Diffuse sclerosing variant of papillary thyroid carcinoma: a clinicopathologic and immunophenotypic analysis of 22 cases

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.

Clinicopathological analysis of thyroid carcinomas with the RET and NTRK fusion genes: characterization for genetic analysis

Thyroid carcinomas exhibit various genetic alterations, including the RET and NTRK fusion genes that are targets for molecular therapies. Thus, detecting fusion genes is crucial for devising effective treatment plans. This study characterized the pathological findings associated with these genes to identify the specimens suitable for genetic analysis. Thyroid carcinoma cases positive for the fusion genes were analyzed using the Oncomine Dx Target Test. Clinicopathological data were collected and assessed. Among the 74 patients tested, 8 had RET and 1 had NTRK3 fusion gene. Specifically, of the RET fusion gene cases, 6 exhibited "BRAF-like" atypia and 2 showed "RAS-like" atypia, while the single case with an NTRK3 fusion gene presented "RAS-like" atypia. Apart from one poorly differentiated thyroid carcinoma, most cases involved papillary thyroid carcinomas (PTCs). Primary tumors showed varied structural patterns and exhibited a high proportion of non-papillary structures. Dysmorphic clear cells were frequently observed. BRAF V600E immunoreactivity was negative in all cases. Interestingly, some cases exhibited similarities to diffuse sclerosing variant of PTC characteristics. While calcification in lymph node metastases was mild, primary tumors typically required hydrochloric acid-based decalcification for tissue preparation. This study highlights the benefits of combining morphological and immunohistochemical analyses for gene detection and posits that lymph node metastases are more suitable for genetic analysis owing to their mild calcification. Our results emphasize the importance of accurate sample processing in diagnosing and treating thyroid carcinomas.

Prevalence of Differentiated High-Grade Thyroid Carcinoma Among Well-Differentiated Tumors: A Systematic Review and Meta-Analysis

Background: The current edition of the World Health Organization (WHO) classification of endocrine tumors introduced grading for follicular cell-derived thyroid cancer. Tumors with necrosis and/or high mitotic count but not fulfilling the Turin criteria for poorly differentiated carcinoma will be reclassified as differentiated high-grade thyroid carcinoma (DHGTC). However, the impact of this reclassification has not been evaluated. In this study, we performed a systematic review and meta-analysis to estimate the prevalence of this new entry across thyroid tumor subtypes. Methods: In this systematic review and meta-analysis, studies reporting data on necrosis and/or mitoses in well-differentiated thyroid carcinoma (WDTC) were used to estimate the prevalence of DHGTC. Heterogeneity and potential publication bias were also evaluated. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed, and quality assessment was performed using a modification of the Newcastle-Ottawa scale. The study has been registered in the International Prospective Register of Systematic Reviews (PROSPERO, ID: CRD42022378716). Results: In clinically unselected patients, the prevalence of DHGTC in WDTC was 0.072 [95% confidence interval, CI, = 0.045-0.113]. The proportion of high-grade tumors greatly varied across growth patterns and subtypes. Overall, the prevalence of DHGTC was higher in follicular thyroid carcinoma (FTC; 0.146 [CI = 0.101-0.205]) than in papillary thyroid carcinoma (PTC; 0.059 [CI = 0.036-0.097]). Diffuse sclerosing, follicular, and classic subtype PTC had the lowest rates of high-grade features (i.e., 0.018 [CI = 0.004-0.084]; 0.036 [CI = 0.010-0.124]; and 0.042 [CI = 0.027-0.066], respectively), while a greater proportion of solid trabecular and histologically aggressive PTC could be reclassified as DHGTC (i.e., 0.154 [CI = 0.067-0.314] and 0.168 [CI = 0.108-0.252], respectively). Similar proportions were obtained for minimally and widely invasive FTC (i.e., 0.136 [CI = 0.058-0.287] and 0.152 [CI = 0.086-0.254], respectively). Finally, in a cohort of patients with poor prognosis (i.e., fatal cases, metastatic and radioiodine resistant tumors, cases with biochemical recurrence), the proportion of DHGTC was 0.287 [CI = 0.155-0.469]. Conclusions: Following the current WHO indications, some tumors will be reclassified as DHGTC. The proportion of tumors with high-grade features is relevant in FTC, solid trabecular, and histologically aggressive PTC subtypes. A remarkable enrichment in DHGTC among patients with poor prognosis confirms the negative impact of high-grade features on outcome.

Diffuse Sclerosing Variant of Papillary Thyroid Carcinoma Is Related to a Poor Outcome: A Comparison Study Using Propensity Score Matching

OBJECTIVE

The clinical outcome of diffuse sclerosing variant of papillary thyroid carcinoma (DSV-PTC) remains controversial. We aimed to determine whether DSV-PTC is associated with an increased risk of persistent/recurrent disease.

