Diffuse sclerosing variant of papillary carcinoma of the thyroid: ultrasound features with histopathological correlation

Sonographic characteristics of diffuse sclerosing variant of papillary thyroid carcinoma with histopathological correlation: a preliminary study

BACKGROUND

Diffuse sclerosing variant of papillary thyroid carcinoma (DSVPTC) is a rare but high invasive subtype of papillary thyroid carcinoma, which mandates an aggressive clinical strategy. Few studies have focused on the sonographic characteristics of DSVPTC and the role of ultrasound in diagnosis and treatment of this variant remains unknown. This study aimed to identify and understand DSVPTC more accurately under ultrasound in correlation with pathology.

METHODS

The ultrasound characteristics and histopathologic sections of 10 lesions in 10 DSVPTC patients who underwent thyroid surgery at our center between 2014 and 2020 were reviewed and compared with 184 lesions in 168 classic variant of papillary thyroid carcinoma (cPTC) patients.

RESULTS

6 DSVPTC cases (60%) showed the "snowstorm" pattern on sonogram and 4 cases (40%) presented hypoechoic solid nodules only. Vague borders (100.0% vs. 18.5%, P = 0.019) and abundant microcalcifications (66.7% vs. 10.9%, P = 0.037) were more common in DSVPTC nodules than in cPTC nodules, corresponding to the infiltrating boundaries and numerous psammoma bodies under the microscope respectively. Most of the DSVPTC cases had a heterogeneous background (80%) and suspicious metastatic cervical lymph nodes (80%) on sonograms. All DSVPTC cases had histopathological metastatic cervical lymph nodes.

CONCLUSION

The sonographic "snowstorm" pattern indicated DSVPTC with whole-lobe occupation. Hypoechoic solid nodules with vague borders and abundant microcalcifications on sonogram suggested DSVPTC lesion with an ongoing invasion. Regardless of which of the two sonograms was shown, the corresponding DSVPTC lesions were aggressive and required the same attention from the surgeons.

Aggressive subtypes of papillary thyroid carcinoma smaller than 1 cm

PURPOSE

Tumor size is important in determining the range of surgery in papillary thyroid carcinomas (PTCs), especially those smaller than 1 cm. We aimed to analyze the features of small PTCs with aggressive subtypes based on histological characteristics.

METHODS

In this retrospective study, we reviewed the medical records of 11,570 patients with PTCs ≤ 1 cm who underwent thyroidectomy between January 2009 and December 2016. Aggressive subtypes included diffuse sclerosing, solid, tall cell, columnar cell, and hobnail subtypes.

RESULTS

Among the 11,570 patients with PTCs ≤ 1 cm, 177 aggressive PTC subtypes were identified. Propensity score matching revealed 110 tumors (62.1%) with extrathyroidal extension of aggressive PTC subtypes and 451 (51.1%) non-aggressive PTC subtypes (95% confidence interval [CI], 0.41-0.80, P < 0.001). Metastatic central and lateral neck lymph nodes constituted 3.06 ± 3.67 and 3.81 ± 5.39 of aggressive PTC subtypes and 1.22 ± 2.14 and 2.85 ± 3.79 of non-aggressive PTC subtypes, respectively (central neck nodes: 95% CI, 1.42-2.26, P < 0.001; lateral neck nodes: 95% CI, 2.9-5.90, P < 0.001). Seven patients with aggressive PTC subtypes (3.95%) and 12 with non-aggressive PTC subtypes (1.7%) exhibited recurrence.

CONCLUSION

Aggressive subtypes of small PTC tumors ≤ 1 cm exhibited more extrathyroidal extension and neck node metastasis. This study suggests that surgeons should consider the aggressive subtypes as important factors when deciding the range of surgery in PTCs smaller than 1 cm.

Differential diagnosis of diffuse sclerotic thyroid papillary carcinoma and Hashimoto's thyroiditis using fine-needle aspiration cytology, BRAFV600E , and ultrasound elastography

BACKGROUND

The diffuse sclerosing variant of papillary thyroid carcinoma (DSV-PTC) has ultrasound findings that are similar to Hashimoto's thyroiditis (HT), resulting in under-diagnosis. DSV-PTC combined with HT is also common, so early and accurate diagnosis of DSV-PTC using a variety of diagnostic techniques, including FNAC, BRAF^V600E mutation detection, and ultrasound elastography, is critical.

