A case report of hyperfunctioning metastatic thyroid cancer and rare I-131 avid liver metastasis

Abstract

Thyroid cancer is usually, relatively hypofunctional; most patients with thyroid cancer are clinically euthyroid. The combination of thyroid cancer and thyrotoxicosis is not common. We herein, report a case of follicular thyroid cancer with hyperfunctioning metastasis in a 43-year-old woman who presented with thyrotoxicosis, a cold right thyroid nodule, and low I-131 uptake at the thyroid bed. An additional total body scan with I-131 revealed a large radioiodine avid osteolytic bone metastasis with soft tissue masses and liver metastasis. The patient received treatment with total thyroidectomy, methimazole, and I-131 at a cumulative dose of 600 mCi along with recombinant human thyroid-stimulating hormone before the first I-131 treatment and palliative radiation. The patient had normal liver function test and experienced a mild degree of bone marrow suppression after I-131. At the 2-year follow-up, the patient was still alive with the progression of bone metastases but was doing well with less severe thyrotoxicosis, good ambulation, and an Eastern Cooperative Oncology Group performance status of 2. Clinicians should be aware of the unusual concurrent presentation of thyrotoxicosis and thyroid cancer, a differential diagnosis in patients with thyrotoxicosis and low or normal radioiodine uptake over the neck and also potential pitfalls during radionuclide treatment.

Thyrotoxicosis with concomitant thyroid cancer

“…Although most hyperfunctioning metastases are FTC-derived, metastases from PTC can also induce thyrotoxicosis (Danilovic et al 2015, Biyi et al 2016. The major sites of hyperfunctioning metastases are pulmonary and bone (Haq et al 2007, Nishihara et al 2010, Biyi et al 2016, and the rare metastases site of the liver was also reported (Takano et al 2006, Kunawudhi et al 2016. According to the study of Qiu, 0.71% DTC patients present with hyperfunctioning metastases, and the 10-year survival rate of patients with hyperfunctioning metastases was 65.79%, patients younger than 45 years at occurrence of distant metastases, those with only lung metastases, and patients with PTC had better prognoses (Qiu et al 2015).…”

“…Based on previous studies, the prescribed activity of 131 I to treat hyperfunctioning metastases of DTC varies from 13 mCi to 200 mCi (Tan et al 2009, Nishihara et al 2010, Kunawudhi et al 2016. Although there is no clear criterion for the dose of 131 I in treatment of functional metastases, it should be noted that high doses of 131 I could cause a large amount of tumor cell destruction, releasing a burst of thyroid hormones and causing thyrotoxic storm if the patients were not prepared adequately before and after 131 I treatment.…”

“…In theory, thyrotoxicosis with suppressed TSH should lead to a lower incidence of thyroid cancer than that observed in euthyroid patients (Fiore & Vitti 2012). In practice, thyroid cancer is typically less efficient in iodine uptake and thyroxine synthesis than normal parenchymal, and most patients with thyroid cancer present with euthyroid or clinical/subclinical hypothyroidism (Kunawudhi et al 2016). However, an increasing number of studies have demonstrated that more attention should be paid to the management of thyrotoxicosis with concurrent thyroid cancer since the first case of hyperfunctioning thyroid cancer metastases was successfully treated with radioactive iodine ( 131 I) (Seidlin et al 1946).…”

Excellent Response to Multimodal Therapy Approach in Hyperfunctioning Metastatic Follicular Thyroid Carcinoma Diagnosed on 123I-SPECT/Ultrasound Fusion Imaging

“…The scan showed multiple iodine-avid mediastinal and bilateral hilar lymph node, as well as lung and bone metastases. 2,4,7 Dosimetric analyses revealed a total 123 I uptake of 31.8% within the iodine-avid tumor lesions. First step, thyrostatic medication was initiated to treat the manifest hyperthyroidism.…”

“…Contrary to the expectation, scintigraphy scan revealed a large area of increased nuclide uptake of the left thyroid lobe with almost complete suppression of the remaining parenchyma ( A2 ). Assuming that hyperfunctionality excludes malignancy with high probability, further clarification of the discrepant findings was warranted 2–5 . Fine-needle aspiration cytology yielded an equivocal result (group III) and could not contribute to the suspected diagnosis of thyroid cancer.…”