METHODS

We performed a retrospective cohort study of DSV-PTC and classic variant of papillary thyroid carcinoma (CV-PTC) after postoperative radioactive iodine therapy. We used propensity score matching (1:3 matching ratio) to account for differences between the recipients of DSV-PTC and CV-PTC. Univariate and multivariate analyses were performed to assess the independent factors for persistent/recurrent disease. The Kaplan-Meier curve analyses were used to compare disease-free survival (DFS).

RESULTS

In total, 35 (12.7%) patients with DSV-PTC and 240 (87.3%) patients with CV-PTC were included. After propensity score matching, 35 pairs of patients were selected (DSV-PTC, n = 35; CV-PTC, n = 105). In the matched analysis, a higher proportion of patients with DSV-PTC experienced persistent/recurrent disease than that of those with CV-PTC (25.7% vs 5.7%, P = .003). In the multivariate analyses of clinical and tumor characteristics, only the histologic type of DSV-PTC (odds ratio, 6.288; 95% confidence interval, 1.900-20.811; P = .003) was associated with an increased risk of persistent/recurrent disease. The 5-year DFS rates for the DSV-PTC and CV-PTC groups were 69.2% and 93.6%, respectively. The Kaplan-Meier analysis indicated that the DSV-PTC group (P= .001) had shorter DFS.

CONCLUSION

This propensity score-matched analysis found that the histologic type of DSV-PTC may increase the risk of persistent/recurrent disease.

Clinicopathologic and Prognostic Features of Pediatric Follicular Cell-derived Thyroid Carcinomas: A Retrospective Study of 222 Patients

Pediatric thyroid carcinomas (TCs) are rare and mainly approached based on data extrapolated from adults. We retrospectively reviewed 222 pediatric TCs (patient age less than or equal to 21 y). Lymph node (LN) disease volume at presentation was considered high if the largest positive LN measured ≥1 cm and/or >5 LNs were positive. High-grade follicular cell-derived thyroid carcinoma (HGFCTC) were defined by the presence of marked mitotic count and/or tumor necrosis and considered as high-risk histology along with papillary thyroid carcinomas (PTC) diffuse sclerosing variant (DSV). Disease-free survival (DFS) was analyzed. LN involvement at presentation was significantly associated with male sex, larger tumor size, lymphatic invasion, positive surgical margins, and distant metastases at presentation. Five- and 10-year DFS was 84% and 77%, respectively. Only 1 patient with HGFCTC died of disease. Within PTC variants, PTC-DSV was associated with adverse histopathologic parameters and higher regional disease spread, unlike PTC tall cell variant which did not portend worse behavior. The presence of necrosis conferred worse DFS ( P =0.006), while increased mitotic activity did not. While the entire HGFCTC group did not correlate with outcome ( P =0.071), HGFCTC with necrosis imparted worse DFS ( P =0.006). When restricted to PTC-DSV and HGFCTC with necrosis, high-risk histologic classification emerged as an independent prognostic parameter of DFS ( P =0.020). The excellent prognosis of pediatric TCs differs from that of adult TCs showing similar histologic features. While neither increased mitotic activity nor PTC tall cell variant histology predict adverse outcome, PTC-DSV and tumors with necrosis constitute high-risk histologic variants with an increased risk of protracted disease.

Autoimmune Thyroiditis and Risk of Malignancy in Children with Thyroid Nodules

Background: It is uncertain whether the presence of autoimmune thyroiditis (AIT) increases the risk of thyroid cancer in children with thyroid nodules. This study evaluated the association between AIT and thyroid cancer in pediatric patients with thyroid nodules. Methods: A cross-sectional study was performed of pediatric patients (<19 years old) with a thyroid nodule (≥1 cm) who underwent fine-needle aspiration in an academic pediatric thyroid center. AIT was defined by the presence of thyroid autoantibodies or diffusely heterogeneous sonographic echotexture. The primary outcome was diagnosis of thyroid cancer. The association of AIT with thyroid cancer was evaluated with univariable and multivariable logistic regression. Associations of AIT with subject and nodule characteristics were also assessed. Results: Four hundred fifty-eight thyroid nodules in 385 patients (81% female) were evaluated at a median age of 15.5 years (interquartile range 13.5-17.0). Thyroid cancer was present in 108 nodules (24%). AIT was present in 95 subjects (25%) and was independently associated with an increased risk of thyroid cancer (multivariable odds ratio [OR] 2.19, 95% confidence interval [CI] 1.32-3.62). Thyroid cancer was also independently associated with younger age, nodule size, and solitary nodules, but was not associated with serum thyrotropin concentration. AIT was not associated with the likelihood of subjects undergoing thyroid surgery (p = 0.17). AIT was less commonly associated with follicular thyroid carcinoma than with papillary thyroid carcinoma (OR 0.22, CI 0.05-1.06). Among papillary thyroid carcinomas, AIT was strongly associated with the diffuse sclerosing variant (OR 4.74, CI 1.33-16.9). AIT was not associated with the extent of local, regional, or distant disease at thyroid cancer diagnosis. Conclusions: AIT is independently associated with an increased risk of thyroid cancer in children with thyroid nodules. These findings suggest that the evaluation of thyroid autoantibodies and thyroid echotexture may inform thyroid cancer risk assessment and surgical decision-making in children with thyroid nodules.