OBJECTIVE

To assess the diagnostic value of fine-needle aspiration cytology (FNAC) and BRAF^V600E detection in combination with ultrasound elastography in the diagnosis of DSV-PTC.

METHODS

We performed a retrospective analysis of 40 patients with pathologically confirmed DSV-PTC and 43 patients with HT admitted to our hospital's ultrasound department between January 2015 and December 2020. Preoperative FNAC, BRAF^V600E mutation detection, and ultrasound elastography imaging were all performed on all patients. For a definitive diagnosis, the results of these tests were compared to postoperative pathological findings. The diagnostic value of FNAC, BRAF^V600E mutation detection, ultrasound elasticity imaging, and their combination for DSV-PTC diagnosis was assessed.

RESULTS

The mean elastic strain rate ratio (E1/E2) of the 40 DSV-PTC cases was 5.75 ± 2.14, while that of the 43 HT cases was 2.81 ± 1.20. The receiver operating characteristic (ROC) curve was generated using the average value of E2/E1. The area under the ROC curve was 0.910, and the optimal E2/E1 cut-off value was 4.500. When FNAC, BRAF^V600E mutation detection, and ultrasound elasticity imaging detection were combined, the diagnostic sensitivity, specificity, negative predictive value, positive predictive value, and accuracy of DSV-PTC diagnosis were 92.5%, 95.3%, 93.2%, 94.9%, and 94.0%, respectively, which were significantly higher than the single technique (p < 0.05).

CONCLUSIONS

The use of FNAC, BRAF^V600E mutation detection, and ultrasound elastography in combination is more helpful in establishing an accurate diagnosis of DSV-PTC than using a single diagnostic technique alone.

Thyroid papillary carcinoma with the 'snowstorm appearance': a clinicopathological analysis of three cases

This current case report presents the detailed clinicopathological analysis of three patients with papillary thyroid carcinoma, each of which presented with the ‘snowstorm appearance’ on ultrasonography. Ultrasonography of this tumour typically shows a diffusely enlarged thyroid with hypoechoic and heterogeneous internal echoes, and diffusely scattered microcalcifications, which form the ‘snowstorm appearance’. Microscopically, case 1 had a large number of psammoma bodies, infiltration of lymphocytes, formation of lymphatic follicles and extensive squamous metaplasia, leading to the diagnosis of a diffuse sclerosing variant of papillary thyroid carcinoma (DSVPTC). Case 2 was diagnosed with follicular papillary thyroid carcinoma. Their tumour had numerous calcifications in the stroma and follicles. Case 3 was diagnosed with a multifocal papillary thyroid carcinoma in the background of Hashimoto's thyroiditis. Their tumour showed calcification in the stroma and follicles, together with cervical lymph node metastasis. DSVPTC is a rare variant of thyroid papillary carcinoma. It has the ‘snowstorm appearance’ on ultrasound, but this can also be found in follicular papillary carcinoma and multifocal thyroid papillary carcinoma. Papillary thyroid carcinoma with the ‘snowstorm appearance’ has a large number of peripheral lymph nodes metastases, thus requiring radical surgery and postoperative adjuvant therapy.

Imaging of the Thyroid: Practical Approach

Imaging evaluation of the thyroid gland spans a plethora of modalities, including ultrasound imaging, cross-sectional studies, and nuclear medicine techniques. The overlapping of clinical and imaging findings of benign and malignant thyroid disease can make interpretation a complex undertaking. We aim to review and simplify the vast current literature and provide a practical approach to the imaging of thyroid disease for application in daily practice. Our approach highlights the keys to differentiating and diagnosing common benign and malignant disease affecting the thyroid gland.

Pulmonary adenocarcinoma with psammoma bodies is associated with a specific endobronchial ultrasound pattern and a high prevalence of actionable driver mutations

INTRODUCTION

Pulmonary adenocarcinoma with psammoma bodies (PAPBs) is a rare histological variant whose association with a high prevalence of targetable mutations has been suggested by scant literature reports describing small series. We aim to describe the endobronchial ultrasound (EBUS) pattern and the molecular profile by next-generation sequencing of an Italian series of patients with PAPBs.

