Thyroid dysfunction following pregnancy and implications for breastfeeding

Subclinical autoimmune thyroiditis exacerbates after delivery through immune rebound mechanisms and results in 5 types of thyroid dysfunction. The prevalence of postpartum thyroid dysfunction is around 5% in mothers in the general population. Typically, an exacerbation induces destructive thyrotoxicosis followed by transient hypothyroidism, known as postpartum thyroiditis. Late development of permanent hypothyroidism is found frequently and patients should be followed up once every one to two years. Destructive thyrotoxicosis in postpartum thyroiditis should carefully be differentiated from post-partum Graves' disease. Postpartum thyroiditis typically occurs 1-4 months after parturition whereas Graves' disease develops at 4-12 months postpartum. Anti-TSH receptor antibodies (TRAb) are typically positive and thyroid blood flow is high in Graves' disease, whereas these features are absent in postpartum thyroiditis. Postpartum Graves' disease should be treated with antithyroid drugs.

Papillary thyroid carcinomas are highly obscured by inflammatory hypoechoic regions caused by subacute thyroiditis: a longitudinal evaluation of 710 patients using ultrasonography

Subacute thyroiditis is a self-limited inflammatory disease and very few patients undergo ultrasonographic re-examination if no nodules are found at the initial examination. The objective of the study was to assess the diagnostic accuracy of ultrasonography in detecting nodular lesions in patients with subacute thyroiditis. We conducted a longitudinal study involving 710 patients with subacute thyroiditis who underwent ultrasonographic examinations in a single center between 2008 and 2018. These examinations were performed at initial diagnosis and during follow-up, with subsequent evaluation of nodules using fine needle aspiration cytology. Ultrasonographic examination used for the initial screening of thyroid nodules in patients with subacute thyroiditis showed a sensitivity of 72.4%, specificity of 89.0%, positive predictive value of 80.4%, and negative predictive value of 83.8%. Twenty-two patients (3.1%) had concomitant papillary thyroid carcinoma, 10 of whom underwent thyroidectomy while the remaining 12 opted for active surveillance owing to having low-risk microcarcinomas. Approximately 30% of papillary carcinomas (7/22) were identified during follow-up ultrasonography, but not during the initial scan. All tumors in this false-negative group were latently localized in the bilateral hypoechoic regions of the thyroid and showed no calcified components. Of the 15 tumors that were detected during both initial and follow-up examinations, 7 exhibited calcified components and 5 were located in unaffected areas apart from the inflammatory hypoechoic region. Subacute thyroiditis highly obscures any coexisting papillary carcinoma when inflammatory hypoechoic regions are present. Ultrasonographic re-examination after a sufficient interval is indispensable for patients with subacute thyroiditis.

Moderate Frequency of Anti-Thyroglobulin Antibodies in the Early Phase of Subacute Thyroiditis

BACKGROUND

Subacute thyroiditis is generally believed to be induced by viral infection, and little attention has been paid to anti-thyroid antibodies.

OBJECTIVES

Our study aimed to assess the prevalence of anti-thyroid antibodies in patients with subacute thyroiditis.

METHODS

Anti-thyroglobulin (TgAb) and anti-thyroid peroxidase antibodies (TPOAb) were measured with 4 different immunoassay kits currently used in 40 patients in the early phase of subacute thyroiditis.

RESULTS

The proportion of samples positive for TgAb was 52.5 ± 13.7% (mean of 4 kits), which was significantly (p < 0.05) higher than that positive for TPOAb (15.6 ± 6.5%). The prevalence of positive TgAb alone (negative TPOAb) was also significantly higher than that of TPOAb alone (negative TgAb). TgAb titers decreased or disappeared within 4 months to 6 years in 6 patients.

CONCLUSIONS

Patient samples were moderately positive for TgAb initially, but the titer decreased or disappeared afterwards in subacute thyroiditis.

Platelet Activation Induced by Combined Effects of Anticardiolipin and Lupus Anticoagulant IgG Antibodies in Patients with Systemic Lupus Erythematosus

Antiphospholipid antibodies (aPL) are well known to be associated with arterial and venous thrombosis. In a series of 180 patients with systemic lupus erythematosus (SLE), the prevalence of arterial thrombosis was obviously higher in the patients who had both anticardiolipin antibodies (aCL) and lupus anticoagulant (LA) (17/35, 48.6%, p <0.05) (Table 1) than in the other patients bearing aCL or LA alone or neither of them (2/145, 1.4%). Since a substantial fraction of the former group of patients with arterial thrombosis also had thrombocytopenia (12/17, 70.6%), there was a possibility that aCL and LA might have enhanced platelet activation and aggregation. To test this possibility, we studied the in vitro effects of aCL and LA on the enhancement of platelet activation by flow cytometric analysis using anti-CD62P and anti-CD41 monoclonal antibodies directed against platelet activation-dependent granule-external membrane (PADGEM) protein and platelet glycoprotein IIb (GPIIb), respectively. Platelet activation defined by the surface expression of CD62P was not induced by aCL+·LA+ plasma only, but was significantly augmented by aCL+·LA+ plasma in combination with adenosine diphosphate (ADP) at a low concentration that had only a modest effect on platelet activation. In contrast, aCL+·LA–, aCL–·LA+ and aCL–·LA– plasma samples were incapable of enhancing platelet activation in the presence or absence of ADP stimulation. In addition to plasma samples, the purified IgG from aCL+·LA+ plasma (aCL+·LA+-IgG) also yielded apparent enhancement of platelet activation induced by ADP. Furthermore, platelet activation was generated by the mixture of aCL+·LA–-IgG and aCL–·LA+-IgG fractions prepared from individual patients, but not by each fraction alone. These results suggest that aCL and LA may cooperate to promote platelet activation, and may be involved, at least partially, in the pathogenesis of arterial thrombosis and thrombocytopenia in patients with SLE.

Comparison of thyroglobulin and thyroid peroxidase antibodies measured by five different kits in autoimmune thyroid diseases

It is generally believed that the detection of thyroid peroxidase antibodies (TPOAb) is superior to that of thyroglobulin antibodies (TgAb) for the diagnosis of Hashimoto's thyroiditis. However, limited data are available on the comparison of TgAb and TPOAb prevalence as a diagnostic measurement for Hashimoto's thyroiditis using sensitive immunoassays. We herein used five different current immunoassay kits (A-E) to compare the prevalence of TgAb and TPOAb in Hashimoto's thyroiditis (n = 70), Graves' disease (n = 70), painless thyroiditis (n = 50), and healthy control subjects (n = 100). In patients with Hashimoto's thyroiditis, positive TgAb was significantly more frequent than positive TPOAb in kits A-D (mean ± SD of the four kits: 98.6 ± 1.7 vs 81.4 ± 2.0%). In patients with Graves' disease, TgAb prevalence was almost equivalent to that of TPOAb in five kits. Patients with painless thyroiditis exhibited positive TgAb significantly more frequently than positive TPOAb in kits A-D (73.5 ± 4.1 vs 33.0 ± 3.4%). The prevalence of TgAb alone was significantly higher than that of TPOAb alone in both Hashimoto's thyroiditis and painless thyroiditis in kits A-D. In kit E, TgAb and TPOAb prevalence did not differ significantly for any disease, and TgAb distribution was different from other kits. In conclusion, the prevalence of TgAb was higher than that of TPOAb in patients with Hashimoto's thyroiditis and painless thyroiditis using commercially available kits. We suggest that TgAb immunoassay is the first choice of screening test for thyroid autoimmune abnormalities in Japan.

Comparative frequency of four different types of pregnancy-associated thyrotoxicosis in a single thyroid centre

Background

Pregnancy and delivery markedly influence thyroid function. However, the comparative prevalence of gestational thyrotoxicosis (GT), new onset of Graves’ disease during pregnancy (GD during pregnancy), postpartum destructive thyrotoxicosis (PPT), and postpartum Graves’ thyrotoxicosis (PPGD) has not yet been determined.