Comparison of the clinical characteristics of primary thyroid lymphoma and diffuse sclerosing variant of papillary thyroid carcinoma

OBJECTIVE

Both primary thyroid lymphoma (PTL) and diffuse sclerosing variant of papillary thyroid carcinoma (DSVPTC) are two rare malignant tumours with different therapies and prognoses. This study compared their clinical features.

METHODS

From a retrospective review of the pathologic database at our institute between January 2015 and August 2020, 52 PTL patients and 40 DSVPTC patients were included. Demographic, clinical, laboratory and ultrasound data were extracted from electronic medical records. Statistical analyses were performed using GraphPad Prism 5.0.

RESULTS

Both PTL and DSVPTC were more likely to occur in women (83.7 and 67.5%, respectively), but DSVPTC patients were younger (median age: 36 vs 64.5), had fewer compressive symptoms, and more frequently had neck lymph node metastasis than PTL patients. The prevalence of Hashimoto's thyroiditis (HT) and hypothyroidism was significantly higher in PTL patients than in DSVPTC patients (31% vs 17.5%). Hyperthyroidism could only be found in DSVPTC patients, which accounted for 7.5%. Heterogeneous echogenicity and irregular edges were frequently observed in both PTL and DSVPTC. However, compared with PTL, DSVPTC exhibited smaller lesion sizes, higher frequencies of diffuse sonographic patterns and calcification and lower frequencies of hypoechoic features and internal blood flow signal. The overall survival rate with PTL was 77.23%, which was lower than that with DSVPTC (90.91%), but this difference was not significant (P = 0.096).

CONCLUSION

Clinical characteristics such as age, compression symptoms, and sonographic features such as a large mass with heterogeneous echogenicity, hypoechoic, irregular edges, and calcification are helpful for impression diagnosis of PTL and DSVPTC before surgery.

Diffuse sclerosing variant of papillary thyroid carcinoma: outcomes of 33 cases

INTRODUCTION

Diffuse sclerosing variant of PTC (DSV-PTC) is an uncommon subtype of thyroid cancer. Although an aggressive behavior is often recognized, prognostic significance is still under debate.

OBJECTIVES

To describe the clinicopathological features and outcomes of a series of DSV-PTC patients.

METHODS

Retrospective data collection involving 33 patients diagnosed with DSV-PTC followed at the Endocrine Department of the Portuguese Institute of Oncology in Lisbon between 1981 and 2020.

RESULTS

Twenty-six patients (78.8%) were females with a mean age at presentation of 29.4 ± 11.7 years old. Mean time of follow-up was 19.5 ± 10.6 years (range 0.5-39). Histologically, bilateral tumors were present in 72.7% patients (n = 24), thyroid capsular invasion was documented in 57.6% (n = 19), 45.4% (n = 15) had extrathyroidal extension, and 42.4% (n = 14) had lymphovascular invasion. Most patients were staged pT3 (42.4%, n = 14) and pN1 (81.8%, n = 27). Median lymph nodes resected were 16. None of the patients showed distant metastases at presentation. All patients were treated at least once with 131I. During follow-up, four patients (14.8%), with persistent neck disease, were diagnosed with distant metastases, all of them in the lung. Two patients (1.8%) presented recurrent disease in the neck after being considered with no evidence of disease. At the last appointment, 18 patients (54.5%) were in remission, 4 (12.1%) had biochemical evidence of disease, 6 had structural disease, and for 5 patients disease status was considered as undetermined. There was no disease related mortality.

DISCUSSION/CONCLUSION

Our study confirms that DSV-PTC is diagnosed more often in young patients and exhibits a local extensive disease at presentation. On the other hand, even in the presence of distant metastases, no patient died during follow-up.

Updates in the Pathologic Classification of Thyroid Neoplasms: A Review of the World Health Organization Classification

Advances in medical sciences and evidence-based medicine have led to momentous changes in classification and management of thyroid neoplasms. Much progress has been made toward avoiding overdiagnosis and overtreatment of thyroid cancers. The new 2017 World Health Organization (WHO) classification of thyroid neoplasms updated the diagnostic criteria and molecular and genetic characteristics reflecting the biology and behavior of the tumors, and newly introduced the category of borderline malignancy or uncertain malignant potential. Some neoplasms were subclassified, renamed, or redefined as a specific entity. This review introduces changes in the fourth edition WHO classification of thyroid tumors and updates the contemporary diagnosis and classification of thyroid tumors. We also discuss several challenges with the proposal of new diagnostic entities, since they have unique histopathologic and molecular features and clinical relevance.

