Cases of metastases to the thyroid gland seem to be increasing in recent years. The clinical and ultrasonographic findings of diffuse metastases have been sparsely reported. Thirteen cases of diffuse metastases to the thyroid gland were documented by thyroid ultrasonography-guided fine needle aspiration cytology between 2004 and 2013. We retrospectively reviewed the patients with diffuse thyroid metastases. The most common primary site was the lung (n=9), followed by unknown origin cancers (n=2), cholangiocarcinoma (n=1), and penile cancer (n=1). Eleven patients were incidentally found to have thyroid metastases via surveillance or staging FDG-PET. Other 2 patients were diagnosed during work-up for hypothyroidism and palpable cervical lymph nodes. On ultrasonography, the echogenicity of the enlarged thyroid gland was heterogeneously hypoechoic or isoechoic, and reticular pattern internal hypoechoic lines were observed without increased vascularity found by power Doppler ultrasonography (3 right lobe, 2 left lobe, and 8 both lobes). In the 8 patients who had involvement of both lobes, 3 had hypothyroidism. In conclusion, ultrasonographic finding of diffuse metastasis is a diffusely enlarged heterogeneous thyroid with reticular pattern internal hypoechoic lines. Thyroid function testing should be performed in all patients with diffuse thyroid metastases, especially those with bilateral lobe involvement.Graphical Abstract

Having a high TSH level within the normal range is an independent risk factor for DTC, and may contribute to the initiation of thyroid carcinogenesis. TSH levels in patients with thyroid nodules may be used as diagnostic adjuncts for the identification of high-risk patients, who require further investigation and/or surgical intervention.

Background Thyroid immune-related adverse events (IRAEs) have been reported in patients treated with programmed cell death protein-1 (PD-1) and programmed cell death protein-ligand 1 (PD-L1) inhibitors. We investigated the incidence and clinical course of PD-1/PD-L1 inhibitor-induced thyroid IRAEs, and identified predictable clinical risk factors of thyroid IRAEs, in particular, overt hypothyroidism (OH). Methods We retrospectively reviewed the medical records of 325 cancer patients receiving PD-1/PD-L1 inhibitor in a tertiary referral center. Results A total of 50.5% (164/325) of patients experienced at least one abnormal thyroid function following PD-1/PD-L1 inhibitor. Eighty-four patients (51.2%) of them recovered to normal thyroid function during follow-up. In overall population, 25 patients (7.7%) required thyroid hormone replacement therapy due to PD-1/PD-L1 inhibitor-induced OH. Patients who progressed to OH showed significantly higher baseline thyroid stimulating hormone level and longer duration of PD-1/PD-L1 inhibitor therapy than those without thyroid dysfunction or OH (both P <0.001). Median time interval to the development of OH was 3 months after the therapy. OH was significantly associated with positive anti-thyroid peroxidase antibody at baseline and anti-thyroglobulin antibody during the therapy than those without thyroid dysfunction or OH ( P =0.015 and P =0.005, respectively). We observed no patients with OH who were able to stop levothyroxine replacement after the cessation of PD-1/PD-L1 inhibitor therapy. Conclusion PD-1/PD-L1 inhibitor-induced thyroid dysfunctions are considerably reversible; however, OH is irreversible requiring levothyroxine replacement even after stopping the therapy. Positive thyroid autoantibodies may predict the progression to OH.

Background Although infrequent, distant metastasis from differentiated thyroid cancer is the main cause of mortality in patients and mostly involves the lung, bone, and brain. Distant metastases to other sites in differentiated thyroid cancer patients are rare, thus, the clinical course of unusual metastases has not been adequately researched. In the present study, the clinicopathological findings and treatment outcomes of unusual metastases in differentiated thyroid cancer patients in Korea were evaluated.