Methods

We prospectively registered and performed a review of 4127 consecutive non treated female patients with thyrotoxicosis, seen between August 2008 and December 2013 in our outpatient clinic of Kuma Hospital. 187 out of the 4127 women had new diagnosis of thyrotoxicosis during pregnancy or in the postpartum period. We investigated the prevalence of new diagnosis of GT, GD during pregnancy, PPT and PPGD and compared the characteristics of these types of thyrotoxicosis. The postpartum period is defined as twelve months after delivery.

Results

Out of 187 pregnant or postpartum women, we identified 30 (16.0%) with GT, 13 (7.0%) with GD during pregnancy, 42 (22.5%) with PPT, and 102 (54.5%) with PPGD. The onset time of thyrotoxicosis during pregnancy, i.e., both GT and GD during pregnancy, was delayed by a couple of weeks when hCG peaked at 10 gestational weeks. Seventy-six percent of patients with PPT developed thyrotoxicosis between delivery and 4 months postpartum; on the other hand, 83.3% of patients with PPGD developed thyrotoxicosis at 6 months postpartum or later.

Conclusions

We named gestational thyrotoxicosis, new onset of Graves’ disease during pregnancy, postpartum destructive thyrotoxicosis, and postpartum Graves’ thyrotoxicosis as pregnancy-associated thyrotoxicosis. A clinically significant number of women developed Graves’ disease in the postpartum period in a single thyroid centre.

Biochemical Markers Reflecting Thyroid Function in Athyreotic Patients on Levothyroxine Monotherapy

BACKGROUND

Some investigators reported that among athyreotic patients on levothyroxine (LT4) monotherapy following total thyroidectomy, the patients with normal serum thyrotropin (TSH) levels had mildly low serum free triiodothyronine (fT3) levels, whereas the patients with mildly suppressed serum TSH levels had normal serum fT3 levels, and the patients with strongly suppressed serum TSH had elevated serum fT3 levels. The objective of the present study was to clarify which of these three patient groups is closer to their preoperative euthyroid condition.

METHODS

A total of 133 consecutive euthyroid patients with papillary thyroid carcinoma who underwent a total thyroidectomy were prospectively studied. The patients' serum levels of lipoproteins, sex hormone-binding globulin, and bone metabolic markers measured preoperatively were compared with the levels measured at postoperative LT4 therapy 12 months after the thyroidectomy.

RESULTS

The postoperative serum sex hormone-binding globulin (p < 0.001) and bone alkaline phosphatase (p < 0.01) levels were significantly increased in the patients with strongly suppressed TSH levels (≤0.03 μIU/mL). The postoperative serum low-density lipoprotein cholesterol levels were significantly increased (p < 0.05), and the serum tartrate-resistant acid phosphatase-5b levels were significantly decreased (p < 0.05) in the patients with normal TSH (0.3 < TSH ≤5 μIU/mL). In the patients with mildly suppressed TSH (0.03 < TSH ≤0.3 μIU/mL) and fT3 levels equivalent to their preoperative levels, all metabolic markers remained equivalent to their preoperative levels.

CONCLUSIONS

The serum biochemical markers of thyroid function in patients on LT4 following total thyroidectomy suggest that the patients with mildly suppressed TSH levels were closest to euthyroid, whereas those with normal TSH levels were mildly hypothyroid and those with strongly suppressed TSH levels were mildly hyperthyroid. These data may provide novel information on the management of patients following total thyroidectomy for thyroid cancer or benign thyroid disease.

Partial prediction of postpartum Graves' thyrotoxicosis by sensitive bioassay for thyroid-stimulating antibody measured in early pregnancy

Graves' disease often occurs after delivery. However, it has been difficult to predict who will develop Graves' hyperthyroidism. We attempted to predict postpartum onset of Graves' disease by measuring anti-TSH receptor antibodies (TRAb) and thyroid-stimulating antibodies (TSAb) in early pregnancy. TRAb was measured by a third generation assay and TSAb was measured by a newly developed sensitive bioassay. In 690 early pregnant women, 2 showed borderline TRAb positive reactions. However, none of them developed Graves' disease after delivery. Thirty-eight of 690 pregnant women were positive for anti-thyroid peroxidase antibodies (TPOAb) and 4 were positive for TSAb. Two of these 4 women developed postpartum Graves' hyperthyroidism. These findings indicate that the third generation TRAb assay was not useful, but that the sensitive TSAb bioassay was moderately useful for predicting the postpartum onset of Graves' hyperthyroidism.

Tumor protrusion with intensive blood signals on ultrasonography is a strongly suggestive finding of follicular thyroid carcinoma

AIM

It is difficult to differentiate follicular carcinomas (FC) from follicular adenomas (FA) because ultrasonography and cytology provide very similar findings. FC is histopathologically diagnosed to have capsular and/or vascular invasion. In a few patients, tumor protrusions are observed by preoperative ultrasonography as large forms of capsular invasion of follicular carcinomas. The aim of the study was to clarify the predictive value of tumor protrusions on preoperative ultrasonography for follicular carcinomas.

MATERIAL AND METHODS

A total of 531 patients (FC: 184 patients, FA: 347 patients) undergoing thyroid surgery were included in this study. A tumor protrusion on ultrasonography was defined as follows: 1) a solid tumor extending beyond a marginal line of capsular zone of the main tumor on B-mode ultrasonography; 2) intensive blood signals observed within the protrusion area on Doppler ultrasonography. The large form of capsular invasion was defined if the protrusion lesion was histopathologically diagnosed to be a capsular invasion of follicular carcinoma.

RESULTS

The sensitivity of tumor protrusion was 0.071, specificity 0.994, positive predictive value 0.867, and negative predictive value 0.669 for FC diagnosis. For the large form of capsular invasion in FC the sensitivity of tumor protrusion was 0.813, specificity 0.982, positive predictive value 0.684, and negative predictive value 0.982.

CONCLUSIONS

A tumor protrusion with intensive blood signals extending from the main tumor on ultrasonography strongly suggests a large form of capsular invasion of follicular carcinoma.

Kinetic analyses of changes in serum TSH receptor antibody values after total thyroidectomy in patients with Graves' disease

We often recommend total thyroidectomy for patients with Graves' disease who wish to have a child in the near future in order to prevent fetal or neonatal hyperthyroidism, especially if the patients' serum thyrotropin receptor antibody (TRAb) values are high. The aim of this study was to analyze changes in serum TRAb values using a quantitative third-generation assay after total thyroidectomy and the half-lives of serum TRAb values to estimate the postoperative time needed to achieve the safe TRAb value for mothers. We retrospectively examined the records of 45 Graves' disease patients who underwent a total thyroidectomy and had high serum TRAb values. We also evaluated factors that prolonged the postoperative reduction of serum TRAb values. The serum TRAb values decreased rapidly in most of the patients, especially within the early postoperative (3-month) period. The presence of Graves' ophthalmopathy (GO) (p=0.001), smoking (p=0.004), and serum thyroglobulin values > 0.5 ng/mL at postoperative 12 months (p=0.039) were significantly associated with prolonged half-lives of the serum TRAb values. The median TRAb value half-life was 93.5 days in the patients without GO or smoking, 162.5 days in the patients with GO or smoking, and 357.4 days in the patients with both GO and smoking. Our findings indicate that using the half-life of patients' serum TRAb values determined by this third-generation assay would be effective to evaluate the reduction of serum TRAb values after total thyroidectomy and to estimate the postoperative time needed to achieve the maternal safe value.

A Novel Germline Mutation of KEAP1 (R483H) Associated with a Non-Toxic Multinodular Goiter

BACKGROUND

A germline mutation of KEAP1 gene was reported as a novel genetic abnormality associated with familial multinodular goiter. That report was limited, and the pathogenic features were not well established.