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.

Recent Advances in the Classification of Low-grade Papillary-like Thyroid Neoplasms and Aggressive Papillary Thyroid Carcinomas: Evolution of Diagnostic Criteria

Papillary thyroid carcinomas account for ∼80% of well-differentiated thyroid tumors. During the past decade, several new variants of papillary-like thyroid neoplasms and papillary thyroid carcinomas have been recognized. Some of these neoplasms that were previously classified as malignant have been reclassified as low-grade neoplasms, as the diagnostic criteria have evolved. Similarly, some of the papillary thyroid carcinomas that were previously classified as conventional or classic papillary thyroid carcinomas have now been recognized as more aggressive variants of papillary thyroid carcinomas. Recognizing these differences becomes more important for the proper medical, surgical, and radiotherapeutic management of patients with these neoplasms.

KIF5B/RET Rearrangement in a Carcinoma of the Thyroid Gland: A Case Report of a Fatal Disease

BACKGROUND

The diffuse sclerosing variant of papillary thyroid cancer (DSV-PTC) is a rare variant of papillary thyroid cancer (PTC) with different clinicopathological features compared with conventional PTC.

CASE

An advanced DSV-PTC was diagnosed in a 39-year-old man. The radioiodine posttherapeutic whole-body-scan showed only an uptake in the central neck, whereas the computerized tomography showed multiple latero-cervical and mediastinum lymph node metastases, a single and spiculated lung lesion and multiple bilateral cerebellum metastases. The patient died after 6 months from the initial diagnosis. The histological revision of the thyroid tumor confirmed the diagnosis of DSV-PTC, and its molecular analysis revealed a KIF5B/RET rearrangement that, until now, was described only in a minority of lung adenocarcinoma. Other 18 cases of DSV-PTC were then studied for the presence of KIF5B/RET rearrangement, but all of them were negative.

CONCLUSIONS

This was a case of DSV-PTC positive for KIF5B/RET rearrangement, but considering that this alteration has been described only in lung adenocarcinoma and that the clinical course was more typical of lung carcinoma, we cannot completely rule out the possibility that this was a metastatic lesion from a lung tumor mimicking a DSV-PTC. As an alternative, we can also hypothesize that this was a case of fusion of two tumoral tissues deriving from a DSV-PTC and a metastasis of a KIF5B/RET positive lung adenocarcinoma. The question of whether the molecular findings, particularly when specifically reported only in some subtypes of human tumors, can overcome the morphological diagnosis is a matter of discussion.

High endothelial venule-like vessels and lymphocyte recruitment in diffuse sclerosing variant of papillary thyroid carcinoma

Diffuse sclerosing variant of papillary thyroid carcinoma (DSPTC) is a rare subtype of papillary thyroid carcinoma with a high incidence of lymph node metastasis. One of its characteristic histological features is the presence of dense lymphocyte infiltrates; however, how these lymphocytes are recruited in this pathological setting remains unclear. Here, we analysed 17 DSPTC cases immunohistologically for cell adhesion molecules expressed on endothelial cells. We found that venules morphologically similar to high endothelial venules (HEVs) in secondary lymphoid organs were induced in lymphoid aggregates in DSPTC, and such HEV-like vessels expressed 6-sulfo sialyl Lewis X (sLeX) glycans as well as intercellular adhesion molecule 1 (ICAM-1). Triple immunohistochemistry revealed that CD8⁺ cytotoxic T cells were the major lymphocyte subset attached to the luminal surface of HEV-like vessels. sLeX-type glycans were also expressed on DSPTC carcinoma cells, which in binding assays were decorated with E-selectin•IgM chimaeras calcium-dependently. These findings collectively suggest that 6-sulfo sLeX glycans, together with ICAM-1, on HEV-like vessels may function to recruit CD8⁺ cytotoxic T cells in DSPTC. Additionally, sLeX-type glycans on carcinoma cells might partly contribute to highly metastatic properties of DSPTC through interaction with E-selectin expressed on endothelial cells.

Follicular and Diffuse Sclerosing Variant Papillary Thyroid Carcinomas as Independent Predictive Factors of Loco-Regional Recurrence: A Comparison Study Using Propensity Score Matching

BACKGROUND

Only about half of papillary thyroid carcinoma (PTC) cases are classified as conventional PTC (CV-PTC), whereas various histologic variants constitute the remaining cases. Since controversies about the clinical behavior and outcomes of PTC variants continue, the purpose of this study was to compare the outcomes of patients with PTC variants who were treated at a large tertiary referral center in Korea.

METHODS

The medical records for 15,598 CV-PTCs, 435 follicular variants of PTC (FV-PTCs), and 66 diffuse sclerosing variants of PTC (DSV-PTCs) were retrospectively reviewed. Loco-regional recurrences (LRR) among PTC variants were compared using propensity score matching.

