New subgrouping of small thyroid carcinomas

Early Quantification of Salivary Gland Function after Radioiodine Therapy

Purpose of the Study:

Radioiodine (I-131) is used as an effective noninvasive treatment for thyroid malignancies. Salivary gland is one of the most affected nontarget organs. The present study aims to perform early quantification of salivary gland function after I-131 therapy (RIT) for thyroid cancer considering I-131 down-scatter in the Tc-99m window.

Materials and Methods:

A total of 20 patients (6 males and 14 females) with differentiated thyroid carcinoma were enrolled in the study. Baseline dynamic salivary scintigraphy was performed in all patients using 185–370 MBq (5–10 mCi) Tc-99m pertechnetate. Posttherapy, salivary scintigraphy was performed 10–25 days after RIT in the range of 1.85–7.4 GBq (50–200 mCi). Time–activity curves obtained from the pre- and posttherapy dynamic salivary scintigraphy were used for semi-quantitative analysis. Uptake ratio (UR), ejection fraction (EF%), and maximum accumulation (MA%) were calculated by drawing regions of interest of individual parotid and submandibular glands over a composite image, after correcting for down-scatter from I-131 in the Tc-99m window. A paired t-test was used for comparison of the parameters obtained.

Results:

Significant changes were observed in UR and EF% of both parotid and submandibular glands (P < 0.05). No significant changes were found in the value of MA% of left parotid gland and both submandibular glands in the posttherapy scans in comparison to pretherapy scans (P > 0.05). However, significant difference was observed in the MA% of the right parotid gland (P = 0.025).

Conclusion:

Salivary gland function was found to deteriorate after RIT, with the parotid glands affected more than the submandibular glands.

Cytological examination of the thyroid in children and adolescents after the Fukushima Nuclear Power Plant accident: the Fukushima Health Management Survey

The Fukushima Daiichi Nuclear Power Plant accident occurred on March 11 2011, following the Great East Japan Earthquake and tsunami. Radioactive materials, including I-131, were released into the environment after the accident. Shortly after, the prefectural government initiated the Fukushima Health Management Survey for monitoring the long-term health conditions of the residents of Fukushima Prefecture. In the survey, thyroid ultrasonography was scheduled for all people aged 18 years or younger who were living in Fukushima Prefecture at the time of disaster. The total number of examinees was approximately 370,000 in the Preliminary Baseline Survey (PBLS), and 380,000 in the first Full-scale Survey (FSS). First, thyroid ultrasonography was performed as the Primary Examination. When a thyroid nodule that meets the fine needle aspiration cytology (FNAC) guideline is detected, thyroid FNAC is performed. By the end of June 2017, the cytological specimens of 187 examinees had been interpreted as Malignant or Suspicious for Malignancy (SFM). In this article, the cytological results of whole categories are presented using the criteria of The Bethesda System for Reporting Thyroid Cytopathology. The total numbers of examinees with SFM or Malignant in PBLS and at the first FSS were 106 (62.0%) and 71 (38.0%), respectively. The data of the cytological results of SFM and Malignant were already reported. However, this is the first report of cytological data from categories other than SFM and Malignant. The results of the current study will contribute to future research into the thyroid conditions of children and adolescents.

Surgical Treatment in Papillary Thyroid Microcarcinoma

Despite the notable increasing incidence of papillary thyroid microcarcinoma (PTMC), the optimal treatment of the patients with PTMC remains controversial. Because of no consensus about its treatment, the suggested treatment varies from active surveillance alone to total thyroidectomy. Although the 2015 revised American Thyroid Association guideline recommends hemithyroidectomy as the first-line treatment, active surveillance has also been discussed and accepted as another approach for the patients with PTMC. However, the same guideline does not recommend fine needle aspiration biopsy for nodules sized <1 cm, even it is suspicious. In such situation, neither active surveillance nor hemithyroidectomy could be discussed, with a lack of objective cytologic data about the nodules sized <1 cm. In this situation, the decision to perform FNAB to the nodules <1 cm in size depends on the performer of the thyroid ultrasonography. In this invited review, we have discussed the diagnosis and prognostic factors for PTMCs. We have also discussed surgical strategies as the accepted the first-line treatment in patients with PTMC.

Papillary thyroid microcarcinoma (Black Ink)

We report a case of a 58-year-old Caucasian woman affected by papillary thyroid microcarcinoma (PTMC) of the left-lobe of the gland with very small size (Ø 0.3 cm). The characteristics with the Diagnostic Imaging using Ultrasonography, ADF (Advanced Dynamic Flow), and fine-needle-aspiration cytology (FNAC) are discussed, comprising a very small micro-focus of radial shape, with markedly hypoechoic echostructure, irregular margins, supplemented by peripheral vessel formation. It acquires an image which appears similar to a brisk visualization of a dark ink stain in the normal thyroid weave. We call such a pattern "Black Ink" with ultrasonographic image and believe consistent with the infiltrating variant of papillary thyroid microcarcinoma if associated with malignant cytology after FNA.

Risk factors associated with intrathyroid extension of thyroid microcarcinomas

PURPOSE

The aims of this study were to investigate the rate of intrathyroid extension of papillary thyroid microcarcinoma (PTMC) in patients operated for benign thyroid disease and to identify independent risk factors associated with it.

METHODS

A retrospective study of 301 patients operated for benign thyroid diseases (hyperthyroid diseases, multinodular goitre, Hashimoto thyroiditis and benign thyroid tumours) was performed at a high-volume endocrine surgery unit of a tertiary referral academic hospital, in a 5-year period. These patients had a PTMC incidentally discovered on definite histopathological findings following total or near-total thyroidectomy. Since distinguishing between intrathyroid extension of PTMC as the result of intrathyroid dissemination or as the result of multicentricity is challenging, we observed them together as multifocality. In statistical analysis, we used standard descriptive statistics and univariate and multivariate logistic regression analysis to determine independent risk factors associated with multifocality.

RESULTS

In our study, there were 85.4% females and 14.6% males with a median age of 54 years. A multinodular goitre (32.5%) was the most common indication for an operation. Most patients (68.4%) had a PTMC that was 5 mm or smaller. The most frequent histological variants of PTMC were the follicular variant (52.8%), followed by the papillary variant (22.6%) and the mixed follicular-papillary variant (18.6%). A multifocal PTMC was present in 26.6% of cases. An independent protective factor for multifocality of PTMC was a thyroid gland that weighed more than 38 g (OR 0.55, 95% CI 0.31-0.97, p = 0.039). Size of PTMC greater than 5 mm was an independent risk factor for a multifocal PTMC (OR 3.26, 95% CI 1.85-5.75, p = 0.000). Finally, the mixed follicular-papillary variant of PTMC represents an independent risk factor for a multifocal PTMC (OR 2.42, 95% CI 1.09-5.36, p = 0.030).

CONCLUSIONS

Intrathyroid extension is present in more than a quarter of PTMCs found in patients operated for benign thyroid disease. Independent risk factors for intrathyroid extension are size of PTMC greater than 5 mm and the mixed follicular-papillary variant of PTMC, while a large thyroid gland is an independent protective factor.

