis of thyroid cancer and biochemical evidence of hyperthyroidism who had been treated at a thyroid cancer center from January 2006 through October 2013. During that time, 66 patients had been diagnosed with thyroid cancer. Of these, 8 patients (12%)—all women, aged 29 to 87 years (mean: 55.6; median: 50.5)—had biochemical evidence of hyperthyroidism. Among these 8 patients, 4 had an autonomously functioning toxic nodule (AFTN), 3 were diagnosed with Graves disease, and 1 had a toxic multinodular goiter. Five patients had suspicious features on preoperative ultrasonography. All 8 patients were diagnosed with the papillary type of thyroid carcinoma. The mean size of the tumor in the 4 patients with AFTN was significantly larger than it was in those with Graves disease (42.3 ± 23.8 mm vs. 3.8 ± 1.6; p = 0.04). The 3 patients with Graves disease all had incidentally found papillary microcarcinoma. Between these two groups, the patients with AFTN had a poorer prognosis; 2 of them had extracapsular invasion and lymph node metastasis, and another died of her disease. We found that the incidence of hyperthyroidism in thyroid cancer patients was relatively high (12%). In contrast to what has previously been reported in the literature, patients with AFTN seem to have more aggressive disease and poorer outcomes than do patients with Graves disease. Any suspicious nodule associated with hyperthyroidism should be evaluated carefully.

Nodular Graves' disease with medullary thyroid cancer

Co-existence of thyroid nodules with Graves' disease has been reported in various studies. 10-15% of such nodules harbor thyroid cancer with papillary thyroid cancer being the commonest. Medullary thyroid cancer (MTC) in nodules associated with Graves' disease is rare. On literature survey, we came across 11 such cases reported so far. We report a 62-year-old female with Graves' disease who also had a thyroid nodule that on fine-needle aspiration cytology and the subsequent postthyroidectomy histopathological examination was reported to be MTC.

A high level of carcinoembryonic antigen as initial manifestation of medullary thyroid carcinoma in a patient with subclinical hyperthyroidism

Carcinoembryonic antigen (CEA), a tumor marker with a glycoprotein structure, is frequently used in follow-up gastrointestinal malignancies. CEA levels may also increase in neuroendocrine tumors, including medullary thyroid carcinoma (MTC), and in some benign diseases. Patients whose blood tests show high CEA levels should have additional tests regarding MTC. Although MTC comprises only 3%-11% of all thyroid cancers, it should be tested because it has a poor prognosis and may accompany multiple endocrine neoplasia. We present the case of a 76-year-old man with subclinical hyperthyroidism with sporadic MTC who presented with initial high serum CEA levels. He underwent total thyroidectomy and left modified neck dissection. Pathologic specimens stained strongly for CEA. The patient's blood was analyzed for mutations in exons 10, 11, 13, 14, 15, and 16, but the RET proto-oncogene revealed no mutations. The patient was regularly followed by measurement of serum CEA levels and performance of positron emission tomography-computed tomography. Seventeen months after surgery, the patient has remained well and showed no signs of tumor recurrence.