Diffuse sclerosing variant of papillary thyroid carcinoma—an update of its clinicopathological features and molecular biology

Management of aggressive variants of papillary thyroid cancer

PURPOSE OF REVIEW

The aim of this study was to provide a timely and relevant review of the latest findings and explore appropriate management of aggressive variants of papillary thyroid cancer (AVPTC).

RECENT FINDINGS

In general, AVPTCs tend to exhibit more invasive characteristics, a lack of responsiveness to radioiodine, increased occurrences of regional spreading, distant metastases and higher mortality rates. Meanwhile, each variant showcases unique clinical and molecular profiles.

SUMMARY

Given the elevated risk of recurrence postsurgery, a more aggressive strategy may be necessary when suspected preoperatively, particularly for those presenting with invasive features. Decision on the extent of surgical treatment and adjuvant therapy is individualized and made by experienced clinicians and multidisciplinary teams based on the clinical presentation, presence of aggressive features and molecular profile. Future studies on development of personalized medicine and molecular target therapy may offer tailored treatment options.

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.

Postoperative recurrence of diffuse sclerosing thyroid cancer in an adolescent patient: A case report

BACKGROUND

Papillary thyroid cancer is an inert malignant tumor with a good response to surgical treatment, low recurrence and metastasis rate, and good prognosis. Diffuse sclerosing thyroid cancer is an invasive subtype that is more common in young people, with a higher rate of lymph node metastasis and recurrence, and a relatively poor prognosis.

PATIENT CONCERNS

A 13-year-old girl underwent radical surgery for diffuse sclerosing thyroid cancer. Eight years later, due to a large number of lymph node metastases, she underwent another radical surgery on her neck lymph nodes.

METHODS

The patient thyroid ultrasound and neck enhanced CT indicated that the patient had multiple enlarged lymph nodes in the neck with irregular morphology and structure, and the possibility of metastatic lymph nodes was high. Subsequently, the patient underwent thyroid fine-needle aspiration and the results showed that cancer cells were detected in both cervical lymph nodes.

DIAGNOSIS

The patient was diagnosed with bilateral cervical lymph node metastases after thyroid surgery.

RESULTS

After the second surgery, the patient recovered well, and no residual or focal iodine uptake tissue was found on the enhanced CT examination.

CONCLUSION

As diffuse sclerosing thyroid cancer is prone to lymph node and recurrent metastases, once it is diagnosed, radical treatment should be actively performed. Postoperative adjuvant radiation therapy should be administered according to the patient condition and regular follow-ups should be conducted to monitor neck lymph node metastasis.

Occult Metastatic Papillary Thyroid Cancer in an Adolescent

Background/Objective

Occult papillary thyroid carcinoma (PTC) is PTC with metastasis but without identification of primary thyroid cancer on preoperative ultrasonography. Published reports on occult PTC in children are limited.

Case Report

We describe a 16-year-old female with occult PTC who initially presented with a painless left sided cystic neck mass. Diffuse sclerosing variant papillary thyroid cancer was found in the resected neck mass and thyroid ultrasound did not show any nodules or features of carcinoma. After total thyroidectomy, pathological examination of the thyroid revealed papillary thyroid microcarcinoma.

Discussion

We describe a rare case of occult diffuse sclerosing variant papillary thyroid cancer presenting as a cystic neck mass mimicking a second branchial cleft cyst in an adolescent patient. When metastatic PTC is found without evidence of nodule on thyroid imaging, occult PTC of the thyroid is the likely diagnosis.

Conclusion

Total thyroidectomy ± neck dissection followed by TSH suppression and radioactive iodine therapy remains the appropriate diagnostic and therapeutic interventions.

WHO 2022 updates on follicular cell and c-cell derived thyroid neoplasm

The latest edition of the WHO Classification of thyroid tumors was released in 2022 and incorporates novel concepts vital to patient management. Thyroid follicular nodular disease is a term used to collectively represent a wide variety of benign and non-neoplastic lesions, including both clonal and non-clonal proliferations that manifest clinically as multinodular goiter. Thyroid neoplasms develop from follicular cells and can be either benign, low-risk, or malignant. To avoid classifying all lesions under 1 cm in diameter as low-risk illnesses, the new classification method highlights the need for subtyping papillary thyroid cancer based on histomorphologic indicators rather than tumor size. Formerly known as the cribriform-morular variety of papillary thyroid carcinoma, this tumor is now more commonly referred to by its more accurate name, cribriform-morular thyroid carcinoma. Its histogenesis is unknown. Similar to the traditional definition of 'poorly differentiated thyroid carcinoma' according to the Turin criteria, the newly defined 'differentiated high-grade thyroid carcinoma' encompasses papillary thyroid cancer, follicular thyroid carcinomas, and oncocytic carcinomas with high-grade characteristics linked to worse prognosis. The squamous cell subtype of anaplastic thyroid cancer has also recently been characterized as a distinct morphologic pattern. In this article, we will discuss the latest revision to the World Health Organization's classification system for thyroid cancer.