Too Much of a Good Thing: Radioactive Iodine Ablation Use for Micropapillary Thyroid Carcinoma

Radioactive iodine (RAI) is not routinely recommended for the adjuvant treatment of micro-papillary thyroid carcinoma (MPTC). We aimed to report on clinical and pathologic factors associated with the use of RAI in these patients. We queried the Surveillance, Epidemiology, and End Results database for patients who underwent surgery for MPTC (tumor size ≤1 cm) from 1988 to 2009. We excluded patients without a biopsy-proven diagnosis, those diagnosed at autopsy, and patients with documented extra-thyroidal extension. Multivariate logistic regression models predicted the use of RAI based on patient, tumor, and treatment-related factors. We identified 24,076 patients with MPTC that were eligible for study inclusion. Of these, 6,172 (25.6%) received RAI. Lymph node metastases were present in 23.8 per cent of those for whom lymph node status was known. On multivariate analysis, an increasing number of positive nodes, increasing tumor size, Asian race, and male gender predicted the use of RAI. RAI use was less likely in those with advancing age, an increasing number of lymph nodes examined and patients that received less than a total thyroidectomy. Among node-negative patients, Asian race and increasing tumor size predicted the use of RAI. Factors predicting decreased use of RAI were an increasing number of lymph nodes examined, unknown race, less than a total thyroidectomy, and advancing age. A significant number of MPTC patients receive potentially unnecessary RAI.

A favorable tumor size to define papillary thyroid microcarcinoma: an analysis of 1176 consecutive cases

Background

The optimal treatment strategy for papillary thyroid microcarcinoma (PTMC) has remained controversial. The purpose of this study was to provide a new reference value for PTMC to aid the selection of optimal management for minute lesions.

Patients and methods

A pool of 1176 consecutive patients who met the inclusion criteria were ultimately enrolled in this study. The correlation of papillary thyroid carcinoma (PTC) tumor size and lymph node metastasis was analyzed. Receiver operating characteristic curve studies were conducted to identify the reference value by determining the optimal cut-off point of size related to lymph node metastasis. To validate our results, all selected patients were divided into two groups according to the cut-off point and some of the prognostic factors were compared.

Results

A moderate significant correlation was found between the tumor size and the average number of lymph node metastases (r=0.502, P<0.01) and the percentage of lymph node metastasis (r=0.625, P<0.01). The optimal cut-off reference value was 8.5 mm according to the receiver operating characteristic curves. Significant differences were observed for PTC prognostic factors, for example, extrathyroidal extension, multifocality, pathologic (p) N+ stage, occult metastasis in clinical (c) N− stage, radioactive iodine ablation, and recurrence between the two groups.

Conclusion

Due to more aggressive behavior and poorer prognosis in larger tumor size (>8.5 mm), a tumor size ≤8.5 mm in diameter may be favorable to discriminate PTMC from PTC and aid the selection of optimal management.

Fine-needle aspirates of thyroid microcarcinoma

INTRODUCTION

Widespread use of ultrasound allows for detection of smaller thyroid nodules and preoperative evaluation with fine-needle aspiration (FNA). Both incidental and non-incidental microcarcinoma can be found, leading to uncertainty with clinical management.

MATERIALS AND METHODS

A retrospective analysis of thyroid FNAs performed at our institution was conducted for the 5-year period from 2010 to 2014. Aspirates were categorized using the Bethesda System for Reporting Thyroid Cytopathology. Cytologic diagnoses were then correlated with final histopathology. Among samples with malignancy on surgical resection, nodules were stratified by size.

RESULTS

A total of 2531 thyroid FNAs were identified; 587 samples had histologic correlation, and 259 malignancies were reported. They were separated into nodules >1 cm (n = 144, 56%) and ≤1 cm (n = 115, 44%). Microcarcinoma was further subdivided into incidental (size ≤0.5 cm, n = 55, 48%) and non-incidental (size >0.5 cm and ≤1 cm, n = 60, 52%). The preoperative cytologic diagnoses for incidental microcarcinoma were: benign (B, n = 11, 20%), follicular lesion of undetermined significance (FLUS, n = 15, 27%), follicular neoplasm (FN, n = 11, 20%), suspicious for malignancy (SM, n = 7, 13%), malignant (M, n = 8, 15%), and nondiagnostic (ND, n = 3, 5%). The FNA categories for non-incidental microcarcinoma were: B (n = 13, 22%), FLUS (n = 3, 5%), FN (n = 3, 5%), SM (n = 10, 17%), M (n = 29, 48%), and ND (n = 2, 3%).

CONCLUSIONS

Incidental microcarcinoma is not an uncommon entity, making up 21% (55 of 259) of malignant nodules on thyroidectomy. Indeterminate diagnoses (FLUS + FN + SM) accounted for the majority (60%) of preoperative FNAs for incidental microcarcinoma, compared with 27% for those of non-incidental microcarcinoma (P < 0.05, χ² test).

Autopsy Findings in Clinically Normal Thyroids

Thyroid glands obtained from 120 consecutive autopsies performed on patients who died from different causes, other than thyroid diseases, were systematically examined by light microscopy. There were 84 males and 36 females; their ages ranged from 1 day to 100 years. Histopathological findings were noted mainly in patients older than 48 years of age. In all cases thyroid lesions were incidental findings and included nodular goiter (26%), thyroiditis (9%), follicular adenomas (7%), papillary microcarci nomas (6%), follicular carcinoma (0.8%), and hemangioma (0.8%). A number of other morphologic changes of importance to surgical pathologists were also evaluated such as the presence of solid cell nests, intrathyroidal ectopic tissues, fibrosis, fat cell infiltration, and vascular changes. Int J Surg Pathol 1 (I): 25-32, 1993

Prognostic Impact of Ultrasonography Features and (18)F-Fluorodeoxyglucose Uptake in Patients With Papillary Thyroid Microcarcinoma

Objectives

To evaluate the prognostic impact of ultrasonography (US) features and ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) uptake in patients with papillary thyroid microcarcinoma (PTMC).

Methods

This study included 74 patients with a single PTMC diagnosed pathologically. Patients underwent total thyroidectomy, or near-total thyroidectomy and staging thyroid US and positron emission tomography (PET) were performed prior to surgery. US features of thyroid nodules were reviewed retrospectively and the maximum standard uptake value (SUV) of nodules was semiquantitatively analyzed on ¹⁸F-FDG PET/computed tomography (CT). Patients were followed-up for recurrence, which was defined as PTC on cytology results, elevated serum thyroglobulin (Tg) or anti-Tg antibody levels, or uptake on whole-body scintigraphy. We used univariate and multivariate analyses to evaluate whether poor prognostic outcomes were associated with US features or SUV values derived from PET/CT of nodules. In addition, subjects were divided into 2 groups for subgroup analyses: one with nodules equal to or larger than 5 mm and one with nodules smaller than 5 mm.

Results

Among the 74 patients, there was no recurrence. Thus we evaluated the correlation between SUV value and US features with poor prognostic factors of PTMC which included extrathyroid extension, central and lateral lymph node (LN) metastasis. However no clinicopathologic factors were associated with extrathyroid extension, central LN metastasis, or lateral LN metastasis.

Conclusion

In patients with PTMC, US features and SUV values on FDG-PET were not related to extrathyroid extension or LN metastasis. However, future studies with a larger sample size and longer follow-up should be performed to verify the results of this study.

Sonographic and Clinical Features of Papillary Thyroid Microcarcinoma Less than or Equal to Five Millimeters: A Retrospective Study

Objective

To retrospectively compare the sonographic and clinical features of papillary thyroid microcarcinoma (PTMC) ≤5 mm and PTMC >5 mm to improve the diagnostic value of ultrasonography.

Methods

A total of 367 cases of PTMC between January 2013 and December 2014 was included in this study. The patients were classified into group A (≤5 mm, n = 181) or group B (>5 mm, n = 186), and the sonographic and clinical features were reviewed and compared between the two groups.