MATERIAL AND METHODS

Over a 8-year period (2012-2019), we identified 15 patients with a very uncommon endobronchial ultrasound (EBUS) heterogeneity pattern characterized by the presence of multiple to countless, punctate non-shadowing foci ("starry sky" sign) which were not evident at CT and corresponded to psammoma bodies at pathological examination. The clinical, radiological, pathological and molecular findings of these patients were retrieved and analyzed.

RESULTS

Pathological examination of the EBUS-TBNA specimens revealed malignancy (12 pulmonary adenocarcinoma, 2 breast carcinoma, 1 colonic carcinoma) and showed the presence of psammoma bodies in all of the 15 patients with the starry sky sign. Among the 12 patients with pulmonary adenocarcinoma with psammoma bodies, female sex (8/12, 66.7 %) and never-smoking habit (6/12, 50 %) were prevalent. Molecular tumor profiling using the Oncomine™ Focus DNA and RNA fusion panels was successfully performed in 11/12 patients and revealed 10 genetic alterations (BRAF mutation, 4; EGFR mutation, 2; ALK rearrangement, RET rearrangement, PIK3CA mutation, CDK4 amplification 1) in 7 patients (63.6 %).

CONCLUSION

The present series suggests that pulmonary adenocarcinoma with psammoma bodies is associated with a readily identifiable EBUS pattern and with a high prevalence of different, often uncommon and actionable, driver mutations.

Thyroid Cancer in the Pediatric Population

Thyroid cancer is rare in the pediatric population, but thyroid carcinomas occurring in children carry a unique set of clinical, pathologic, and molecular characteristics. In comparison to adults, children more often present with aggressive, advanced stage disease. This is at least in part due to the underlying biologic and molecular differences between pediatric and adult thyroid cancer. Specifically, papillary thyroid carcinoma (which accounts for approximately 90% of pediatric thyroid cancer) has a high rate of gene fusions which influence the histologic subtypes encountered in pediatric thyroid tumors, are associated with more extensive extrathyroidal disease, and offer unique options for targeted medical therapies. Differences are also seen in pediatric follicular thyroid cancer, although there are few studies of non-papillary pediatric thyroid tumors published in the literature due to their rarity, and in medullary carcinoma, which is most frequently diagnosed in the pediatric population in the setting of prophylactic thyroidectomies for known multiple endocrine neoplasia syndromes. The overall shift in the spectrum of histotypes and underlying molecular alterations common in pediatric thyroid cancer is important to recognize as it may directly influence diagnostic test selection and therapeutic recommendations.

Special types of thyroid carcinoma

This article reviews the small percentage of thyroid tumours that are not classified as classic papillary thyroid carcinoma, follicular thyroid carcinoma, and medullary thyroid carcinoma. It includes subtypes of papillary thyroid carcinoma, including, tall-cell, hobnail/micropapillary, columnar cell, diffuse sclerosing and solid variants. Poorly differentiated carcinoma, high-grade carcinoma and anaplastic thyroid carcinoma are reviewed. Also discussed are entities that are unusual but need to be recognized as primary thyroid neoplasms, i.e. mucoepidermoid carcinoma, sclerosing mucoepidermoid carcinoma with eosinophilia, and mammary analogue secretory carcinoma/secretory carcinoma. The pathological features and prognostic factors are described; a brief review of molecular correlates of these neoplasms is included.

AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS, AMERICAN COLLEGE OF ENDOCRINOLOGY, AND ASSOCIAZIONE MEDICI ENDOCRINOLOGI MEDICAL GUIDELINES FOR CLINICAL PRACTICE FOR THE DIAGNOSIS AND MANAGEMENT OF THYROID NODULES--2016 UPDATE