PATIENT FINDINGS

We report a 47-year-old Japanese woman who presented with hyperthyroidism and a large multinodular goiter. The family history was notable for a paternal history of goiter. Graves' disease was diagnosed based on positive TRAb, but scintiscan imaging showed that the patient's radioiodine uptake was restricted in the non-nodular areas, indicating largely cold nodules. A total thyroidectomy was performed. The resected thyroid tissue weighed 209 g, and subsequent pathological findings were benign. The patient had a germline heterozygous KEAP1 mutation, c. 1448 G > A, resulting in an amino acid substitution (p.R483H). A next-generation sequencing analysis covering all known genes associated with multinodular goiter showed no additional germline mutation. The nuclear accumulation of NRF2, a protein associated with KEAP1, was shown at much higher rates in the patient's nodules compared with nodules obtained from four unrelated patients with multinodular goiters.

CONCLUSION

A novel germline mutation (R483H) of KEAP1 gene was associated with the development of a non-toxic multinodular goiter.

Effect of the presence of remnant thyroid tissue on the serum thyroid hormone balance in thyroidectomized patients

OBJECTIVE

We and others recently reported that in total thyroidectomy (TT), serum triiodothyronine (T3) levels during levothyroxine (L-T4) therapy were low compared to the preoperative levels, suggesting that the presence of the thyroid tissue affects the balances of serum thyroid hormone levels. However, the effects of remnant thyroid tissue on these balances in thyroidectomized patients have not been established.

METHODS

We retrospectively studied 253 euthyroid patients with papillary thyroid carcinoma who underwent a TT or hemithyroidectomy (HT). We divided the cases into the TT+supplemental L-T4 (+L-T4) group (n=103); the HT+L-T4 group (n=56); and the HT-alone group (n=94). We compared the postoperative serum levels of free T4 (FT4) and free T3 (FT3) and the FT3/FT4 ratio in individual patients with those of controls matched by serum TSH levels.

RESULTS

The TT+L-T4 group had significantly higher FT4 (P<0.001), lower FT3 (P<0.01) and lower FT3/FT4 (P<0.001) levels compared to the controls. The HT+L-T4 group had FT4, FT3 and FT3/FT4 levels equivalent to those of the controls. The HT-alone group had significantly lower FT4 (P<0.01), equivalent FT3 (P=0.083), and significantly higher FT3/FT4 (P<0.001) ratios than the controls.

CONCLUSIONS

The presence of the remnant thyroid tissue was associated with different thyroid hormone balances in thyroidectomized patients, suggesting that T3 production by remnant thyroid tissue has a substantial effect on the maintenance of postoperative serum T3 levels.

Graves' Disease Patients with Persistent Hyperthyroidism and Diffuse Lymphoplasmacytic Infiltration in the Thyroid Show No Histopathological Compatibility with IgG4-Related Disease

BACKGROUND

IgG4-related disease is a novel disease entity characterized by diffuse lymphoplasmacytic infiltration rich in IgG4-positive plasma cells and fibrosis into multiple organs. There is still controversy over whether some thyroid diseases are actually IgG4-related disease. The objective of this study was to elucidate the clinicopathological features of Graves' disease with diffuse lymphoplasmacytic infiltration in the thyroid.

PATIENTS AND METHODS

Among 1,484 Graves' disease patients who underwent thyroidectomy, we examined their histopathological findings including the degree of lymphoplasmacytic and fibrotic infiltration and levels of IgG4-positive plasma cells in the thyroid. Their clinical pictures were defined by laboratory and ultrasonographic evaluation.

RESULTS

A total of 11 patients (0.74%) showed diffuse lymphoplasmacytic infiltration in the stroma of the thyroid gland. Meanwhile, other patients showed variable lymphoid infiltration ranging from absent to focally dense but no aggregation of plasma cells in the thyroid gland. Based on the diagnostic criteria of IgG4-related disease, 5 of the 11 subjects had specifically increased levels of IgG4-positive plasma cells in the thyroid. Fibrotic infiltration was present in only 1 patient developing hypothyroidism after anti-thyroid drug treatment for 4 years, but not in the other 10 patients with persistent hyperthyroidism. Obliterative phlebitis was not identified in any of the 11 subjects. Thyroid ultrasound examination showed 1 patient developing hypothyroidism who had diffuse hypoechogenicity, but the other hyperthyroid patients had a coarse echo texture.

CONCLUSIONS

In our study, Graves' disease patients with persistent hyperthyroidism who had diffuse lymphoplasmacytic infiltration rich in IgG4-positive plasma cells in the thyroid showed no concomitant fibrosis or obliterative phlebitis.

Metastatic carcinoma to the thyroid gland from renal cell carcinoma: role of ultrasonography in preoperative diagnosis

BACKGROUND

Patients with metastases to the thyroid from renal cell carcinoma (RCC) that need surgical management are not many and unfamiliar to clinicians and thyroid endocrinologists. Therefore, little information is available on ultrasonographic features of metastatic carcinoma in the thyroid. The strategic value of ultrasound in preoperative surgical planning for patients with thyroid nodules has become increasingly appreciated. The purposes of this article are to clarify the ultrasound characteristics of metastatic carcinoma to the thyroid from RCC by evaluating many patients in one institute, and to investigate the role of ultrasonography in preoperative diagnosis.

METHODS

Ten patients with these carcinomas who had undergone surgical management were investigated clinically and ultrasonographically. Ultrasonographic features to be evaluated were the form of involvement in the thyroid, size, shape, pattern, calcifications, vascularity, and tumor thrombus. Clinical features were previous history of RCC, serum thyroglobulin levels, cytology, preoperative diagnosis, and surgery.

RESULTS

Ultrasonographic features of these carcinomas were more likely to involve a solitary, irregular, and solid without calcifications, and prominent intra-tumoral vascularity and tumor thrombus in the vein. These patients tended to be older, and to have relatively late recurrence in the thyroid, RCC in the right kidney as the primary site, and relatively low serum thyroglobulin levels.

CONCLUSIONS

Metastatic carcinomas to the thyroid from RCC presented highly characteristic features on ultrasonography. These ultrasonographic features combined with cytological findings and previous medical history of RCC can provide the optimal process for the preoperative diagnosis of such patients.

Rapid bioassay for detection of thyroid-stimulating antibodies using cyclic adenosine monophosphate-gated calcium channel and aequorin

BACKGROUND

Thyroid-stimulating antibodies (TSAb) are known to be responsible for hyperthyroidism in Graves' disease (GD). The conventional methods to measure TSAb depend on cell-based assays that require cumbersome procedures and a sterilized tissue culture technique. The aim of the present study was to develop a ready-to-use cell-based assay for measuring TSAb activity without requiring sterilized conditions.

METHODS

We developed a new assay kit using a frozen Chinese hamster ovary cell line expressing the thyroid-stimulating hormone receptor, cyclic adenosine monophosphate (cAMP)-gated calcium channel and aequorin, tentatively named the aequorin TSAb assay. Activated stimulatory G-protein-coupled adenylate cyclase increases intracellular cAMP, which then binds to the cyclic nucleotide-gated calcium channel. Activation of this channel allows Ca(2+) to enter the cell, and the influx of Ca(2+) can be measured with aequorin, which is quantified by a luminometer. Results can be obtained in only 4 h without sterilized conditions. TSAb activities were expressed by international units using the NIBSC 08/204 standard.