Results

There was no significant difference in the shape, ratio of length/width, boundary, peripheral halo ring, echogenicity, cystic change and accompanying Hashimoto's thyroiditis between these two groups. However, the calcification (61.3% vs. 72.6%) and hypervascularity (13.8% vs. 24.7%) were more frequent in group B (p = 0.026 and 0.008, respectively). The patients were younger, and more patients were aged less than 45 years (41.4% vs. 57.0%) in group B. Capsular invasion (7.2% vs. 34.4%), multifocality (21.5% vs. 48.9%), bilaterality (17.1% vs. 39.8%), central lymph node metastasis (13.8% vs. 38.2%) and lateral lymph node metastasis (1.1% vs. 5.4%) were more frequent in group B. No clinical or sonographic feature was related to cervical lymph node metastasis in group A, while less than 45 years in age (p = 0.010), male gender (p = 0.040), capsular invasion (p<0.001), multifocality (p = 0.016) and calcification (p = 0.042) were related to cervical lymph node metastasis in group B.

Conclusions

The sonographic features of PTMC ≤5 mm were similar to those of PTMC >5 mm, including an irregular shape, a length/width ratio of ≥1, an unclear boundary, no peripheral halo ring, hypoechogenicity, no cystic change, calcification, no hypervascularity and no accompanying Hashimoto's thyroiditis. The clinical features of PTMC ≤5 mm were less aggressive than those of PTMC >5 mm.

BRAF(V⁶⁰⁰E) mutation and its association with clinicopathological features of papillary thyroid microcarcinoma: A meta-analysis

Recent studies have demonstrated that the BRAF(V600E) mutation is associated with aggressive clinicopathological features of papillary thyroid carcinoma (PTC). However, the BRAF mutation as a prognostic biomarker in papillary thyroid microcarcinoma (PTMC) is unclear. A systematic search of the electronic databases, including Medline, Scopus, CNKI and the Cochrane Library was performed up to July 1, 2014. Outcomes of interest included age, gender, concomitant hashimoto thyroiditis or nodular goiter, tumor size, pathological stage, tall cell variant of PTMC (TCVPTMC), multifocality, extrathyroidal extension (ETE) and lymph node metastasis (LNM). A total of 19 studies published from 2008 to 2014 comprising 2253 patients fulfilled the inclusion criteria and were included in the meta-analysis, and 1143 (50.7%) of these patients were BRAF mutation positive. BRAF mutation was associated with larger tumor size (OR: 1.64; 95% CI: 1.16-2.32), multifocality (OR: 1.58; 95% CI: 1.25-2.00), ETE (OR: 2.59; 95% CI: 2.03-3.29), LNM (OR: 1.73; 95% CI: 1.14-2.62), advanced stage (OR: 2.03; 95% CI: 1.14-3.64) and TCVPTMC (OR: 5.07; 95% CI: 1.49-17.27; P=0.009). Additionally, the BRAF mutation was found to be not associated with age, gender, concomitant hashimoto thyroiditis or nodular goiter (P>0.05 for all). This meta-analysis revealed that in patients with PTMC, BRAF mutation is associated with tumor size, multifocality, ETE, LNM, advanced stage and TCVPTMC, and it may be used as a predictive factor for prognosis of PTMC.

Lymph node metastasis in thyroid papillary microcarcinoma: a study of 170 patients

OBJECTIVE

Papillary microcarcinoma of the thyroid has been described as either a normal variant or a serious malignancy. We describe our experience with papillary microcarcinoma and lymph node metastases.

METHOD

A total of 685 consecutive total thyroidectomies with central compartment neck dissection were reviewed for papillary microcarcinoma. Association of central compartment lymph node metastases with age, gender, tumour multifocality, bilaterality and extrathyroidal extension was analysed.

RESULTS

Out of 170 papillary microcarcinoma cases, multifocality was found in 72 (42.4 per cent), bilaterality in 49 (28.8 per cent) and extrathyroidal extension in 16 (9.4 per cent). In all, 23 patients (13.5 per cent) had lymph node metastases. There was a significant association (p < 0.05) between extrathyroidal extension (but no other tumour characteristics) and lymph node metastases.

CONCLUSION

In all, 13.5 per cent of papillary microcarcinomas in our series showed lymph node metastases. Lymph node metastases were associated with extrathyroidal invasion of the papillary microcarcinoma.

Differences in the characteristics of papillary thyroid microcarcinoma ≤5 mm and >5 mm in diameter

BACKGROUND

The behavior and optimal management of papillary thyroid microcarcinomas (PTMCs) after thyroidectomy remain unclear. The purpose of this study was to compare the clinicopathologic features and tumor recurrence rates of patients with PTMCs ≤5 mm and >5 mm in diameter after total thyroidectomy.

METHODS

A group of patients with PTMCs ≤5 mm (n=83) has been compared to a group with >5 mm (n=122). All of these patients had conventional type PTMCs and were followed up for 5 years. Both the histology and the outcome have been compared.

RESULTS

Sex (p=.014) and extrathyroidal extension (p=.003) of patients in the ≤5 mm and >5 mm groups differed significantly. Two and 5 patients from these groups, respectively, experienced tumor recurrence within 5 years (2.4% vs 4.1%; p=.634).

CONCLUSION

The clinicopathologic features of PTMCs ≤5 mm and >5 mm are similar, except for sex distribution and extrathyroidal extension. The 5-year recurrence rate in the 2 groups did not differ significantly.

Tumor classification in well-differentiated thyroid carcinoma and sentinel lymph node biopsy outcomes: a direct correlation

BACKGROUND

Predicting locoregional metastasis in well-differentiated thyroid carcinoma (WDTC) is a challenge for thyroid cancer surgeons. Sentinel lymph node biopsy (SLNB) has been shown to be an effective predictive tool. To our knowledge, primary tumor (T) classification has yet to be studied with regard to SLNB. We hypothesized that larger primary tumors would correlate with the rate of malignancy in SLNBs.

METHODS

A retrospective chart review was conducted on patients operated for WDTC at the McGill Thyroid Cancer Center over a 36-month period. Patients who underwent a total thyroidectomy and SLNB for WDTC were included in this study.

RESULTS

A total of 311 patients were included and separated into two groups (236 negative and 75 positive SLNBs). Among patients with negative SLNBs, 65% had T1 primary tumors, 17% T2, 16% T3, and 2% T4, whereas 18% of patients with positive SLNBs had T1 primary tumors, 5% T2, 45% T3, and 32% T4 (p<0.001). Patients under the age of 45 years had a higher rate of positive SLNs (36% in those <45 years vs. 17% in those ≥ 45 years; p<0.001).

CONCLUSIONS

Age (<45 years) and higher T category were found to be associated with a higher rate of positive SLNBs.

Clinical characteristics of papillary thyroid microcarcinoma less than or equal to 5 mm on ultrasonography

Management of papillary thyroid microcarcinoma sized ≤5 mm identified on ultrasonography is controversial. In this study, we evaluated the clinical characteristics of papillary thyroid microcarcinoma sized ≤5 mm on ultrasonography in comparison to those >5 mm and sought to present rationales for optimal management in papillary thyroid microcarcinoma ≤5 mm. The medical records of 396 patients who underwent surgery for papillary thyroid carcinoma between 2009 and 2011 were retrospectively analyzed. The patients were grouped into A (≤5 mm, n = 132) or B (>5 mm, n = 264) and the clinicopathologic characteristics of the patients were reviewed and compared between the two groups. Tumor capsular invasion (45.5 vs. 59.8 %, p = 0.007) and cervical lymph node metastasis (18.2 vs. 29.2 %, p = 0.018) were more frequent in group B. Nonetheless, group A presented lymph node metastasis in 42.3 % of multifocal cases showing no difference to that of group B (41.5 %, p = 0.946) and also included five cases (3.8 %) of lateral neck metastasis. Multifocality was the only predictive factor for lymph node metastasis in group A (p < 0.001). Over half (55.3 %) of the patients of group A were diagnosed with papillary carcinoma in private clinics; however, only 5.5 % of these patients underwent assessment of lateral neck lymph nodes initially. In conclusion, higher risk of cervical lymph node metastasis should be considered in evaluation and surgical decision of papillary thyroid microcarcinoma ≤5 mm identified on ultrasonography with multifocality. Evaluation of the cervical lymph nodes including the lateral neck should not be overlooked when suspicious thyroid nodule suggesting malignancy sized ≤5 mm shows multifocal lesions.