RESULTS

Analysis I compared CV-PTC with FV-PTC. After rigorous matching, 367 pairs were established. Recurrence-free survival (RFS) rates in CV-PTC were 96.1% at 5 years, 92.2% at 10 years, and 92.2% at 15 years, while those for FV-PTC were 98.8% at 5 years, 98.8% at 10 years, and 98.8% at 15 years (p = 0.026). Analysis II compared CV-PTC with DSV-PTC. Rigorous matching yielded 56 pairs. RFS rates for CV-PTC were 87.4% at 5 years, 87.4% at 10 years, and 87.4% at 15 years, while those for DSV-PTC were 68.9% at 5 years, 57.5% at 10 years, and were not available at 15 years (p = 0.013).

CONCLUSIONS

Compared with CV-PTC, FV-PTC showed less aggressive behaviors and more favorable outcomes. However, DSV-PTC showed more aggressive behaviors and a less favorable outcome than CV-PTC did. Therefore, the management strategy and follow-up plan for PTC should be differentiated according to the histologic variant.

Evaluation and management of thyroid nodules in children

PURPOSE OF REVIEW

The review is focused on new information about the presentation and management of thyroid nodules in children and adolescents.

RECENT FINDINGS

Palpable thyroid nodules are uncommon in children but many children have nodules detected by radiologic imaging. How to evaluate them, when to suspect thyroid cancer, and how best to follow apparently benign nodules has become an area of great interest. The American Thyroid Association recently published treatment guidelines for children with thyroid nodules and cancers but much has been learned since that publication.

SUMMARY

Personal and family history, ultrasound features, and fine needle aspiration cytology are used to determine the risk of cancer in thyroid nodules, which are then managed according to cancer risk.

Shear wave elastography diagnosis of the diffuse sclerosing variant of papillary thyroid carcinoma: A case report

The present study aimed to report the shear wave elastography (SWE) findings in a patient with the diffuse sclerosing variant of papillary thyroid carcinoma (DSVPTC). Since patients with DSVPTC may present with typical clinicopathological features and initially appear to have Hashimoto's thyroiditis, a thorough clinical evaluation and an early diagnosis are important. A 20-year-old female patient presented with a 1-month history of a neck mass and sore throat. Conventional ultrasound and SWE were performed using an AIXPLORER system with 14-5 MHz linear transducer. The patient had undergone total thyroidectomy and bilateral neck lymph node dissection, and an intraoperative pathology consultation to confirm the malignancy of lymph node metastasis. Pathological diagnosis was DSVPTC in both lobes, with lymph node metastases in the bilateral neck. The clinical presentation and serological findings were all indicative of Hashimoto's thyroiditis. Thyroid ultrasonography revealed diffuse enlargement of the both lobes, heterogenous echogenicity without mass formation, diffuse scattered microcalcifications and poor vascularization. SWE revealed stiff values of the thyroid: The mean stiffness was 99.7 kpa, the minimum stiffness was 59.1 kpa and the maximum stiffness was 180.1 kpa. The maximum stiffness of the DSVPTC (180.1 kpa) was higher compared with the diagnostic criteria of malignant thyroid nodules (65 kPa). SWE may be considered as a novel and valuable method to diagnose DSVPC.

A Case Report Demonstrating How the Clinical Presentation of the Diffuse Sclerosing Variant of Papillary Thyroid Carcinoma Can Mimic Benign Riedel's Thyroiditis

A 44-year-old female presented with a two-month history of a neck mass, sore throat, hoarseness, and intermittent dysphagia. Examination revealed a "woody" hard swelling arising from the right lobe of the thyroid. Clinically this was felt to be classical Riedel's thyroiditis (RT). Thyroid ultrasound showed a diffusely enlarged, low echogenicity thyroid with a multinodular goitre. An abnormal nodule extending across the isthmus was noted. Following a nondiagnostic fine needle aspiration, an open core biopsy was performed. This showed dense sclerotic fibrosis punctuated by nodular mononuclear inflammatory cells, which obscured follicular epithelial cells consistent with a fibrosing thyroiditis (Riedel's thyroiditis). A biopsy of pretracheal lymph nodes showed a sclerotic process throughout the lymph nodes and nests of epithelium bands with squamous differentiation obscured by a fibrous process. These findings raised the differential diagnosis of diffuse sclerosing variant of papillary thyroid carcinoma (DSV-PTC) with metastasis to lymph nodes. A total thyroidectomy and pretracheal lymph node dissection were performed. The final histological diagnosis was DSV-PTC. When managing a patient with presumed RT it is important to consider malignancy in the differential. DSV-PTC is one of the more aggressive forms of thyroid cancer but with early diagnosis and appropriate treatment patients may have excellent outcomes.

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.