Thyroid nodules are detected in up to 50 to 60% of healthy subjects. Most nodules do not cause clinically significant symptoms, and as a result, the main challenge in their management is to rule out malignancy, with ultrasonography (US) and fine-needle aspiration (FNA) biopsy serving as diagnostic cornerstones. The key issues discussed in these guidelines are as follows: (1) US-based categorization of the malignancy risk and indications for US-guided FNA (henceforth, FNA), (2) cytologic classification of FNA samples, (3) the roles of immunocytochemistry and molecular testing applied to thyroid FNA, (4) therapeutic options, and (5) follow-up strategy. Thyroid nodule management during pregnancy and in children are also addressed. On the basis of US features, thyroid nodules may be categorized into 3 groups: low-, intermediate-and high-malignancy risk. FNA should be considered for nodules ≤10 mm diameter only when suspicious US signs are present, while nodules ≤5 mm should be monitored rather than biopsied. A classification scheme of 5 categories (nondiagnostic, benign, indeterminate, suspicious for malignancy, or malignant) is recommended for the cytologic report. Indeterminate lesions are further subdivided into 2 subclasses to more accurately stratify the risk of malignancy. At present, no single cytochemical or genetic marker can definitely rule out malignancy in indeterminate nodules. Nevertheless, these tools should be considered together with clinical data, US signs, elastographic pattern, or results of other imaging techniques to improve the management of these lesions. Most thyroid nodules do not require any treatment, and levothyroxine (LT4) suppressive therapy is not recommended. Percutaneous ethanol injection (PEI) should be the first-line treatment option for relapsing, benign cystic lesions, while US-guided thermal ablation treatments may be considered for solid or mixed symptomatic benign thyroid nodules. Surgery remains the treatment of choice for malignant or suspicious nodules. The present document updates previous guidelines released in 2006 and 2010 by the American Association of Clinical Endocrinologists (AACE), American College of Endocrinology (ACE) and Associazione Medici Endocrinologi (AME).

Papillary Thyroid Carcinoma Arising in Children and Adolescent Hashimoto's Thyroiditis: Ultrasonographic and Pathologic Findings

Objectives. We compared the ultrasonography and pathology features of papillary thyroid carcinoma (PTC) in pediatric and adolescents with Hashimoto's thyroiditis (HT) with those of non-HT patients. Materials and Methods. Eleven patients who were surgically confirmed to have pediatric or adolescent PTC from 2006 to 2014 were included in this study. We retrospectively analyzed the preoperative ultrasonography and pathology features of PTC arising in HT and non-HT patients. Results. On ultrasonography, thyroid gland was lobulated and enlarged, with many scattered microcalcifications in four of five HT patients. Four of six non-HT patients had suspicious masses with calcifications. The diffuse sclerosing variant of PTC (DSVPTC) was found in three of five HT patients, but none in non-HT patients. Macroscopic or microscopic extrathyroidal extension was evident in all of the HT patients and four of the non-HT patients. Neck lymph node metastases were in all HT patients and five of non-HT patients. Conclusions. Three of five PTCs in pediatric and adolescent HT patients were DSVPTC, whereas all PTCs of the non-HT patients were classic type. On ultrasonography, thyroid gland was diffusely enlarged with scattered microcalcifications in four of five HT patients. All five HT cases had aggressive disease, including extrathyroidal extension and cervical lymph node metastases.

Computerized analysis of calcification of thyroid nodules as visualized by ultrasonography

OBJECTIVE

The purpose of this study is to quantify computerized calcification features from ultrasonography (US) images of thyroid nodules in order to determine the ability to differentiate between malignant and benign thyroid nodules.

METHODS

We designed and implemented a computerized analysis scheme to quantitatively analyze the US features of the calcified thyroid nodules from 99 pathologically determined calcified thyroid nodules. Univariate analysis was used to identify features that were significantly associated with tumor malignancy, and neural-network analysis was performed to classify tumors as benign or malignant. The diagnostic performance of the neural network was evaluated using receiver operating characteristic (ROC) analysis, where in the area under the ROC curve (Az) summarized the diagnostic performance of specific calcification features.

RESULTS

The performance values for each calcification feature were as follows: ratio of calcification distance=0.80, number of calcifications=0.68, skewness=0.82, and maximum intensity=0.75. The combined value of the four features was 0.84.With a threshold of 0.64, the Az value of calcification features was 0.83 with a sensitivity of 83.0%, specificity of 82.4%, and accuracy of 82.8%.

CONCLUSIONS

These results support the clinical feasibility of using computerized analysis of calcification features from thyroid US for differentiating between malignant and benign nodules.