Immunohistochemical analysis based Ep-ICD subcellular localization index (ESLI) is a novel marker for metastatic papillary thyroid microcarcinoma

Background

Thyroid cancer is among the fastest growing malignancies; almost fifty-percent of these rapidly increasing incidence tumors are less than or equal to 1cm in size, termed papillary thyroid microcarcinoma (PTMC). The management of PTMC remains a controversy due to differing natural history of these patients. Epithelial cell adhesion molecule (EpCAM) is comprised of an extracellular domain (EpEx), a single transmembrane domain and an intracellular domain (Ep-ICD). Our group reported nuclear Ep-ICD correlated with poor prognosis in thyroid cancer (Ralhan et al., BMC Cancer 2010,10:331). Here in, we hypothesized nuclear and cytoplasmic accumulation of Ep-ICD and loss of membranous EpEx may aid in distinguishing metastatic from non-metastatic PTMC, which is an important current clinical challenge. To test our hypothesis, Ep-ICD and EpEx expression levels were analyzed in PTMC and the staining was correlated with metastatic potential of these carcinomas.

Methods

Thirty-six PTMC patients (tumor size 0.5 - 1cm; metastatic 8 cases and non-metastatic 28 cases) who underwent total thyroidectomy were selected. The metastatic group consisted of patients who developed lymph node or distant metastasis at diagnosis or during follow up. The patients’ tissues were stained for Ep-ICD and EpEx using domain specific antibodies by immunohistochemistry and evaluated.

Results

PTMC patients with metastasis had higher scores for nuclear and cytoplasmic Ep-ICD immunostaining than the patients without metastasis (1.96 ± 0.86 vs. 1.22 ± 0.45; p = 0.007 and 5.37 ± 0.33 vs. 4.72 ± 1.07; p = 0.016, respectively). Concomitantly, the former had lower scores for membrane EpEx than the non-metastatic group (4.64 ± 1.08 vs. 5.64 ± 1.51; p = 0.026). An index of aggressiveness, Ep-ICD subcellular localization index (ESLI), was defined as sum of the IHC scores for accumulation of nuclear and cytoplasmic Ep-ICD and loss of membranous EpEx; ESLI = [Ep − ICD_nuc + Ep − ICD_cyt + loss of membranous EpEx]. Notably, ESLI correlated significantly with lymph node metastasis in PTMC (p = 0.008).

Conclusion

Nuclear and cytoplasmic Ep-ICD expression and loss of membranous EpEx were found to correlate positively with metastasis in PTMC patients. In addition, ESLI had the potential to identify metastatic behavior in PTMC which could serve as a valuable tool for solving a current dilemma in clinical practice.

Factors influencing the outcome of patients with incidental papillary thyroid microcarcinoma

Objective. To analyze some factors that could influence the outcome of patients with PTMC. Material and Methods. This is a longitudinal observational study. All patients diagnosed and treated for papillary thyroid microcarcinoma at the University Hospital of Vigo, between January 1994 and December 2003, were included in the present study. Demographic characteristics, tumour characteristics, TNM stage, rate of recurrence, and treatment with ¹³¹I were the study variables. Results. Ninety-one patients (75 females) with an average age of 47.7 ± 13.4 years, range 19–81, were studied. Initial tumour staging was T1 in 90 patients and T4a in 1 case. Initial lymph node involvement was present in 4 cases (4.4%). We only found one case with distant metastases at diagnosis. Postsurgical evaluation of thyroid specimens revealed that 28 (30.7%) tumours were multifocal. The average size of the tumour was 0.44 ± 0.25 cm, range 0.1–1. Univariate analysis reveals a statistically significant association between tumour multifocality and postsurgical ¹³¹I therapy with the recurrence rate. In the multivariate analysis only multifocality (P = 0.037, HR 5.7) was a significant risk factor for the recurrence rate. Conclusions. Our results indicate that tumour multifocality is an independent predictor of relapse but neither the tumour size nor postsurgical ¹³¹I therapy.

Impact of clinicopathologic factors on subclinical central lymph node metastasis in papillary thyroid microcarcinoma

PURPOSE

We evaluated whether the clinicopathological factors of papillary thyroid microcarcinoma (PTMC), especially tumoe size, are associated with subcinical central lymph node metastasis.

MATERIALS AND METHODS

A total of 160 patients diagnosed with PTMC who underwent total thyroidectomy with bilateral central lymph node dissection were enrolled in this study. All patients were clinically lymph node negative PTMC. Patients were divided into 2 groups according to the size of tumor (≤5 mm vs. >5 mm). Clinicopathologic risk factors for subclinical central lymph node metastasis were analyzed.

RESULTS

Subclinical central lymph node metastasis was detected in 61 (38.1%). Patients with tumors ≤5 mm had a lower frequency of extrathyroidal extension, multifocality and subclinical central lymph node metastasis. On multivariate analysis, only male and tumor size >5 mm were independent predictors of subclinical central lymph node metastasis; age, multifocality, bilaterality, extrathyroidal extension, lymphvascular invasion and lymphocytic thyroiditis were not.

CONCLUSION

In this study, male and tumor size >5 mm were two independent predictive factors for subclinical central lymph node metastasis in PTMC. These are easier factors to assess before surgery than other factors when planning the central lymph node dissection. However, further long-term follow-up studies are needed to confirm the prognostic significance of subclinical central lymph node metastasis in PTMC.

Current treatment of papillary thyroid microcarcinoma

PTMC is being diagnosed with increasing frequency and generally has an excellent prognosis with less than 0.5% disease-specific mortality. Better prognostic stratification, especially for high-risk patients, helps to optimize surgical care. Older age, extrathyroidal invasion, lymph node involvement, and distant metastases are usually regarded as the most potent risk factors for patients with PTMC. Total or near-total thyroidectomy is advocated as the initial therapy for most primary PTMCs, whereas neck dissection is only recommended with the presence of cervical lymphadenopathy or T4 tumors. ATA suggests that postoperative RAI ablations be administrated to patients with gross extrathyroidal invasion or distant metastases. RAI ablation may also facilitate the use of serum Tg concentrations for postoperative risk assessment.

Thyroid microcarcinoma

Nowadays the most commonly occurring differentiated thyroid cancer in many countries is a microcarcinoma in patients older than 45 years, incidentally found during neck ultrasound. In view of their low morbidity and mortality, the crucial point is how to manage such microcarcinomas. Recently published European and American guidelines aim to minimize the diagnostic and therapeutic procedures without affecting the diagnostic accuracy and the therapeutic effectiveness, keeping in mind that we are dealing with patients who have a normal life expectancy and to whom we have to guarantee an excellent quality of life. The present review will summarize the clinical and pathological features of thyroid microcarcinoma, including its definition, prevalence, presentation, pathology, genetic, clinical impact and will try to derive from them a rationale for therapeutic and diagnostic intervention.