RESULTS

Positive results of aequorin TSAb were obtained in 197 of 199 (98.9%) of untreated patients with GD. Only 1 of 42 (2.3%) patients with painless thyroiditis had a weakly positive aequorin TSAb. All 45 patients with subacute thyroiditis and 185 normal subjects showed negative aequorin TSAb. As for chronic thyroiditis, all 52 euthyroid patients showed negative aequorin TSAb, but 8 of 50 (16.0%) hypothyroid patients had a positive reaction. However, these positive reactions were not induced by serum thyroid-stimulating hormone (TSH) and were thought to be induced by the stimulating activity of anti-TSH receptor immunoglobulins. Conventional porcine TSAb and Elecsys thyroid-stimulating hormone receptor antibodies were positive in 69.3 and 95.5% of GD, respectively.

CONCLUSION

The aequorin TSAb assay was positive in 98.9% of GD and was more sensitive than the conventional assay. This assay can be conducted in only 4 h without sterilized conditions and is practically useful in general clinical laboratories.

Thyroxine treatment may be useful for subclinical hypothyroidism in patients with female infertility

Infertile women sometimes associated with subclinical hypothyroidism (SCH). The guidelines of the American Endocrine Society, and American Association of Clinical Endocrinologists and American Thyroid Association recommend treatment with thyroxine (T4) for patients with SCH who want to have children. We examined 69 female infertile patients with SCH and the effects of levothyroxine (l-T4) therapy on pregnancy rates and pregnancy outcomes were observed. Fifty-eight (84.1%) patients successfully conceived during the T4 treatment period (Group A), although 17 patients (29.3%) had miscarriage afterward. The remaining 11 patients continued to be infertile (Group B). The median TSH value in Group A before the T4 treatment was 5.46 μIU/mL (range 3.1-13.3) and this significantly decreased to 1.25 μIU/mL (range 0.02-3.75) during the treatment (p<0.001). The estimated duration of infertility before the T4 treatment was 2.8±1.7 years and the duration until pregnancy after the treatment was significantly shorter at 0.9±0.9 years (p<0.001). Shortening of the infertile period after the T4 therapy was observed not only in patients who were treated with assisted reproductive technology (ART) but also in patients who conceived spontaneously in Group A. Administered T4 dose was 54.3±14.2 μg before pregnancy and 68.5±22.8 μg during pregnancy (p<0.001). Anti-thyroid autoantibodies were identified in 42.0% of all patients and no significant difference was observed in positivity between Group A and Group B. High successful pregnancy rate and shorter duration of infertility until pregnancy after T4 treatment strongly suggest that T4 enhanced fertility in infertile patients with SCH.

Occurrence of thyroxine tablet (Thyradin S(®)) - induced liver dysfunction in a patient with subclinical hypothyroidism

A 54-year-old woman with subclinical hypothyroidism developed liver dysfunction after increasing dose of levothyroxine (L-T4) in tablet form (Thyradin S(®)) from 25μg to 50μg. Viral hepatitis, autoimmune hepatitis and NASH were ruled out with examinations. After cessation of levothyroxine in 50μg tablet form, liver enzymes gradually returned to normal. She was diagnosed levothyroxine-induced liver injury, based on criteria proposed in DDW-J 2004 workshop. Thyradin S(®) powder 0.01% (here in after referred to as L-T4 in powder form) was tried as an alternative, and liver enzymes have remained within normal range. As for Thyradin S(®) tablet, additives are different for each type of levothyroxine sodium content. The difference of additive is whether Fe2O3 is contained or not: it is not included in Thyradin S(®) 50μg tablet and powder form. Although there are two case reports in the Japanese literature and three case reports in the English literature of liver dysfunction suspected due to L-T4, we cannot find past reports about cases of drug induced liver dysfunction due to Fe2O3 free levothyroxine tablet form. This is a rare case report of drug induced liver injury due to Fe2O3 free levothyroxine tablet form, and administration of L-T4 in powder form may be useful for treatment of cases similar to this one.

Characteristic sonographic features of cribriform papillary thyroid carcinoma for differentiation from other thyroid nodules

PURPOSE

The purpose of this paper is to clarify the sonographic features and differential diagnoses of the cribriform variant of papillary thyroid carcinoma (CV-PTC).

METHODS

We retrospectively reviewed 24 nodules obtained from 22 CV-PTC cases. As control groups, we chose 50 cases each of conventional papillary carcinoma (C-PTC), follicular tumor, and nodular goiter.

RESULTS

All of the cases were young women aged 35 years or younger. Serum thyroglobulin levels were normal or slightly elevated. The incidences of smooth or focal jagged margin, hypoechoic nodule, lateral shadow, posterior acoustic enhancement, poor marginal and internal vascularity, and no microcalcification were 100, 100, 91.7, 95.8, 100, and 95.8 %, respectively. The sensitivity and specificity of the requirement were 87.5 and 92.5 %, respectively. Sonographic findings of CV-PTC were similar to those of follicular tumor or nodular goiter rather than C-PTC.

CONCLUSION

The criteria for suspecting CV-PTC we proposed provided high sensitivity and specificity. We should be aware that the sonographic findings of CV-PTC are similar to those of follicular tumor or nodular goiter rather than C-PTC. Clinical findings including gender, age, and serum thyroglobulin level may provide us with useful information.

Cytological characteristics of papillary thyroid carcinoma on LBC specimens, compared with conventional specimens

BACKGROUND

The cytological findings in conventional specimens (C-S) and liquid-based cytology specimens (LBC-S) are not quite same. The aim of this article is to clarify the cytological findings of papillary thyroid carcinoma (PTC) characteristic of LBC-S.

METHODS

Out of 5,971 cases diagnosed in a single institution from March to September in 2012, 161 PTC cases with both C-S and LBC-S were reviewed. Additionally, we compared the findings with those in LBC-S of 55 adenomatous or hyperplastic nodule (AN) and 21 follicular neoplasm (FN) cases.

RESULTS

Compared to C-S, the incidences of trabecular and hobnail patterns, collagenous stroma, naked capillaries, intercellular spaces, convoluted nuclei, eosinophilic nucleoli, and perinucleolar halo were increased. Pale nuclei were observed in only one of 161 PTC cases. Specificity of convoluted nuclei and perinucleolar halo were 97.4% and 96.1%, respectively.

CONCLUSION

Convoluted nuclei and perinucleolar halo might become a new indicator of PTC in LBC-S. Contrarily, we should be aware that pale nuclei are rarely observed in LBC-S.

Differentiation of postpartum Graves' thyrotoxicosis from postpartum destructive thyrotoxicosis using antithyrotropin receptor antibodies and thyroid blood flow

BACKGROUND

Postpartum thyroid dysfunction occurs in approximately 5-10% of women in the general population within one year of delivery. Differentiation of postpartum Graves' thyrotoxicosis (PPGr) from postpartum destructive thyrotoxicosis (PPDT) is essential because of the difference in treatment measures between the two. However, it is sometimes difficult because radioactive iodine uptake is contraindicated when patients are lactating. We examined the usefulness of determining the time of onset postpartum and measurement of antithyrotropin (anti-TSH) receptor antibodies and thyroid blood flow.

METHODS

Forty-two patients with newly developed thyrotoxicosis after delivery were examined: 18 had Graves' disease and 24 had destructive thyrotoxicosis. Serum free thyroxine (fT4), free triiodothyronine (fT3), and TSH were measured by chemiluminescent immunoassays. Anti-TSH receptor antibodies (TRAb), antithyroglobulin antibodies (TgAb), and antithyroid peroxidase antibodies (TPOAb) were measured by the Elecsys electrochemiluminescence immunoassay. Thyroid volume and blood flow (TBF) were measured quantitatively by color flow Doppler ultrasonography.