Sonographic and cytopathologic correlation of papillary thyroid carcinoma variants

Papillary thyroid carcinoma (PTC) is the most common thyroid cancer and constitutes more than 70% of thyroid malignancies. Although TNM staging is the most widely used parameter for determination of therapeutic plans, recent studies have suggested that different histopathologic variants of PTC can also have different clinical courses and patient prognoses. Sonographic criteria for PTC are well established and include a taller-than-wide shape, an irregular margin, microcalcifications, and marked hypoechogenicity. The role of sonography has expanded to enable the characterization of PTC variants based on their sonographic features. Tall cell and diffuse sclerosing variants appear to have more aggressive clinical courses with unfavorable prognoses, whereas the more recently described cribriform-morular and Warthin-like variants have relatively indolent clinical courses. The prognoses of patients with follicular, solid, columnar cell, and oncocytic variants are still controversial and may be similar to the prognosis of conventional PTC. Understanding the sonographic characteristics of PTC variants with clinicopathologic correlation may be helpful for suggesting an appropriate treatment plan.

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.

Diffuse sclerosing variant of papillary thyroid carcinoma: sonography and specimen radiography

The purpose of this pictorial essay is to show the limitations of sonography and complementary usefulness of specimen radiography in detecting microcalcifications of the diffuse sclerosing variant of papillary thyroid carcinoma, which mostly manifests as diffusely scattered microcalcifications in the thyroid gland.

Diffuse sclerosing variant of papillary thyroid carcinoma with multiple metastases and elevated serum carcinoembryonic antigen level

BACKGROUND

Diffuse sclerosing variant of papillary thyroid carcinoma (DSPC) is a rare variant of papillary thyroid carcinoma (PTC). We report a 61-year-old female of DSPC whose course was complicated by multiple metastases and an elevated serum carcinoembryonic antigen (CEA) level.

SUMMARY

The patient presented with upper back pain. X-ray showed an osteolytic lesion of the sixth cervical spinous process. She had a hard, nonmovable mass with fixed enlarged lymph nodes (LNs) over right neck. Fine-needle aspiration cytology revealed PTC with LNs metastasis. Positron emission tomography demonstrated multiple brain, bone, liver, and lung metastases. However, the patient had an elevated serum CEA level. She underwent a total thyroidectomy and 200 mCi radioactive (131)I therapy. The pathological findings were diffuse sclerosing variant of PTC with capsular and lymph vessel invasion. A double staining of tumor specimen appeared concomitantly positive for CEA and thyroglobulin.

CONCLUSIONS

To our knowledge, DSPC with an elevated CEA level is extremely rare.

Diffuse sclerosing variant of thyroid papillary carcinoma: diagnostic challenges occur with Hashimoto's thyroiditis

Diffuse sclerosing papillary thyroid carcinoma (DSPTC) is a relatively rare variant of papillary thyroid carcinoma with distinct histological features, radiological characteristics, and biological aggressiveness. Compared with conventional papillary thyroid carcinoma, DSPTC is characterized by scattered microscopic tumor islands, diffuse fibrosis, calcification, and abundant lymphocytic aggregation. A preoperative diagnosis is challenging in the absence of nodules and scanty fine needle aspiration cytology samples. We describe a unique DSPTC patient, an 18-year-old woman who presented with a neck mass that grew slowly for 2 years. The palpable neck mass was nontender, well defined, firm, and unmovable. Laboratory studies showed normal thyroid function and positive autoimmune markers: antithyroglobulin antibody = 1:1600 and antimicrosomal antibody = 1:1600. A neck ultrasound showed diffusely prominent microcalcifications with one small vague nodule. Hashimoto's thyroiditis with an accompanying malignancy was suspected. Based on the result of intraoperative pathology reports, the patient was given a total thyroidectomy. Lymph node dissection and histological analysis revealed bilateral DSPTC in addition to lymphocytic thyroiditis in nonmalignant areas of the thyroid. Clinical and histological diagnostic challenges usually occur when DSPTC presents with a diffuse thyroid enlargement, dispersed microscopic tumor islands (frequently without mass formation), extensive fibrosis, and abundant lymphocytic infiltration mimicking thyroiditis.