Ipsilateral and contralateral central lymph node metastasis in papillary thyroid cancer: patterns and predictive factors of nodal metastasis

BACKGROUND

The aims of this study were to evaluate the rate and risk factors of ipsilateral and contralateral central lymph node (CLN) metastases in patients with papillary thyroid cancer (PTC).

METHODS

A total of 161 patients who underwent total thyroidectomy with prophylactic CLN dissection (CLND) to treat PTC were enrolled.

RESULTS

Of 134 total cases excluding tumors located in the isthmus and bilateral lobes, 72 cases (53.7%) involved CLN metastases. Tumor size, age, and sex were found to be predictive of ipsilateral CLN metastasis and the rate of ipsilateral CLN metastasis in tumors > 1 cm was 59.6%. Contralateral CLN metastases were more prevalent only in tumors that already had ipsilateral CLN metastases (27.3%, p = .002).

CONCLUSIONS

It is suggested that risk factors of ipsilateral and contralateral CLN metastases should be considered while planning the extent of CLND in patients with clinically node-negative and unilateral PTC upon preoperative ultrasonography.

Thyroid microcarcinoma

Nowadays the most commonly occurring differentiated thyroid cancer in many countries is a microcarcinoma in patients older than 45 years, incidentally found during neck ultrasound. In view of their low morbidity and mortality, the crucial point is how to manage such microcarcinomas. Recently published European and American guidelines aim to minimize the diagnostic and therapeutic procedures without affecting the diagnostic accuracy and the therapeutic effectiveness, keeping in mind that we are dealing with patients who have a normal life expectancy and to whom we have to guarantee an excellent quality of life. The present review will summarize the clinical and pathological features of thyroid microcarcinoma, including its definition, prevalence, presentation, pathology, genetic, clinical impact and will try to derive from them a rationale for therapeutic and diagnostic intervention.

Prognostic factors affecting neck lymph node recurrence and distant metastasis in papillary microcarcinoma of the thyroid: results of a study in 445 patients

BACKGROUND

The management of thyroid papillary microcarcinoma (PMC) is controversial. Total thyroidectomy, thyroid lobectomy/isthmectomy, and even no treatment have been proposed. We investigated the clinical course and prognostic factors for disease recurrence and distant metastasis in 445 patients with PMC.

METHODS

Data from 445 patients diagnosed with PMC in the period from 1978 to 2003 were reviewed and analyzed. Total thyroidectomy was performed in 404 patients and loboisthmusectomy in 41. Neck dissection took place in 226 patients (49.7%), with 166 of only the central compartment and 60 of both the central and lateral compartments. Radioiodine ((131)I) ablation treatment was given to 389 patients.

RESULTS

Median tumor size was 7 mm (range 1-10 mm). PMC was multifocal in 156 cases (35%) and bilateral in 60 cases (13.5%). Extrathyroidal tumor extension (pT3) and neck lymph node metastasis (pN1) were present in 133 (30%) and 182 (40.9%) patients, respectively. Capsular invasion without extrathyroidal tumor extension was observed in 39 (8.7%) patients. Mean follow-up was 5.3 (range 1-26) years. Seventeen (3.8%) patients had recurrence or persistence of disease: neck recurrence (NR) in 12 (2.7%), distant metastasis (DM) in four (0.9%), NR + DM in one (0.2%). One patient (0.2%) died of the disease. Capsular invasion, extrathyroidal tumor extension (pT3), and neck lymph node metastasis at presentation (pN1) were the only independent risk factors for NR and/or DM occurrence (p < 0.05). Patients not showing these features, who were treated with loboisthmusectomy only, never experienced disease recurrence.

CONCLUSION

Total thyroidectomy seems advisable in PMC with extrathyroidal extension and neck lymph node metastasis at presentation. Capsular invasion without extrathyroidal extension may suggest aggressive tumor behavior and require radical treatment.

Well-differentiated thyroid carcinoma: comparison of microscopic and macroscopic disease

BACKGROUND

The rapid increase in the incidence of well-differentiated thyroid cancer in recent years is the result of smaller thyroid tumors (1 cm or less) being diagnosed more frequently. Few studies are available regarding the appropriate approach to this previously known postmortem incidental finding, and their results remain controversial.

METHODS

In 2005, our center started a registry of all patients with nonmedullary thyroid carcinoma who were followed at our institute. In the present study, data on the background, clinical, and outcome characteristics were collected from the registry for 225 patients with microscopic disease and 543 patients with macroscopic disease.

RESULTS

Patients with microscopic disease were slightly older (51 vs. 47.5 years, p = 0.003), had a higher female to male ratio (189:37 vs. 419:123; p = 0.06), and were affected more by papillary carcinoma (98.2% vs. 85.5%; p < 0.001). Multifocal disease was documented in 50.2% of the patients with microscopic disease and 46.8% of the patients with macroscopic disease (NS), and bilateral disease, in 42.6% and 36.8%, respectively (NS). Corresponding rates for the two groups for other tumor-related factors were as follows: lymph node involvement at initial treatment, 25.7% and 30% (NS); distant metastases, 2.4% and 5.1% (p = 0.16); persistent/recurrent disease, 11% and 32% (p < 0.001); and new distant metastases, 2.65% and 6.5% (p = 0.07). At a median follow-up of 5 years, 96% of the microscopic carcinoma group were disease free compared to 77% of the macroscopic group (p < 0.001).

CONCLUSION

The differences between patients with microscopic and macroscopic well-differentiated thyroid carcinoma may not justify a different therapeutic approach.

Prevalence of thyroid cancer at a medical screening center: pathological features of screen-detected thyroid carcinomas

PURPOSE

To assess the incidence of thyroid malignancy in an adult population screened by high-resolution ultrasonography at a medical screening center and to compare the clinical and pathological features of screen-detected thyroid carcinomas to symptomatic overt thyroid carcinomas.

MATERIALS AND METHODS

We calculated the prevalence of screen-detected thyroid cancer at a medical screening center using high- resolution ultrasonography and fine needle aspiration. We then compared the clinical and pathological features of screen-detected thyroid cancers (n = 46) to clinical symptomatic thyroid cancers (n = 157). We evaluated age, gender, size, perithyroidal extension, lymphovascular extension, stage, histological lymph node metastasis, and the type of cancer. We also compared the above findings of micropapillary carcinomas to papillary thyroid carcinomas that were larger than 1cm in diameter.

RESULTS

Screen-detected thyroid nodule patients were 2,747 (37%) of 7,491 patients. Nodules selected for fine needle aspiration were 658 and cytology confirmed malignancy were 79 (12%) nodules. When screen-detected thyroid cancers (n = 46) were compared to symptomatic overt thyroid cancers (n = 157), only statistically significant factor was size (p = 0.002). Papillary thyroid carcinomas that were larger than 1 cm had more frequent capsular invasion (p = 0.000) and a higher stage (p = 0.027), and a higher prevalence of lymph node metastases (p = 0.002).

CONCLUSION

Screen-detected thyroid cancers should be managed as same as symptomatic thyroid cancers in respect to size, and an assessment should strictly be based on the ultrasound features and fine needle aspiration biopsy findings.

Predictive factors for central compartment lymph node metastasis in thyroid papillary microcarcinoma

OBJECTIVE

We examined the incidence of nodal involvement and attempted to determine the predictive factors for central compartment lymph node (LN) metastasis in thyroid papillary microcarcinoma (PMC).

STUDY DESIGN

Retrospective chart review.

METHODS

We undertook a retrospective study of 52 patients treated between January 2000 and December 2005 for PMC by total thyroidectomy and elective central compartment LN dissection with or without comprehensive lateral neck dissection (n = 9). There were 45 women and 7 men whose mean age was 47.6 +/- 11.5 years. The following criteria were used to study the predictive value of central compartment LN metastasis: sex, age, multifocality of the tumor, extracapsular spread (ECS), the involvement of the lateral neck LN, tumor size, and tumor location.