RESULTS

Onset of thyrotoxicosis was distributed from 2 to 12 months postpartum. Twelve (85.7%) of 14 patients who developed thyrotoxicosis at three months or earlier after delivery had PPDT. On the other hand, all 11 patients who developed thyrotoxicosis at 6.5 months or later had PPGr. All patients with PPGr had positive TRAb (14.9±14.9 IU/L, mean±standard deviation (SD)) and all patients with PPDT had negative TRAb (0.1±0.3 IU/L, p<0.0001). Fifteen (83.3%) of 18 PPGr patients had high TBF of more than 4.0% (8.9±4.4), and all PPDT patients had low TBF of <4.0% (1.6±1.0, p<0.0001). The fT3/fT4 ratio was higher in PPGr (64.0±23.9) than in PPDT (38.9±13.1, p<0.0002), but absolute values overlapped between the two.

CONCLUSION

Early onset of thyrotoxicosis postpartum was associated mainly with PPDT, and a late onset was suggestive of PPGr. Positive TRAb and high TBF >4.0% are indicators of postpartum onset of Graves' disease.

Prevalence of thyrotropin receptor germline mutations and clinical courses in 89 hyperthyroid patients with diffuse goiter and negative anti-thyrotropin receptor antibodies

BACKGROUND

We studied the frequency of thyrotropin (TSH) receptor mutations in hyperthyroid patients with diffuse goiter and negative TSH receptor antibodies (TRAb), and the clinical pictures of the hyperthyroid patients in the presence and absence of mutations.

PATIENTS AND METHODS

From 2003 through 2012, 89 hyperthyroid patients with diffuse goiter and negative TRAb based on a second- or third-generation assay underwent sequence analysis of the TSH receptor gene from peripheral leukocytes. The outcome of hyperthyroidism in patients with a TSH receptor mutation and their affected family members was compared with that in patients without any mutation after a 1-10-year follow-up.

RESULTS

Germline mutations of the TSH receptor occurred in 4 of the 89 patients (4.5%), including 3 definitive constitutively activating mutations (L512Q, E575K, and D617Y). The main difference in the clinical outcome of hyperthyroidism was that no patients with a TSH receptor mutation achieved euthyroidism throughout the follow-up, while 23.5% of patients without any mutation entered remission. The progression from subclinical to overt hyperthyroidism was not significantly different between patients with or without a mutation. Meanwhile, 10.3% of TRAb-negative patients without any TSH receptor mutation developed TRAb-positive Graves' hyperthyroidism during the follow-up.

CONCLUSIONS

The prevalence of nonautoimmune hyperthyroidism with TSH receptor mutations is lower than that of latent Graves' disease in TRAb-negative patients with hyperthyroidism. However, all affected patients with a TSH receptor mutation showed persistent hyperthyroidism regardless of subclinical or overt hyperthyroidism throughout the follow-up.

Papillary thyroid microcarcinoma might progress during pregnancy

BACKGROUND

Papillary thyroid cancer occasionally occurs in women of childbearing age. As papillary thyroid microcarcinoma (PTMC) rarely grows or becomes clinically apparent, observation without surgery is an appropriate strategy for patients with low-risk PTMC. Human chorionic gonadotropin possesses weak thyroid-stimulating activity. The aim of this study was to assess the effect of pregnancy on PTMC.

METHODS

We studied 9 patients with PTMC who became pregnant between 2005 and 2011. Twenty-seven age-matched nonpregnant female PTMC patients from a database we used in our previous report served as controls. Tumor enlargement was defined as an increase in the diameter of the tumor of 3 mm or more.

RESULTS

PTMC enlargement occurred in 44.4% (4/9 patients) of the pregnant subjects, whereas it occurred only in 11.1% (3/27 patients) of the controls (p=0.0497). Three of the pregnant patients who exhibited tumor enlargement underwent surgery after delivery. No relationship was detected between the changes in the serum thyroglobulin level, the serum thyrotropin level, and tumor size during pregnancy. Immunohistochemical examinations did not detect the estrogen receptor in the tumors of the three patients who underwent surgery.

CONCLUSIONS

This study is an initial report indicating that the risk of PTMC enlargement might increase during pregnancy. PTMC should be carefully followed-up for possible disease aggravation during pregnancy. Even if a PTMC enlarges during pregnancy, the patient's prognosis will probably not worsen.

Papillary thyroid carcinoma with honeycomb-like multiple small cysts: characteristic features on ultrasonography

BACKGROUND

Thyroid nodules with cystic content or mixed sponge-like aspect on ultrasonography and a concordant cytology are strongly predictive of benignity.

OBJECTIVES

We present 8 patients with honeycomb-like papillary thyroid carcinoma with multiple small cysts on ultrasonography.

METHODS

The patients were 6 women and 2 men aged between 30 and 57 years. The tumors of these patients showed honeycomb-like multiple small cysts that were aggregated in some area of the thyroid gland on ultrasonography. Histopathological examination indicated a well-differentiated type of papillary thyroid carcinoma with multiple small cysts and a small solid lesion. The cysts were lined with papillary carcinoma cells, and normal thyroid tissue lay between the cysts.

RESULTS

There is a peculiar type of papillary thyroid carcinoma that histopathologically shows honeycomb-like multiple small cysts in the thyroid gland. Ultrasonography can be used to identify characteristic features of honeycomb-like multiple small cysts in the thyroid gland in such patients.

CONCLUSIONS

One should be aware of this peculiar type of papillary thyroid carcinoma with honeycomb-like multiple small cysts on ultrasonography, although thyroid nodules with cystic lesions are generally regarded as benign in clinical management.

Use of color Doppler ultrasonography to measure thyroid blood flow and differentiate graves' disease from painless thyroiditis

BACKGROUNDS

Color Doppler ultrasonography (CDU) has not yet been established as a method to investigate the pathogenesis of thyrotoxicosis.

OBJECTIVES

Our first objective was to determine whether the measurement of peak systolic blood-flow velocity in the superior thyroid artery (STV) and thyroid tissue blood flow (TBF) using CDU could differentiate Graves' disease (GD) from painless thyroiditis (PT). The second objective was to examine the factors mediating increased blood flow to the thyroid gland in GD.

METHODS

Recruited patients had untreated GD or PT and visited the Department of Internal Medicine (I), Osaka Medical College, between April 1, 2006 and May 31, 2010. Age, gender, blood pressure, pulse rate, thyroid-stimulating hormone, free thyroxine, tri-iodothyronine, TSH receptor antibody and thyroid volume were evaluated in patients. In addition, bilateral measurements of STV, TBF and peak systolic velocity in the common carotid artery (CCV) were also performed. TBF was quantified by calculating the ratio of blood-flow pixels to total pixels in the region of interest using sagittal section images of the thyroid gland. Receiver-operating characteristic curve analysis was performed to determine the ability of STV and TBF measurements to differentiate GD from PT.

RESULTS

For the average of STV measured on both sides, the area under the receiver-operating characteristic curve (AUC) was 0.956. For the average of TBF measured on both sides, the AUC was 0.920. At an average STV cut-off value of 43 cm/s, the sensitivity to discriminate GD from PT was 0.87 and the specificity was 1.00. At an average TBF cut-off value of 3.8%, the sensitivity was 0.71 and the specificity was 1.00. In the GD group, neither blood pressure nor pulse rate correlated with the average STV or TBF. Moreover, there was no correlation between STV and CCV or between TBF and CCV on either side. However, STV was correlated with TBF (right side: R = 0.47; left side: R = 0.52).

CONCLUSIONS

The results demonstrate that STV and TBF are useful for differentiating GD from PT. Furthermore, the increased STV and TBF found in GD are not related to hyperthyroidism-induced increases in systolic blood pressure, pulse rate or CCV.

Initial treatment with 15 mg of prednisolone daily is sufficient for most patients with subacute thyroiditis in Japan

BACKGROUND

Oral glucocorticoids are administered in moderate and severe cases of subacute thyroiditis (SAT), providing dramatic relief from pain and fever. However, there have been no reports regarding the optimal dose of prednisolone (PSL) for treatment of SAT. In this study, we used 15 mg/day of PSL as the initial dosage and tapered it by 5 mg every 2 weeks. We assessed the effectiveness of this treatment protocol.