Update on anaplastic thyroid carcinoma: morphological, molecular, and genetic features of the most aggressive thyroid cancer

Anaplastic thyroid carcinoma (ATC) is the most aggressive form of thyroid cancer. It shows a wide spectrum of morphological presentations and the diagnosis could be challenging due to its high degree of dedifferentiation. Molecular and genetic features of ATC are widely heterogeneous as well and many efforts have been made to find a common profile in order to clarify its cancerogenetic process. A comprehensive review of the current literature is here performed, focusing on histopathological and genetic features.

Laryngotracheal presentation of anaplastic thyroid carcinoma with squamous differentiation: seven cases demonstrating an under-recognized diagnostic pitfall

AIMS

To describe a series of anaplastic thyroid carcinomas that mimicked primary head and neck squamous cell carcinoma (HNSCC) by virtue of both morphology and clinical presentation.

METHODS AND RESULTS

Seven cases were identified in a 15-year period where a biopsy of an airway lesion that appeared to be squamous cell carcinoma was, in fact, anaplastic thyroid carcinoma. The tumours had squamous and/or spindle cell morphology, with only the squamous component being apparent in the airway biopsy. Some tumours arose within metaplastic (n = 3) or atypical (n = 3) epithelium, supporting the diagnosis of a primary mucosal tumour. Positive PAX8 (n = 5) and TTF-1 (n = 4) staining was identified.

CONCLUSIONS

An endotracheal presentation of anaplastic thyroid carcinoma with squamous morphology may be misdiagnosed as a primary head and neck squamous cell carcinoma. PAX8 and TTF-1 expression are helpful in making the distinction, but the problem lies in suspecting a thyroid carcinoma in what appears to be a straightforward diagnosis of HNSCC.

Aggressive variants of follicular cell-derived thyroid carcinomas: a cytopathologist's perspective

Follicular cell-derived carcinomas of the thyroid gland comprise a heterogeneous group of malignant neoplasms of the thyroid gland with varied histologic appearance and molecular profiles. In most patients, these tumors represent relatively indolent neoplasms; however, certain subtypes/variants behave in an aggressive manner, and the recognition of this subset of tumors is essential because of their variable response to therapy and significant morbidity and mortality. Fine-needle aspiration is considered an essential tool for the diagnosis of suspicious thyroid nodules. In this review, the authors discuss the clinical, histologic, and molecular findings and the prognostic implications of aggressive thyroid neoplasms with emphasis on the characteristic cytomorphologic features on fine-needle aspiration smears.

Different CXCR4 expression according to various histologic subtype of papillary thyroid carcinoma

Functional chemokine (C-X-C motif) receptor 4 (CXCR4) is well known to be over-expressed in papillary thyroid carcinoma (PTC). The aim of this study was to evaluate whether or not the expression of CXCR4 is different by histological subtypes of PTC and to elucidate the relationship between the expression of CXCR4 and clinicopathologic factors. CXCR4 expression in 127 PTC samples was assessed using immunohistochemical staining. The expression of CXCR4 showed different patterns according to the histological subtype of PTC (p < 0.001). A strong expression of CXCR4 was observed more frequently in the poorly differentiated region of PTC (81.0 %) than in classical PTC (50.0 %). Strong CXCR4 expression was less frequently shown in follicular variant (33.9 %) and in diffuse sclerosing variant (14.3 %) of PTC. CXCR4 expression showed a distinct pattern according to the histological subtype of PTC although not associated with other clinicopathological parameters.

Estrogen receptor- and progesterone receptor-positive diffuse sclerosing variant of papillary thyroid carcinoma: a case report

The diffuse sclerosing variant of papillary thyroid carcinoma (DSV-PTC) is a relatively rare tumor. We herein report the case of young woman with DSV-PTC who developed cervical lymph node recurrence 7 years after the initial surgery. A 15-year-old female patient with no medical or family history of thyroid tumors developed a thyroid neoplasm in the right lobe. Right thyroidectomy and regional lymphadenectomy were performed, and the tumor was diagnosed as DSV-PTC. She was followed up as an outpatient. Seven years after the surgery, cervical lymph node recurrence developed. On microscopic examination, the thyroid tumor showed a papillary growth pattern with numerous psammoma bodies and distinct fibrosis. Immunohistochemically, the tumor cells were estrogen receptor and progesterone receptor positive with reduced membranous expression of E-cadherin and were intermingled with S-100-positive dendritic/Langerhans cells. DSV-PTC is characterized by a strong tendency for invasion and metastasis. Thus, accurate diagnosis is clinically important, and a morphological and immunohistochemical understanding of DSV-PTC is necessary.

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.