RESULTS

In 16 of 52 (31%) patients, central compartment LN metastasis was found. With use of univariate and multivariate analysis, ECS, lateral LN metastasis, and tumor size (>5 mm) were independent correlates of central compartment metastasis. Sex, age, multifocality, and tumor location were not associated with central compartment LN metastasis and did not significantly influence the predictive value of these variables.

CONCLUSIONS

We found a significant association among ECS, lateral LN metastasis, tumor size (>5 mm), and central compartment LN metastasis in patients with PMC. A prophylactic neck dissection of the central compartment should be considered particularly in patients with ECS of the tumors, metastatic LN in the lateral neck, and a greater than 5 mm tumor size.

Clinical features and therapeutic implication of papillary thyroid microcarcinoma

Papillary thyroid microcarcinomas (PTMs) are small tumors (< or =1 cm of diameter) that belong to the well-differentiated low-risk carcinomas of the thyroid, which are characterized by benign behavior, probably of little clinical significance, and do not affect patients' survival. They are found in otherwise normal thyroids or in multinodular goiters with a clinical frequency varying substantially according to different series. Sometimes, PTM may be associated with lymph node metastases at presentation and/or locoregional recurrences during follow-up. Distant metastases are extremely rare, but have been reported. Although deaths related to PTM are almost unknown, PTM raises therapeutic implications. This review addresses the issue of definition, treatment, and follow-up of PTM.

Clinical, histopathological, and molecular characteristics of papillary thyroid microcarcinoma

BACKGROUND

Papillary thyroid microcarcinoma (PTMC) detection has been increasing explosively with the recent improvement and application of new diagnostic tools. However, the associations between clinical, histopathological, and molecular findings are often not fully evaluated in reaching a decision for the treatment of PTMC.

OBJECTIVE

To retrospectively evaluate the patients diagnosed with PTMC in terms of the clinical and histopathological features and the immunohistochemical findings of specific molecular markers, and thereby provide an association with the disease prognosis for the Korean patients.

DESIGN

We have reviewed the clinical records of patients who underwent surgery for thyroid cancer (during January 2000 to August 2006 interval) at St. Mary's Hospital, Seoul, Korea. The clinical and histopathological characteristics of 217 PTMCs were evaluated cross-sectionally after surgery, and immunohistochemical staining of p53, epidermal growth factor receptor (EGFR), Ki-67, and cyclooxygenase-2 (COX-2) for 87 isolated specimens was performed.

MAIN OUTCOME

The proportions of extrathyroid extension, lymphatic invasion, and lymph node metastasis cited were 31.9%, 19.2%, and 17.8%, respectively. However, distant metastasis was not noted. Fifty-three (27.1%) patients had multiplicity, and 39 patients (20.0%) had bilateral disease. A primary tumor larger than 5 mm was significantly associated with extrathyroid extension, lymphatic invasion, and lymph node metastasis. The absence of EGFR expression shown by immunohistochemical analysis was closely correlated with extrathyroid extension and lymph node metastasis, while the absence of COX-2 expression was associated with multiplicity and bilaterality.

CONCLUSION

Many patients with PTMC had clinical and histopathological poor prognostic factors. The expression of molecular markers, such as EGFR and COX-2, may have a role in the prognosis of PTMC. When considering all of the prognostic factors, a more tailored management approach appears to be necessary for patients with PTMC.

Incidental papillary microcarcinoma of the thyroid--factors affecting lymph node metastasis

BACKGROUND AND AIMS

Despite the overall excellent prognosis for patients with thyroid papillary microcarcinoma (PMC), these tumors are associated with lymph node metastasis. The aim of this study is to identify the rate of lymph node metastasis and evaluate the clinical and pathological factors affecting metastasis in thyroid PMC.

METHODS

Among 475 patients with papillary thyroid carcinoma treated between 1990 and 2003, 81 patients (17%) were diagnosed as PMC and the records of these patients were evaluated retrospectively. Clinicopathologic features were evaluated by univariate and multivariate analyses.

RESULTS

According to age, metastases, extent, and size risk definition, all patients were in low-risk group. Lymph node metastases were determined in 12.3% of patients. Mean follow-up was 7 years (range from 28 to 192 months). Ten-year disease-free and overall survival rates were 97 and 100%, respectively. Both multifocality and thyroid capsular invasion were found to be independent risk factors for lymph node metastasis by multivariate analysis.

CONCLUSION

Patients with thyroid PMC in low-risk group with multifocal tumors and with capsule invasion may have increased risk of lymph node metastasis, and must be considered in follow-up of the patients who have these factors.

Microcarcinoma da tireóide: experiência e conduta em clínica privada

OBJETIVO: Estudar o microcarcinoma papilífero observado nas tireoidectomias realizadas em nossa clínica privada. MATERIAL E MÉTODOS: Revisamos clínica e histologicamente 1.930 pacientes submetidos a tireoidectomias no período de 2002 a 2006, tendo 606 carcinomas e, desses, 332 como microcarcinomas papilíferos. Avaliamos sexo, idade, tipo histológico, tamanho da neoplasia, multifocalidade, freqüência do esvaziamento cervical, resultados da PCI e tireoglobulina sérica. RESULTADOS: Dos 332 pacientes, 48 eram do sexo masculino e 146 tinham idade superior a 45 anos. Todos foram submetidos a tireoidectomia total, 19 concomitantemente a esvaziamento cervical de necessidade (5,72%), e 313 a iodoterapia (94,27%). Tivemos metástase a distância em 5 pacientes (1,5%). Após 1 ano, de 170 pacientes submetidos à PCI, temos 141 considerados livres de doença, 21 com anti-tireoglobulina positivo, 6 com tireoglobulina superior a 2 ng/ml, sendo 1 com metástase pulmonar e outro com recidiva linfonodal (0,3%). CONCLUSÃO: Recomendamos que seja realizada a tireoidectomia total, esvaziamento cervical de necessidade e iodoterapia ablativa na presença de fatores clínicos e anátomo-patológicos de risco.

Unusual findings in papillary thyroid microcarcinoma suggesting partial regression: a study of two cases

Histologic changes of regression have been recognized in many malignant tumors, although they have not been documented in thyroid carcinoma. We analyze here the histologic features of 2 cases of papillary thyroid microcarcinoma, one of the diffuse sclerosing variant and another multicentric of the follicular variant, that suggest partial regression. The histologic and clinical features of the 2 thyroid microcarcinomas were compared with the features of regression reported in other tumors. Hematoxylin and eosin stains were examined in each case. In addition, immunoperoxidase stains for thyroglobulin and thyroid transcription factor-1 were performed on the metastatic and primary lesions of each case. Immunostains for CD4 and CD8 performed on the thyroid lesions were also examined. Both patients presented with metastatic papillary thyroid carcinoma in regional lymph nodes with no clinical or radiologic evidence of primary tumor in the thyroid glands. When examined, the thyroid glands revealed only microscopic foci of papillary thyroid carcinoma measuring less than 1.5 mm, diffuse sclerosis and a lymphocytic infiltrate mainly composed of cytotoxic T lymphocytes around the neoplastic microfollicles. Numerous psammoma bodies were also found in the thyroid of case 1, and venulitis similar to that seen in acute hepatic rejection was also seen in the microcarcinoma of case 2. The 2 patients reported had papillary thyroid microcarcinomas measuring less than 1.5 mm and features suggestive of regression characterized by extensive fibrosis, an accompanying T lymphocyte infiltrate, venulitis, and only a few clusters of neoplastic cells or a few neoplastic follicles. Thus, we believe that these histologic changes suggest regression because papillary thyroid microcarcinomas measuring less than 1.5 mm do not metastasize and have been considered innocuous or medical curiosities.