METHODS

We examined 384 consecutive and untreated patients with SAT who visited our thyroid clinic between February 2005 and December 2008. We excluded patients who did not fit our protocol, and the final number of subjects was 219. When patients complained of pain in their neck or C-reactive protein (CRP) was still high, physicians were able to extend the tapering of the dose of PSL or increase it at 2-week intervals. The endpoint of the study was the duration of the PSL medication. We also compared the severity of thyrotoxicosis and rate of hypothyroidism after SAT between the short medication group (patients who recovered within 6 weeks) and long medication group (patients who recovered in 12 weeks or more).

RESULTS

The number of patients whose thyroiditis improved within 6 weeks and did not recur was 113 (51.6%), and 61 (27.9%) improved within 7 to 8 weeks and did not have a recurrence. The longest duration was 40 weeks. Seven patients (3.2%) needed increases in the dosage of PSL. Thyroid hormone (free thyroxine and free triiodothyronine) levels measured at the initial visit in the short medication group were significantly higher than those in the long medication group (p<0.05). Serum CRP, male-to-female ratio, body weight, and age showed no differences between the two groups. There were no differences in the rate of hypothyroidism after SAT between the two groups (p=0.0632).

CONCLUSIONS

The treatment protocol that we employed had 15 mg/day of PSL as the initial dosage for the treatment of SAT, with tapering by 5 mg every 2 weeks, and was effective and safe for Japanese patients. However, 20% of patients with SAT needed longer than 8 weeks to recover from the inflammation.

Effect of L-thyroxine replacement on apolipoprotein B-48 in overt and subclinical hypothyroid patients

Apolipoprotein B-48 (ApoB-48) is a constituent of chylomicrons and chylomicron remnants, and is thought to be one of the risk factors for atherosclerosis. We evaluated the effect of L-thyroxine (L-T(4)) replacement on serum ApoB-48 levels in patients with primary hypothyroidism. Eighteen patients with overt hypothyroidism (OH) and 18 patients with subclinical hypothyroidism (SH) participated in the study. The lipid profiles, including ApoB-48, were measured in patients with hypothyroidism before and 3 months after L-T(4) replacement. After L-T(4) replacement, the serum concentrations of all lipoproteins, exclusive of lipoprotein(a) (Lp(a)), were significantly decreased in patients with OH. In patents with SH, the serum levels of total cholesterol (TC), non-high-density lipoprotein cholesterol (non-HDL-C), remnant-like particle cholesterol (RLP-C), apolipoprotein B (ApoB), and ApoB-48 decreased significantly after L-T(4) replacement. The serum levels of triglycerides (TG), HDL-C, low-density lipoprotein cholesterol (LDL-C), apolipoprotein A1 (ApoA-1), and Lp(a) did not change significantly. In all 36 patients, the reduction in the ApoB-48 levels correlated significantly with the reduction in TSH levels (r = 0.39, P<0.05). This study showed clearly that L-T(4) replacement might reduce serum levels of ApoB-48 in both OH and SH patients. Such altered serum levels of ApoB-48 in patients with OH and SH may be related to the disturbed metabolism of chylomicron remnants in patients with hypothyroidism.

[Concept and management of postpartum thyroid dysfunction]

Postpartum thyroid dysfunction is found in 5-10% of women within one year after delivery. Dysfunction is developed from subclinical autoimmune thyroiditis through immune rebound mechanism and divided into 5 types. Most frequent one is destructive thyrotoxicosis, named as postpartum thyroiditis, which occur in early postpartum period and usually followed by transient hypothyroidism. Some of them progress into permanent hypothyroidism. Graves' disease is also developed mainly after 4 months postpartum and found in one out of 200 postpartum women in general population. Treatment of this dysfunction is principally the same as ordinal thyroid disease except for transient hypothyroidism.

TSH-suppressive doses of levothyroxine are required to achieve preoperative native serum triiodothyronine levels in patients who have undergone total thyroidectomy

OBJECTIVE

Thyroidal production of triiodothyronine (T(3)) is absent in patients who have undergone total thyroidectomy. Therefore, relative T(3) deficiency may occur during postoperative levothyroxine (L-T(4)) therapy. The objective of this study was to evaluate how the individual serum T(3) level changes between preoperative native thyroid function and postoperative L-T(4) therapy.

METHODS

We retrospectively studied 135 consecutive patients with papillary thyroid carcinoma, who underwent total thyroidectomy. Serum free T(4) (FT(4)), free T(3) (FT(3)), and TSH levels measured preoperatively were compared with those levels measured on postoperative L-T(4) therapy.

RESULTS

serum tsh levels during postoperative L-T(4) therapy were significantly decreased compared with native TSH levels (P<0.001). serum FT(4) levels were significantly increased (P<0.001). Serum FT(3) levels were significantly decreased (P=0.029). We divided the patients into four groups according to postoperative serum TSH levels: strongly suppressed (less than one-tenth of the lower limit); moderately suppressed (between one-tenth of the lower limit and the lower limit); normal limit; and more than upper limit. Patients with strongly suppressed TSH levels had serum FT(3) levels significantly higher than the native levels (P<0.001). Patients with moderately suppressed TSH levels had serum FT(3) levels equivalent to the native levels (P=0.51), and patients with normal TSH levels had significantly lower serum FT(3) levels (P<0.001).

CONCLUSIONS

Serum FT(3) levels during postoperative L-T(4) therapy were equivalent to the preoperative levels in patients with moderately suppressed TSH levels. Our study indicated that a moderately TSH-suppressive dose of L-T(4) is required to achieve the preoperative native serum T(3) levels in postoperative L-T(4) therapy.

Management of thyroid dysfunction during pregnancy and postpartum: an Endocrine Society clinical practice guideline

OBJECTIVE

The aim was to update the guidelines for the management of thyroid dysfunction during pregnancy and postpartum published previously in 2007. A summary of changes between the 2007 and 2012 version is identified in the Supplemental Data (published on The Endocrine Society's Journals Online web site at http://jcem.endojournals.org).

EVIDENCE

This evidence-based guideline was developed according to the U.S. Preventive Service Task Force, grading items level A, B, C, D, or I, on the basis of the strength of evidence and magnitude of net benefit (benefits minus harms) as well as the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system to describe both the strength of recommendations and the quality of evidence.

CONSENSUS PROCESS

The guideline was developed through a series of e-mails, conference calls, and one face-to-face meeting. An initial draft was prepared by the Task Force, with the help of a medical writer, and reviewed and commented on by members of The Endocrine Society, Asia and Oceania Thyroid Association, and the Latin American Thyroid Society. A second draft was reviewed and approved by The Endocrine Society Council. At each stage of review, the Task Force received written comments and incorporated substantive changes.

CONCLUSIONS

Practice guidelines are presented for diagnosis and treatment of patients with thyroid-related medical issues just before and during pregnancy and in the postpartum interval. These include evidence-based approaches to assessing the cause of the condition, treating it, and managing hypothyroidism, hyperthyroidism, gestational hyperthyroidism, thyroid autoimmunity, thyroid tumors, iodine nutrition, postpartum thyroiditis, and screening for thyroid disease. Indications and side effects of therapeutic agents used in treatment are also presented.

Histopathological diagnoses of "accessory" thyroid nodules diagnosed as benign by fine-needle aspiration cytology and ultrasonography

BACKGROUND

Patients who have thyroidectomies for thyroid nodules that are suspected of being malignant, called here "main nodules," occasionally have second nodules, called here "accessory nodules" that are evaluated by ultrasonography (US) and fine-needle aspiration cytology (FNAC). Most accessory nodules are diagnosed as benign based on preoperative US and FNAC. To evaluate the accuracy of US and FNAC for a group of nodules which were likely to be mostly benign we evaluated procedures to diagnose accessory nodules.