A diffuse sclerosing variant of papillary thyroid carcinoma: clinical and pathologic features and outcomes of 34 consecutive cases

BACKGROUND

The diffuse sclerosing variant of papillary thyroid carcinoma (DSPC) is a relatively rare variant of papillary thyroid cancer. Large studies of patients with DSPC have been infrequently performed, and controversy still exists concerning some DSPC features and outcomes. The aim of the present study was to retrospectively evaluate the clinicopathologic features and outcomes in a series of 34 consecutive patients with DSPC and to compare them with a larger group of 245 consecutive patients with the classic variant of papillary thyroid carcinoma (cPTC) that were evaluated in the same period.

PATIENTS AND METHODS

Clinical and histological features (sex, age, tumor size,multifocality, bilaterality, extra thyroid extension, and local and distant metastases) were recorded in all patients, as well as any persistent or recurrent disease and the patients' disease status at last observation. Patients with cPTC were classified as either low (122) or high risk (123). DSPC and high-risk patients were all treated with the same protocol, including ¹³¹I treatment. All patients were included in a Cox regression model analysis to investigate the effect of each variable on the hazard ratio.

RESULTS

As expected, multifocality, bilaterality, and extra thyroid extension were more frequently noted at presentation, and the pT1 category of TNM classification was less frequently noted in DSPC and high-risk patients with cPTC compared with low-risk patients with cPTC. No significant difference was found between patients with DSPC and those with high-risk cPTC, except that extra thyroid extension was found more frequently in the patients with DSPC. Using multivariate analysis, diffuse sclerosing variant was an independent variable for predicting a high risk of persistent and recurrent disease during initial follow-up. However, at a later time, and after further treatment, the disease status was not different between patients with DSPC and those with high-risk cPTC, and only the presence of distant metastases affected the final outcome.

CONCLUSIONS

DSPC is a thyroid papillary carcinoma variant characterized by high aggressiveness. In patients with DSPC, the outcome is worse than in patients with low-risk cPTC; and, at presentation, characteristics are somewhat worse than for patients with high-risk cPTC.At medium term, the outcome is similar to that observed in patients with high-risk cPTC, provided aggressive treatment is used (additional surgical intervention, when required, and/or ¹³¹I radiotherapy).

Aggressive variants of papillary thyroid carcinoma

A number of histologic variants of well-differentiated papillary carcinoma have been found to be associated with more aggressive tumor behavior. Tall cell, columnar cell, diffuse sclerosing, solid/trabecular, and insular variants of well-differentiated papillary thyroid cancer are all potentially more aggressive than conventional papillary thyroid cancer. When subjected to multivariate analysis, however, evidence that the histologic subtype of tumor is an independent predictor of outcome is weak. Rather, the aggressive variants tend to present with features recognized by other staging systems as associated with a worse prognosis, including higher histologic grade, extracapsular spread, large tumor size, and the presence of distant metastases. Prognosis is directly related to the presence of these features. The state of our knowledge is limited by the relatively small number of cases that have been studied. The presence of an aggressive variant of papillary carcinoma should alert the surgeon that he is dealing with a potentially aggressive tumor. Clinical treatment decisions should be based on the stage of the disease, influenced by the knowledge that the aggressive variants tend to be associated with higher risk factors. The surgeon must be prepared to perform at the first, or second stage, a total thyroidectomy, central compartment neck dissection, additional lymphadenectomy, and/or resection of invaded surrounding structures, and search for distant metastasis. Postoperative radioactive iodine should generally be administered for these variants as they will generally be intermediate to advanced tumors. The tall cell variant is often refractory to such treatment but may be susceptible to treatment targeted against BRAF mutation. External beam irradiation may be used in cases of incomplete resection.

Diffuse sclerosing variant is a major subtype of papillary thyroid carcinoma in the young

BACKGROUND

Pediatric thyroid cancer differs from adult thyroid cancer in presentation and outcome. Pediatric thyroid cancer has a higher recurrence rate and greater percentage of lymph node and pulmonary metastasis. The clinicopathologic characteristics of pediatric thyroid cancer according to the histologic subtype have not been reported, however. In this study, we determined the histological subtypes of pediatric thyroid cancer and analyzed other clinicopathologic characteristics.

METHODS

All patients with thyroid cancer who were admitted to Severance Hospital, Seoul, South Korea, were retrospectively reviewed; their age was <20 years at diagnosis, and they were seen between January 1995 and August 2008.

RESULTS

Sixty-eight patients were identified. The histologic types of thyroid carcinoma were papillary thyroid carcinoma (PTC) in 57 (83.8%), follicular carcinoma in 8 (11.8%), and poorly differentiated carcinoma in 3 (4.4%). There were 28 (41.2%) cases of diffuse sclerosing variant of papillary carcinoma (DSVPC), 26 (38.2%) of conventional PTC, 2 (2.9%) of follicular PTC, and 1 (1.5%) cribriform-morular PTC. In patients with PTC, there was a higher incidence of bilateral thyroid involvement (p = 0.003), extrathyroidal extension (p = 0.009), and lymph node involvement (p = 0.018), and lower recurrence-free survival (p = 0.032) in DSVPC than in non-DSVPC. Univariate regression analysis revealed that extrathyroidal extension (p = 0.025) and tumor size (p = 0.001) were positively associated with a shorter time to recurrence.