Disparities between male and female patients with thyroid cancers: sex difference or gender divide?

OBJECTIVE

This investigation was undertaken to quantify histopathological disparities between male and female patients with sporadic and hereditary thyroid cancers, which may reflect a biological 'sex difference' or a behavioural 'gender divide'.

DESIGN

Retrospective cohort analysis (November 1994-January 2006).

PATIENTS

1298 Consecutive surgical patients with sporadic papillary (n = 587), sporadic follicular (n = 232), sporadic medullary (n = 320), and hereditary medullary thyroid cancers (n = 159) from a tertiary referral centre.

MEASUREMENTS

Age at diagnosis of cancer, primary tumour diameter, frequency of extrathyroidal extension, lymph node and distant metastases, and cancer subtypes.

RESULTS

Primary diameters of sporadic tumour entities (papillary, 26.0 vs. 19.3 mm; follicular, 54.9 vs. 35.1 mm; and medullary, 27.9 vs. 20.8 mm), but not hereditary medullary cancers, were significantly (P <or= 0.001) larger in male patients. Likewise, lymph node metastases from sporadic papillary cancers (60%vs. 44%, P < 0.001), the insular subtype in sporadic follicular cancers (22%vs. 8%, P = 0.003), extrathyroidal extension of sporadic medullary cancers (35%vs. 15%, P < 0.001), and distant metastases from sporadic medullary cancers at the most recent operation (29%vs. 15%, P = 0.002) were seen significantly more often with male patients. No significant differences were observed between male and female patients with hereditary medullary cancers, half of which were detected by screening.

CONCLUSIONS

Our data emphasize the need for earlier diagnosis and intervention in male patients to ensure that male sex will cease sometime to constitute an ominous prognostic marker of advanced thyroid cancer.

Frequent, aggressive behaviors of thyroid microcarcinomas in korean patients

The incidence of thyroid microcarcinoma is rising due to the frequent use and improvement of fine-needle aspiration biopsy and ultrasonography. Since the recent update of the TNM (Tumor, Node, Metastasis) staging system for thyroid cancer, the importance of lymph node metastasis became more prominent. In the present study, we evaluated the prognostic factors and extension of thyroid microcarcinomas in Korean patients. The clinical and pathological findings in patients with thyroid microcarcinomas in a Korean hospital from January through December 2004 were evaluated. A total of 302 (50.2%) out of 601 cases of thyroid cancers were microcarcinomas. Evaluation of the histology revealed that nearly all of the cases (300 of 302) were of the papillary type. Analyzing patients of papillary thyroid microcarcinomas, 273 (91.0%) out of 300 patients of papillary microcarcinomas were women. Seventy-eight (26.0%) cases contained multiple tumor masses (> or =2), including 49 (16.3%) cases that were bilateral. There were 84 (28.0%) cases of extrathyroidal extensions and 89 cases (29.7%) of lymph node metastasis, but no cases of distant metastases. Application of the new staging system revealed 7 (2.3%) cases that changed from stage III to stage IVA. Thyroid microcarcinomas were also associated with poor prognostic factors and appear to exist at relatively higher cancer stages. Therefore, it is important to treat them as early and as vigorously as possible with extensive surgery, radioactive iodine therapy, and thyroxine suppression.

Papillary microcarcinomas of the thyroid gland and immunohistochemical analysis of expression of p53 protein in papillary microcarcinomas

Background

Thyroid papillary microcarcinoma (TPM) is defined according to WHO criteria as a thyroid tumor smaller than 1–1.5 cm. TPMs are encountered in 0.5–35.6 % of autopsies or surgical specimens where carcinoma had been unsuspected. The purpose of the present study was to evaluate patients who had TPMs in terms of clinical findings, histopathological features and immunohistochemical evidence of expression of the tumor suppressor gene p53.

Methods

A total of 44 patients with TPMs less than 1.0 cm in diameter were included in the study. The patients were evaluated clinically and the tumors were evaluated in terms of their histopathological and immunohistochemical features, including expression of p53.

Results

The female/male ratio was 2.8/1, and the median age at time of diagnosis was 49 years (range 20–71 years). The maximum diameter of the smallest focus was 0.1 mm, and that of the largest was 10 mm microscopically. The mean diameter of all tumors was 5.7 mm. There was no correlation between tumor size and age or gender. Of the TPMs, 72 % were found in the right lobe, 24 % in the left lobe and 4 % in the isthmus. Fine-needle aspiration biopsy provided the diagnosis of TPM in only 43.2 % of the patients. All patients were treated with surgery, with 20 undergoing conservative surgery, i.e. lobectomy or isthmusectomy, and 24 undergoing total thyroidectomy. Frozen section provided the diagnosis of TPM in only 56.8 % of the patients. We found lymphocytic thyroiditis in 13.6% of patients, follicular variants in 11.9%, capsular invasion in 26.8%, lymph node involvement in 11.9%, soft tissue metastases in the neck in 12.1% and multifocality in 31.7 %, and none of these were related to age or gender (p > 0.05). No distant metastases were observed during approximately 10 years of follow up. We found p53 positivity in 34.5 % of TPM tumors. However, p53 expression was not statistically related to age or gender.

Conclusion

Our findings imply that TPMs may not be entirely innocent since they are associated with signs of poor prognosis such as capsular invasion, multifocal presentation, lymph node involvement and p53 positivity. Therefore, TPMs should be evaluated and followed like classical papillary cancers.

Papillary thyroid microcarcinoma: A surgical perspective

Papillary thyroid microcarcinoma (PTMC) is defined as a papillary thyroid cancer measuring less than 10mm in its greatest diameter. It is the most common form of thyroid cancer, detected in up to 36% in autopsy studies. The wide availability and use of neck ultrasonography in the evaluation of carotid arteries and of the thyroid resulted in an increased detection of PTMC. PTMC is often multifocal. The diagnosis is usually based on a combination of clinical examination, laboratory investigations, and specialized radiological techniques (mainly neck ultrasonography combined with fine-needle aspiration cytology). A common scenario is the diagnosis of PTMC as an incidental finding following thyroidectomy for a presumably benign thyroid disease. Despite some controversy, most authors agree that PTMC should be treated by total or near-total thyroidectomy, provided it can be performed safely. Because of its many and major advantages, in our clinical practice, total or near-total thyroidectomy is the procedure of choice for the management of PTMC. Given the high incidence of PTMC as an incidental finding and the frequent multi-focality, we also favor total or near-total thyroidectomy for the surgical management of nodular thyroid disease (multinodular goiter or dominant presumably benign thyroid nodule/s). Despite some controversy, we perform central neck lymph node dissection electively, in the presence of cervical lymphadenopathy. Radioiodine ablation therapy may be used as an adjuvant therapy. Prognostic factors (such as tumor multicentricity, positive lymph nodes, capsular or vascular invasion) or scoring systems (such as the AMES) can be used to select patients for radioiodine adjuvant therapy. Suppression therapy is needed after surgical management. Despite the potential for neck lymph node and even distant metastases, the biological behavior of PTMC is in general benign and the prognosis is very good.