PATIENTS AND METHODS

In a total of 643 patients who underwent thyroidectomy for their main nodules, 866 accessory nodules were evaluated by US and/or FNAC preoperatively. All were evaluated by histopathological examination postoperatively. Of the 866 accessory nodules, 501 were evaluated by US only and 365 were evaluated by US and FNAC.

RESULTS

While the 363 accessory nodules were diagnosed as malignant by histopathology, 235 nodules were malignant by US and histopathology and 115 nodules were malignant by FNAC and histopathology. Among the accessory nodules that were diagnosed as benign by histopathology, 7.2% were malignant by US, and 4.4% were malignant by FNAC. Among the accessory nodules that were diagnosed as benign by FNAC, 15.0% were malignant by histopathology. This was a significantly higher percentage than the value of 6.2% for the accessory nodules diagnosed as benign by US but malignant by histopathology. Accessory nodules with a benign cytology on FNAC that were malignant were significantly smaller than those with a benign cytology and histopathology. Among the 126 accessory nodules that were read as benign by both US and FNAC, only one (0.8%) was diagnosed as papillary thyroid carcinoma by histopathology.

CONCLUSION

These data suggest that diagnostic accuracy of benign nodules based on both US and cytological evaluation was supported by the evidence of high-level histopathological compatibility in accessory nodules. FNAC and US have a low but not negligible false-negative diagnostic rate. When FNAC is combined with US the false-negative rate is probably very low.

Deletion of thyrotropin receptor residue Asp403 in a hyperfunctioning thyroid nodule provides insight into the role of the ectodomain in ligand-induced receptor activation

Somatic mutations of the TSH receptor (TSHR) gene are the main cause of autonomously functioning thyroid nodules. Except for mutations in ectodomain residue S281, all of the numerous reported activating mutations are in the TSHR membrane-spanning region. Here, we describe a patient with a toxic adenoma with a novel heterozygous somatic mutation caused by deletion of ectodomain residue Asp403 (Del-D403). Subsequent in vitro functional studies of the Del-D403 TSHR mutation demonstrated greatly increased ligand-independent constitutive activity, 8-fold above that of the wild-type TSHR. TSH stimulation had little further effect, indicating that the mutation produced near maximal activation of the receptor. In summary, we report only the second TSHR ectodomain activating mutation (and the first ectodomain deletion mutation) responsible for development of a thyroid toxic adenoma. Because Del-D403 causes near maximal activation, our finding provides novel insight into TSHR structure and function; residue D403 is more likely to be involved in the ligand-mediated activating pathway than in the ectodomain inverse agonist property.

Tumor thrombus of thyroid malignancies in veins: importance of detection by ultrasonography

BACKGROUND

Tumor thrombus in the thyroid vein or the internal jugular vein may be caused by thyroid malignancies. Therefore, a tumor thrombus is very suspicious for malignancy. Total thyroidectomy should be performed in such patients if there is a primary thyroid tumor, and a high probability of pulmonary metastasis seems likely as there is direct exposure of malignant cells to the circulation. Our study was performed to determine whether ultrasonography is an effective preoperative modality to detect tumor thrombi of thyroid malignancies and whether tumor thrombi are associated with pulmonary metastases.

METHODS

Between 2004 and 2009, all thyroid surgery patients at Kuma Hospital had preoperative neck ultrasonography to look for tumor thrombi in the thyroid veins and the internal jugular veins as well as thyroid masses and abnormal lymph nodes. We looked for solid masses with an echogenic "tongue" in the internal jugular vein and masses with a projection from thyroid tumor to the thyroid vein on grayscale ultrasonography. We also used Doppler ultrasonography to look for the absence of blood flow.

RESULTS

Among 7754 patients who had thyroid surgery, there were 9 patients with tumor thrombi. In seven of the patients, tumor thrombi were detected by preoperative ultrasound, and in the remaining two patients, tumor thrombi were detected during surgery. Tumor thrombi were identified in the internal jugular vein in six patients and in the thyroid vein in three patients. Pulmonary metastases were present in three patients (50% of the patients with thyroid carcinoma). The patients with tumor thrombi were more likely (33.3%) to have pulmonary metastasis than those without (0.9%) tumor thrombi (p < 0.0001). In four patients with papillary carcinoma, projection-like lesions of irregularly shaped tumors were misdiagnosed to be tumor thrombi in the thyroid veins on preoperative ultrasound. These four patients did not have pulmonary metastases.

CONCLUSIONS

The preoperative detection of a tumor thrombus on ultrasonography has important clinical significance. Therefore, preoperative neck ultrasound in patients with thyroid masses should attempt to determine whether there are signs of tumor thrombi as well as to characterize the nature and location of abnormal thyroid and extrathyroid masses.

Pathologic features of polycystic thyroid disease: comparison with benign nodular goiter

Polycystic thyroid disease (PCTD) is characterized by multiple thyroid cysts detected by ultrasonography, the absence of thyroid autoantibodies, and susceptibility to the development of hypothyroidism due to a high iodine intake. It is necessary to obtain histopathological information on PCTD in order to clarify the cause of hypothyroidism. We retrospectively reviewed three patients with PCTD and small papillary thyroid cancer who underwent thyroidectomy. We observed the thyroid tissues pathologically in areas with and without multiple cysts, and compared them with those of multinodular goiter with cysts. In the patients with PCTD, there were multiple enlarged follicles that resembled enlarged normal follicles and differed from those found in multinodular goiter in terms of their shape. Huge follicles corresponded to the cysts that were detected by ultrasonography. Each follicle contained colloid. Follicular cells in enlarged follicles comprised low cuboidal epithelium that appeared normal. These findings were common in the 3 patients with PCTD. In Conclusion the PCTD patients had multiple enlarged follicles that seemed to decrease the total number of follicular cells, and may be a cause of hypothyroidism. We believe that PCTD is a new entity of thyroid disease based on the pathological findings.

A solid thyroid benign nodule that showed a significant decrease in size and ultrasonographic findings mimicking papillary carcinoma during 16-year follow-up

Recent advances in ultrasonography and fine needle aspiration biopsy (FNAB) have facilitated accurate diagnosis of thyroid carcinomas that require treatment. However, we often encounter nodules evaluated as malignant on ultrasonography but diagnosed as benign on cytology, for which the optimal treatment strategy remains uncertain. A 28-year-old female had solitary and solid thyroid nodule measuring 6 cm in maximal diameter in February 1994. The lesion was cytologically diagnosed as benign. From September 1998, the nodule spontaneously decreased in size but ultrasonographic findings suspicious of malignancy such as peripheral and intra-tumoral calcification, low internal echo and irregular border gradually appeared. In July 2010, the volume of her nodule showed 97% decrease but was evaluated as papillary carcinoma on ultrasonography. FNAB was performed again and the nodule was diagnosed as benign. When we encounter a nodule showing ultrasonographic findings suggestive of malignancy with negative cytology, we should consider the possibility of a benign nodule degenerating over time.