CONCLUSION

DSVPC is a major subtype of PTC in the young.

Thyroid cancer: is the incidence rise abating?

OBJECTIVE

The aim of the present study was to determine recent trends in thyroid cancer incidence rates and to analyze histopathological characteristics and geographical distribution.

METHODS

Histologically proven 5367 cases were collected over the period 1998-2006 in France from the Rhône-Alpes thyroid cancer registry. Geographical variations of incidence were analyzed using a mixed Poisson model.

RESULTS

The average incidence rates, age standardized to the world population, were 3.9/100,000 in men and 12.3/100,000 in women, higher than those previously reported in France. After an initial increase during the first 3 years, a steady level of incidence was observed for the period 2001-2006. The annual incidence rate of microcarcinomas was correlated with that of all cancers in men and women (r=0.78 and 0.89; P<0.01) respectively. Papillary microcarcinomas represented 38% of tumors and two-thirds of them measured less than 5 mm in diameter. They were fortuitously discovered after thyroidectomy for benign diseases in 64% of cases. Histological marks of aggressiveness differed according to the size of the tumor. Despite recent advances in diagnosis, 13% of tumors were diagnosed at advanced stage especially in men. Geographical distribution of incidence based on subregional administrative entities showed lower incidence rates in rural than in urban zones in men (relative rate: 0.72; 95% CI: 0.62-0.84) and women (relative rate: 0.85; 95% CI: 0.73-0.93).

CONCLUSION

The present study suggests that the rise in thyroid cancer incidence is now abating. It could reflect standardization in diagnostic procedures. Further studies, performed on a more prolonged period, are necessary to confirm these data.

Diffuse sclerosing variant of papillary thyroid carcinoma: lack of BRAF mutation but occurrence of RET/PTC rearrangements

Diffuse sclerosing variant of papillary thyroid carcinoma (PTC) is a rare tumour with a characteristic morphology as well as a strong preponderance for younger female patients. The T1799A missense mutation in exon 15 of the BRAF gene and RET/PTC rearrangement have been identified as the dominant genetic tumour initiation events in the pathogenesis of PTC leading to a constitutive activation of the RAS-RAF-MAPK pathway. In order to elucidate the pathogenesis of diffuse sclerosing variant of PTC, the prevalence of BRAF mutation and RET/PTC were determined by RT-polymerase chain reaction and DNA-sequence analysis in tumour samples of seven patients with this variant (all female, age range 15-61 years, mean 33.3 years) without prior radiation exposure. None of these cases showed a BRAF mutation. RET/PTC1 (two out of seven) and RET/PTC3 (one out of seven), which have been shown in large PTC series to comprise together more than 90% of RET/PTC types, were found in <50% of the cases investigated. All seven samples expressed the RET tyrosine kinase domain but lacked its extracellular domain potentially suggesting the existence of rare types of RET/PTC rearrangement in the four remained cases of diffuse sclerosing variant of PTC. Regarding this subtype, our study confirmed the paradigm of a mutual exclusivity between RET/PTC and BRAF in PTC. Additionally, this rare variant of papillary thyroid carcinoma may represent a tumour type susceptible to RET-targeted therapies.

Lymphocyte and immature dendritic cell infiltrates in differentiated, poorly differentiated, and undifferentiated thyroid carcinoma

OBJECTIVE

Numerous studies indicate that papillary thyroid carcinomas (PTC) with lymphocytic infiltrates are associated with a less extensive disease at diagnosis and improved disease-free survival. The infiltration of lymphocytes and immature CD1a+ dendritic cells (DC) was characterized in papillary, poorly differentiated (PDC), and undifferentiated (UC) carcinomas to evaluate their association with immunological infiltrates.

DESIGN

A series of 527 consecutive cases of thyroid carcinoma treated by total thyroidectomy were investigated by histopathological and immunohistochemical methods. The inflammatory infiltrate was quantified and typed in intratumoral and peritumoral tissues as well as in the controlateral lobe.

MAIN OUTCOME

The intratumoral infiltrate was strongly reduced or absent in PDC and UC. Intense infiltrates were detected in the PTC tall cell variant. In all histotypes, the extent of the intratumoral and peritumoral infiltrates was comparable. Immature DC were detected in PTCs and markedly reduced in PDC and UC. CD1a+ DCs were detected in a small percentage of PDC and UC.

CONCLUSIONS

Though a relationship between the extent of lymphocyte/DC infiltrates and the prognosis of PTCs could not be demonstrated, tumors with poor prognosis (PDCs, UCs) were characterized by markedly reduced lymphocyte/DC infiltrates. The study appears to confirm the protective role of DC and infiltrating lymphocytes against thyroid tumors.