IntroductionSeveral studies have reported a high frequency of papillary thyroid cancer (PTC) in patients with acromegaly. The aim of this study was to determine the prevalence and predictors of thyroid cancer in patients with acromegaly and to investigate the frequency of the BRAF V600E mutation in PTC patients with and without acromegaly.Materials and MethodsWe conducted a retrospective study of 60 patients with acromegaly. Thyroid ultrasonography (US) and US-guided fine needle aspiration were performed on nodules with sonographic features of malignancy. We selected 16 patients with non-acromegalic PTC as a control group. The BRAF V600E mutation was analyzed in paraffin-embedded surgical specimens of PTC by real-time polymerase chain reaction, and tumor specimens from patients with PTC were stained immunohistochemically with an antibody against insulin-like growth factor-1 receptor β (IGF-1Rβ).ResultsThyroid cancer was found in 15 (25.0%) patients. No differences in age, sex, initial growth hormone (GH) and IGF-1 percentage of the upper limit of normal values or treatment modalities were observed between patients with and without PTC. Acromegaly was active in 12 of 15 patients at the time of PTC diagnosis; uncontrolled acromegaly had a significantly higher frequency in the PTC group (60%) than in the non-PTC group (28.9%) (p = 0.030). The BRAF V600E mutation was present in only 9.1% (1/11) of PTC patients with acromegaly, although 62.5% (10/16) of control patients with PTC had the mutation (p = 0.007). IGF-1Rβ immunostaining showed moderate-to-strong staining in all malignant PTC cells in patients with and without acromegaly. Significantly less staining for IGF-1Rβ was observed in normal adjacent thyroid tissues of PTC patients with acromegaly compared with those without (p = 0.014).ConclusionThe prevalence of PTC in acromegalic patients was high (25%). An uncontrolled hyperactive GH-IGF-1 axis may play a dominant role in the development of PTC rather than the BRAF V600E mutation in patients with acromegaly.

BackgroundNon-thyroidal illness (NTI) refers to changes in thyroid hormone levels in critically ill patients in the absence of primary hypothalamic-pituitary-thyroid dysfunction, and these abnormalities usually resolve after clinical recovery. However, NTI can be accompanied by primary thyroid dysfunction. We report herein a case of a woman with NTI accompanied by primary hyperthyroidism.Case presentationA 52-year-old female was admitted to the intensive care unit with heart failure and atrial fibrillation. She had a longstanding thyroid nodule, and a thyroid function test revealed low levels of triiodothyronine and free thyroxine as well as undetectable thyroid stimulating hormone (TSH). She was diagnosed with NTI, and her TSH level began to recover but not completely at discharge. The thyroid function test was repeated after 42 months to reveal primary hyperthyroidism, and a thyroid scan confirmed a toxic nodule.ConclusionThis case suggests that although NTI was diagnosed, primary hyperthyroidism should be considered as another possible diagnosis if TSH is undetectable. Thyroid function tests should be repeated after clinical recovery from acute illness.

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BackgroundAntithyroid drugs (ATDs) can lead to the development of agranulocytosis, which is the most serious adverse effect. Characteristics of ATD-induced agranulocytosis (AIA) have seldom been reported due to the rarity. In this study, we characterized the clinical features for AIA in Korean patients.MethodsWe retrospectively reviewed data from patients with AIA diagnosed between 1997 and 2014 at four tertiary hospitals. Agranulocytosis was defined as an absolute neutrophil count (ANC) below 500/mm3.ResultsThe mean age of the patients (11 males, 43 females) was 38.2±14.9 years. Forty-eight patients (88.9%) with AIA had fever and sore throat on initial presentation, 20.4% of patients developed AIA during the second course of treatment, and 75.9% of patients suffered AIA within 3 months after initiation of ATD. The patients taking methimazole (n=39) showed lower levels of ANC and more frequent use of granulocyte-macrophage colony-stimulating factor than propylthiouracil (n=15) users. The median duration of agranulocytosis was 5.5 days (range, 1 to 20). No differences were observed between the long (≥6 days) and short recovery time (≤5 days) groups in terms of age, gender, ATDs, duration of ATDs, or initial ANC levels. Four patients (7.4%) who were taking ATDs for less than 2 months died of sepsis on the first or second day of hospitalization.ConclusionThe majority of AIA incidents occur in the early treatment period. Considering the high fatality rate of AIA, an early aggressive therapeutic approach is critical and patients should be well informed regarding the warning symptoms of the disease.