Serum calcitonin levels with calcium loading tests before and after total thyroidectomy in patients with thyroid diseases other than medullary thyroid carcinoma

Calcitonin is a very sensitive tumor marker of medullary thyroid carcinoma (MTC). Patients with MTC have usually very high levels of serum calcitonin that can be used to diagnose the disease. In order to improve diagnostic sensitivity in family members with small MTCs or to evaluate postoperative biochemical cure status, measurement of calcitonin stimulated with combined intravenous calcium gluconate and pentagastrin has been widely adopted; however, gastrin has become unavailable. Currently, a provocative test using only calcium gluconate is performed; however, the standard values for this test have not been reported. We therefore conducted calcium gluconate stimulation tests in 20 patients before and after total thyroidectomy for thyroid diseases other than MTC. Preoperatively, the mean basal calcitonin level was 24.1 pg/mL and increased to 46.9pg/mL after calcium infusion. The ratio of the peak calcitonin level to the basal value ranged from 1- to 5.23-fold, with a mean of 1.94. The ratio was higher than 3-fold in 3 patients. In 2 patients, peak calcitonin levels exceeded 100 pg/mL. Postoperatively, the mean basal level slightly decreased to 21.15pg/mL and the response to calcium stimulation markedly decreased, with the mean ratio decreasing to 1.1-fold (range, 0.86- to 1.73-fold, maximum peak level, 33 pg/mL). Thus, some subjects without MTC show response to the calcium stimulation test up to 5.24 times the ratio and a peak value of 160 pg/mL, suggesting the requirement for judicious judgment for the early diagnosis of MTC in family members; however, after total thyroidectomy, none of the subjects showed an increase of more than 2-fold or a peak value of 33pg/mL, suggesting that responses greater than 2-fold after MTC surgery might be abnormal, indicating the presence of residual tumor.

Type 1 and type 2 iodothyronine deiodinases in the thyroid gland of patients with 3,5,3'-triiodothyronine-predominant Graves' disease

OBJECTIVE

3,5,3'-triiodothyronine-predominant Graves' disease (T(3)-P-GD) is characterized by a persistently high serum T(3) level and normal or even lower serum thyroxine (T(4)) level during antithyroid drug therapy. The source of this high serum T(3) level has not been clarified. Our objective was to evaluate the contribution of type 1 and type 2 iodothyronine deiodinase (D1 (or DIO1) and D2 (or DIO2) respectively) in the thyroid gland to the high serum T(3) level in T(3)-P-GD.

METHODS

We measured the activity and mRNA level of both D1 and D2 in the thyroid tissues of patients with T(3)-P-GD (n=13) and common-type GD (CT-GD) (n=18) who had been treated with methimazole up until thyroidectomy.

RESULTS

Thyroidal D1 activity in patients with T(3)-P-GD (492.7±201.3 pmol/mg prot per h) was significantly higher (P<0.05) than that in patients with CT-GD (320.7±151.9 pmol/mg prot per h). On the other hand, thyroidal D2 activity in patients with T(3)-P-GD (823.9±596.4 fmol/mg prot per h) was markedly higher (P<0.005) than that in patients with CT-GD (194.8±131.6 fmol/mg prot per h). There was a significant correlation between the thyroidal D1 activity in patients with T(3)-P-GD and CT-GD and the serum FT(3)-to-FT(4) ratio (r=0.370, P<0.05). Moreover, there was a strong correlation between the thyroidal D2 activity in those patients and the serum FT(3)-to-FT(4) ratio (r=0.676, P<0.001).

CONCLUSIONS

Our results suggest that the increment of thyroidal deiodinase activity, namely D1 and especially D2 activities, may be responsible for the higher serum FT(3)-to-FT(4) ratio in T(3)-P-GD.

Subclinical nonautoimmune hyperthyroidism in a family segregates with a thyrotropin receptor mutation with weakly increased constitutive activity

BACKGROUND

Subclinical hyperthyroidism is usually associated with Graves' disease or toxic nodular goiter. Here we report a family with hereditary subclinical hyperthyroidism caused by a constitutively activating germline mutation of the thyrotropin receptor (TSHR) gene.

METHODS

The proband was a 64-year-old Japanese woman who presented with a thyroid nodule and was found to be euthyroid with a suppressed serum TSH. The nodule was not hot. Although antibodies to thyroid peroxidase and thyroglobulin antibodies were present, TSHR antibodies were not detected by TSH-binding inhibition or by bioassay. Two of her middle-aged sons, but not her daughter, also had subclinical hyperthyroidism without TSHR antibodies. Without therapy, the clinical condition of the affected individuals remained unchanged over 3 years without development of overt hyperthyroidism.

RESULTS

A novel heterozygous TSHR point mutation causing a glutamic acid to lysine substitution at codon 575 (E575K) in the second extracellular loop was detected in the three family members with subclinical hyperthyroidism, but was absent in her one daughter with normal thyroid function. In vitro functional studies of the E575K TSHR mutation demonstrated a weak, but significant, increase in constitutive activation of the cAMP pathway.

CONCLUSION

Although hereditary nonautoimmune overt hyperthyroidism is very rare, TSHR activating mutations as a cause of subclinical hyperthyroidism may be more common and should be considered in the differential diagnosis, especially if familial.

The prevalence of polycystic thyroid disease in hypothyroid patients with negative thyroid autoantibodies

BACKGROUND

We previously reported that multiple thyroid cysts may be a cause of hypothyroidism in patients with a relatively high iodine intake and we termed it polycystic thyroid disease (PCTD). The aim of this study was to investigate the prevalence of PCTD in patients who visited our thyroid center. We hypothesized that patients with PCTD are not rare in a region with a high iodine intake.

METHODS

We retrospectively studied the cause of hypothyroidism based on medical histories and ultrasonography in new patients to our hospital from April 2008 to March 2009 whose serum tests for antithyroglobulin antibodies (TgAb) and thyroid peroxidase antibodies (TPOAb) were negative. Serum thyroid hormones, thyrotropin (TSH), TgAb, and TPOAb were measured in 8243 patients. Patients with four or more thyroid cysts, negative tests for TgAb and TPOAb, no evidence for thyroid diseases other than their thyroid cysts, and no exposure to thyroid-perturbing influences were defined as having PCTD.

RESULTS

Three hundred seven patients had overt hypothyroidism (TSH level above 10.0 μU/mL and free thyroxine level below 0.7 ng/dL), of whom 71 patients were both TgAb and TPOAb negative. There were 546 patients with subclinical hypothyroidism (TSH level above 5.0 μU/mL and normal free thyroxine), of whom 193 patients were both TgAb and TPOAb negative. There were 24 patients with overt hypothyroidism and PCTD, accounting for 7.8% (24/307) of all causes of overt hypothyroidism. There were 42 patients with subclinical hypothyroidism and PCTD, accounting for 7.7% (42/543) of all causes of subclinical hypothyroidism. PCTD was more common among elderly people than young people.

CONCLUSIONS

PCTD appears to be a minor but not negligible cause of hypothyroidism, at least in iodine-rich regions. PCTD with hypothyroidism may have been misdiagnosed as thyroid antibody-negative Hashimoto's thyroiditis in many reports.

Thyroid ultrasonography

BACKGROUND

The recent prevalence of ultrasonography (US) has facilitated the early detection and qualitative evaluation of thyroid nodules. Furthermore, novel technical developments are extending the application range of US for other thyroid diseases.

METHODS

The use of US to differentiate between thyroid carcinoma and benign nodule, between a metastatic lymph node and a reactive node, between thyroid lymphoma and chronic thyroiditis, and between destruction-induced thyrotoxicosis and Graves' disease is introduced.

RESULTS

Classification systems for thyroid nodule have shown high diagnostic accuracy for thyroid carcinomas except follicular carcinoma. US diagnosis of lymph node metastasis showed high specificity but low sensitivity. Patients who were suspected of thyroid lymphoma based on US findings should undergo incisional biopsy or thyroidectomy for diagnosis of the histologic type if fine-needle aspiration biopsy findings suggest lymphoma. Patients should be carefully followed even if they were diagnosed as negative based on cytologic findings. Measurement of thyroid blood flow is helpful for diagnosing destruction-induced thyrotoxicosis, such as painless thyroiditis, by distinguishing the lesion from Graves' disease.

CONCLUSIONS

Ultrasonography is useful for diagnosing various thyroid diseases, including thyroid carcinoma. The remaining issue to be resolved is the diagnosis of follicular carcinoma. Trials using novel techniques to differentiate these lesions are expected.