Sonographic findings of the diffuse sclerosing variant of papillary carcinoma of the thyroid

OBJECTIVE

The purpose of this series was to describe the sonographic findings of the diffuse sclerosing variant of papillary carcinoma (DSVPC) of the thyroid.

METHODS

The sonographic findings of 8 patients with DSVPC of the thyroid were retrospectively analyzed. The following sonographic features of DSVPC of the thyroid were analyzed: extent of disease, echogenicity, microcalcifications, and cervical metastatic lymphatic nodes.

RESULTS

Three of 8 cases were unilateral, and 5 were bilateral. All 8 cases showed diffuse involvement of at least 1 entire thyroid lobe. Five of 8 cases showed hyperechogenicity, and 3 showed hypoechogenicity. Seven of 8 cases showed diffuse scattered microcalcifications, and 1 showed locally distributed microcalcifications. All 8 cases showed cervical metastatic lymph nodes.

CONCLUSIONS

The sonographic findings of DSVPC of the thyroid are characteristic, and sonography is a useful imaging tool in diagnosis of DSVPC of the thyroid.

Value of specimen radiographs in diagnosing multifocality of thyroid cancer

BACKGROUND

Specimen radiography has been used widely to evaluate the complete excision of calcified breast lesions but has not been evaluated for thyroid cancer.

METHODS

Specimen radiographs were evaluated retrospectively to identify additional cancers that were demonstrated only as calcifications. Receiver operating characteristic curve analysis was performed to compare the combination of specimen radiography and ultrasonography versus ultrasonography alone for detecting multifocality.

RESULTS

Some 122 thyroid cancer specimens were obtained from 122 patients between January and April 2008. Specimen radiography detected 27 cancers (18.5 per cent) not detected by ultrasonography. Diagnoses were changed after evaluation of specimen radiographs in three of these patients. The area under the curve of the combination of specimen radiography and ultrasonography was significantly higher than that of ultrasonography alone (P = 0.005).

CONCLUSION

Specimen radiography is a potentially useful tool for diagnosing cancer type and predicting the extent of thyroid cancer.

New clinical features of thyroid cancer in eastern China

OBJECTIVE

Analyze recent clinical features of thyroid cancer in eastern China.

METHODS

Investigation and comparison of clinical data of thyroid cancer patients from 1996 to 2006 from the Department of Head and Neck Surgery in the Cancer Hospital of Fudan University, Shanghai, China.

RESULTS

The number of patients with thyroid cancer rose from 148 in the year 1996 to 572 in the year 2006, a 3.9-fold increase. Routine ultrasound survey during physical examination revealed four cases (2.7%) in 1996 and 285 cases (49.8%) in 2006. The sensitivity of the ultrasound survey in thyroid cancer diagnosis was 86.66% in 1996 and 88.20% in 2006 (P>0.05). Papillary carcinoma was most prevalent (87.8% in 1996 and 92.8% in 2006). An increasing proportion of small tumors was found. The incidence of microcarcinoma was 35.7% in 2006 in contrast with 20.3% in 1996 (P<0.01). Moreover, tumors with diameter from 1 to 2 cm were found in 38.5% patients in 2006 as opposed to 27.0% in 1996 (P<0.01). Extrathyroid extension was reported in 46 (31.1%) patients in 1996, but only in 39 (6.8%) in 2006 (P<0.01). Central cervical lymph node metastases were found in 98 (66.2%) patients in 1996, contrasting with 301 (52.6%) in 2006 (P<0.05). Thirty-seven (25.0%) patients had lateral cervical lymph node metastasis in 1996 compared with 117 (20.5%) in 2006 (P>0.05). Last, the proportion of stage I cancers in 2006 was higher than that in 1996.

CONCLUSION

With the increasing incidence of thyroid cancer, cancer was discovered at an earlier stage. This is due to new clinical features of thyroid cancer, such as the decrease in tumor diameter, the lower rate of extrathyroid extension and of cervical lymph node metastasis. Routine ultrasound survey during physical examination has become the most common way to detect thyroid cancer. Increasing usage of diagnostic scrutiny, including the ultrasound survey, has most likely contributed to the increased incidence through detection of small thyroid cancers. Increased use of ultrasound to screen thyroid cancer in early stages should lead to better therapeutic outcome.