Natural history, diagnosis, treatment and outcome of papillary thyroid microcarcinoma (PTMC): a mono-institutional 12-year experience

The clinical and histopathological records of 149 consecutive patients with papillary thyroid microcarcinoma (PTMC), homogeneously studied and operated on by the same surgeon in the period 1990 to 2001, were reviewed. After a mean 6.5-year follow-up, three cases of loco-regional recurrence (2%) were observed. These three patients had all undergone partial thyroidectomy only and tumour relapse occurred in the residual thyroid tissue. No recurrence was observed in patients treated by total thyroidectomy and I. At variance with other reported series, no lymph node recurrence was observed in our series, in particular in the group of 23 patients with evidence of nodal metastases at initial diagnosis (three of whom were revealed by I scan after surgery). Therefore, a preventive effect of I treatment in our patient population can be hypothesized. However, prolonged follow-up will be necessary to clarify this. Due to the inability of current imaging modalities to select pre-operatively PTMC patients at risk for recurrence (presence of thyroid capsular invasion, multifocality and microscopic lymph node metastases), it appears reasonable to offer the patient total thyroidectomy when a pre-operative diagnosis of PTMC is reached. Moreover, the policy of our thyroid cancer centre is that, in these patients, post-surgical I scan should be obtained in order to detect unknown metastatic deposits, and I treatment should also be considered in patients with poor clinical and histopathological prognostic factors. In contrast, in patients operated on for benign thyroid disease and with delayed diagnosis of PTMC at definitive histopathological examination, re-operation might be avoided in the presence of unifocal disease without thyroid capsular invasion and with ultrasound-'normal' residual thyroid tissue. Close clinical and ultrasound follow-up is recommended, especially in patients who have undergone conservative surgery only.

Papillary microcarcinoma of the thyroid-Prognostic significance of lymph node metastasis and multifocality

BACKGROUND

It is known that patients with papillary microcarcinoma (PMC) of the thyroid gland have a very favorable prognosis. The rising incidence of PMC among papillary thyroid carcinoma (PTC) necessitates the identification of prognostic factors and the formulation of treatment protocols.

METHODS

The authors conducted a retrospective analysis of 203 patients with PMC who were diagnosed on or before 1999 and were treated at the Department of Clinical Oncology, Queen Elizabeth Hospital, Hong Kong.

RESULTS

The cause specific survival, locoregional (LR) failure free survival, and distant metastases failure free survival rates at 10 years were 100%, 92.1%, and 97.1%, respectively. Five patients had lung metastases; 2 patients died of their metastases 12.9 years and 14.8 years after diagnosis, and 3 patients achieved clinical remission after radioiodine (RAI) treatment. Twelve patients had LR recurrences. Patients with LR recurrence were highly salvageable with a combination of surgery, RAI treatment, and external radiotherapy; all but one (who refused treatment) were alive without disease at last follow-up. Multivariate analyses did not reveal any independent prognostic factor for survival. The risk of cervical lymph node (LN) recurrence increased 6.2-fold (P = 0.01) and 5.6-fold (P = 0.02) when LN metastases and multifocal disease were present at diagnosis. RAI ablation reduced the LN recurrence rate to 0.27 (P = 0.04). The presence of LN metastasis increased the rate of distant metastasis 11.2-fold (P = 0.03). Age was not a significant factor in predicting disease recurrence or survival. Subdivision by tumor sizes </= 5 mm and > 5 mm did not affect the outcome, but no patient with tumors <or= 5 mm had mortality related to PMC.

CONCLUSIONS

Despite the overall excellent prognosis for patients with PMC, PMC was associated with a 1.0% disease-related mortality rate, a 5.0% LN recurrence rate, and a 2.5% distant metastasis rate. Therefore, the treatment of patients with PMC should be no different from the treatment of patients with conventional PTC: i.e., complete surgery with consideration for RAI and/or external radiation therapy if poor prognostic factors are present.

Lymph node metastasis from 259 papillary thyroid microcarcinomas: frequency, pattern of occurrence and recurrence, and optimal strategy for neck dissection

OBJECTIVE

To determine the frequency and pattern of lymph node metastasis (LNM) from papillary thyroid microcarcinoma (PTMC) and the results of node dissection, and to establish the optimal strategy for neck dissection in these patients.

SUMMARY BACKGROUND DATA

Most PTMCs carry a favorable prognosis, but a few present with palpable lymphadenopathy. Patients with LNM are at risk for nodal recurrence, although they do not have higher mortality. The frequency and pattern of LNM from PTMC and the results of node dissection are not well established.

METHODS

The frequency and pattern of LNM from 259 PTMCs were analyzed according to the size and location of the primary tumor. Of the 259, 24 with palpable nodes underwent therapeutic node dissection and the other 235 patients without palpable nodes underwent prophylactic node dissection. The authors compared the results of node dissection between the therapeutic group and the prophylactic group, and between PTMCs 5 mm or smaller and PTMCs larger than 5 mm. The authors also compared nodal recurrence between the prophylactic group and a no-lymph-node-dissection group (155 PTMCs).

RESULTS

Overall, 64.1% (166/259) and 44.5% (93/209) had node involvement of the central and ipsilateral lateral compartment, respectively. Pretracheal (43.2%), ipsilateral central (36.3%), and ipsilateral mid-lower (37.8%) jugular were more commonly involved. LNM was more frequent in the therapeutic group than in the prophylactic group (95.8% vs. 60.9% for central compartment, 83.3% vs. 39.5% for ipsilateral lateral compartment). Nodal recurrence was more common in the therapeutic group than in the prophylactic group (16.7% vs. 0.43%), but did not differ between the prophylactic group and the no-dissection group (0.43% vs. 0.65%). The tumor size did not influence nodal recurrence. Nodal recurrence preferentially occurred in ipsilateral mid-lower jugular nodes.

CONCLUSIONS

Patients who have PTMC presenting with palpable lymphadenopathy should have therapeutic node dissection. Prophylactic node dissection is not beneficial in those without palpable lymphadenopathy.

Mediastinal lymph node involvement as the initial manifestation of occult thyroid cancer in the surgical treatment of lung cancer: report of a case

A 63-year-old man was referred to our institute for the treatment of squamous cell carcinoma of the upper lobe of his right lung. A right upper lobectomy of the lung was performed with a mediastinal lymph node dissection. The postoperative pathological examination of the dissected specimens revealed one of the superior mediastinal lymph nodes to be morbid with micrometastasis of occult thyroid cancer, while no node involvement was seen due to lung cancer. A right lobectomy of the thyroid gland with a modified radical neck dissection was done 4 years later after the confirmation of the absence of any recurrent sign of lung cancer. In the resected specimen, papillary thyroid microcarcinoma was observed with several intraglandular metastases and right regional lymph node involvement. Eight months later, a new primary lung cancer developed in the left lung, and a left upper lobectomy of the lung with a mediastinal lymph node dissection was performed. At that time, the absence of mediastinal lymph node metastasis from lung cancer or thyroid cancer was confirmed. Mediastinal lymph node involvement as the initial manifestation of occult thyroid cancer in surgical treatment for lung cancer is rare, but it is important to be aware of the possibility of incidentally detecting occult thyroid cancer in surgical dissections in this area for lung cancer. The appropriate surgical treatment should be determined while carefully considering the prognosis of the lung cancer as well as that of any coexisting malignancy.

Papillary microcarcinoma of the thyroid gland

Papillary microcarcinomas are a specific subgroup of papillary thyroid cancer. They have the same histological features as papillary thyroid cancer but are 1.0 cm or less in diameter. These tumours are a common incidental finding at autopsy and in thyroid glands excised for other pathology. This tumour can metastasize to regional lymph nodes but its ability to cause significant morbidity and mortality has been questioned. As papillary microcarcinomas can represent up to 30 per cent of all papillary cancers seen in a thyroid surgeon's practice, they are an important group. The aim of this review article is to outline the natural history of papillary microcarcinoma and to offer therapeutic management strategies.