A Detailed Histologic and Molecular Assessment of the Diffuse Sclerosing Variant of Papillary Thyroid Carcinoma

Diffuse sclerosing variant papillary thyroid carcinoma (DS-PTC) is characterized clinically by a predilection for children and young adults, bulky neck nodes, and pulmonary metastases. Previous studies have suggested infrequent BRAFV600E mutation but common RET gene rearrangements. Using strict criteria, we studied 43 DS-PTCs (1.9% of unselected PTCs in our unit). Seventy-nine percent harbored pathogenic gene rearrangements involving RET, NTRK3, NTRK1, ALK, or BRAF; with the remainder driven by BRAFV600E mutations. All 10 pediatric cases were all gene rearranged (P = .02). Compared with BRAFV600E-mutated tumors, gene rearrangement was characterized by psammoma bodies involving the entire lobe (P = .038), follicular predominant or mixed follicular architecture (P = .003), pulmonary metastases (24% vs none, P = .04), and absent classical, so-called "BRAF-like" atypia (P = .014). There was no correlation between the presence of gene rearrangement and recurrence-free survival. Features associated with persistent/recurrent disease included pediatric population (P = .030), gene-rearranged tumors (P = .020), microscopic extrathyroidal extension (P = .009), metastases at presentation (P = .007), and stage II disease (P = .015). We conclude that DS-PTC represents 1.9% of papillary thyroid carcinomas and that actionable gene rearrangements are extremely common in DS-PTC. DS-PTC can be divided into 2 distinct molecular subtypes and all BRAFV600E-negative tumors (1.5% of papillary thyroid carcinomas) are driven by potentially actionable oncogenic fusions.

Hashimoto's Thyroiditis and the Risk of Papillary Thyroid Cancer in Children

The association between Hashimoto's thyroiditis (HT) and pediatric thyroid cancer is controversial. Most studies examining this connection have been based on adults, and larger studies in children are lacking. We performed a retrospective study of all sequential pediatric patients who underwent a thyroidectomy for a neoplasm at our institution over a twenty-year period in order to explore the link between HT and pediatric thyroid cancer. A total of 153 patients, median age 16.5 (interquartile range [IQR] 14.2-18.3) years, underwent thyroid surgery for a neoplasm. Patients were mainly female (80%) and White (84%). Median follow-up was 58.6 (IQR 20.7-105.4) months. Thirty-five (23%) patients had HT. Patients who underwent thyroid surgery and had HT were more likely to harbor a malignant neoplasm (p = 0.05); specifically, papillary thyroid carcinoma (PTC, p = 0.02). There was a difference in the distribution of HT among the subtypes of PTC (p = 0.03). Despite this, there was no difference in terms of survival between patients with/without HT. In conclusion, children with a thyroid malignancy, specifically, PTC, are more likely to have HT. The association between HT and pediatric PTC appears to be subtype-specific but does not seem to affect patient survival.

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.

Molecular Genetics of Diffuse Sclerosing Papillary Thyroid Cancer

CONTEXT

Diffuse sclerosing papillary thyroid cancer (DSPTC) is rare, with limited data on its molecular genetics.

OBJECTIVE

We studied the molecular genetics of a cohort of DSPTC.

METHODS

DNA was isolated from paraffin blocks of 22 patients with DSPTC (15 females, 7 males, median age 18 years, range 8-81). We performed polymerase chain reaction-based Sanger sequencing and a next-generation sequencing (NGS) gene panel to characterize the genomic landscape of these tumors. We classified genetic alterations to definitely or probably pathogenic. Definitely pathogenic are genetic alterations that are well known to be associated with PTC (e.g., BRAFV600E). Probably pathogenic are other alterations in genes that were reported in The Cancer Genome Atlas or the poorly differentiated and anaplastic thyroid cancer datasets.

RESULTS

Three tumors were tested only by Sanger sequencing and were negative for BRAFV600E, HRAS, KRAS, NRAS, TERT promoter, PTEN, and PIK3CA mutations. The other 19 tumors tested by NGS showed definitely pathogenic alterations in 10 patients (52.6%): 2/19 (10.5%) BRAFV600E, 5/19 (26.3%) CCDC6-RET (RET/PTC1), 1/19 (5.3%) NCOA4-RET (RET/PTC3), 1/19 (5.3%) STRN-ALK fusion, and 2/19 (10.6%) TP53 mutations. Probably pathogenic alterations occurred in 13/19 tumors (68.4%) and included variants in POLE (31.6%), CDKN2A (26%), NF1 (21%), BRCA2 (15.8%), SETD2 (5.3%), ATM (5.3%), FLT3 (5.3%), and ROS1 (5.3%). In 1 patient, the gene panel showed no alterations. No mutations were found in the RAS, PTEN, PIK3CA, or TERT promoter in all patients. There was no clear genotype/phenotype correlation.

CONCLUSION

In DSPTC, fusion genes are common, BRAFV600E is rare, and other usual point mutations are absent. Pathogenic and likely pathogenic variants in POLE, NF1, CDKN2A, BRCA2, TP53, SETD2, ATM, FLT3, and ROS1 occur in about two-thirds of DTPTC.

Diffuse Sclerosing Papillary Thyroid Carcinoma: Clinicopathological Characteristics and Prognostic Implications Compared with Classic and Tall Cell Papillary Thyroid Cancer

BACKGROUND

The clinical behaviour and oncologic outcome of diffuse sclerosing papillary thyroid carcinoma (DS-PTC) is poorly understood. The objectives of this study were to compare the clinicopathological characteristics and oncological outcomes of DS-PTC to classic PTC (cPTC) and tall cell PTC (TC-PTC).

METHODS

After institutional review board approval, 86 DS-PTC, 2,080 cPTC, and 701 TC-PTC patients treated at MSKCC between 1986 and 2021 were identified. Clinicopathological characteristics were compared by using chi-square test. Kaplan-Meier and log rank were used to compare recurrence-free survival (RFS), disease-specific survival (DSS), and overall survival (OS). DS-PTC patients were propensity matched to cPTC and TC-PTC patients for further comparison.

RESULTS

DS-PTC patients were younger with more advanced disease than cPTC and TC-PTC (p < 0.05). Lymphovascular invasion (LVI), extranodal extension, and positive margins were more common in DS-PTC (p < 0.02). Propensity matching confirmed more aggressive histopathological features in DS-PTC. The median number of metastatic lymph nodes was significantly greater and DS-PTC metastases were RAI avid. DS-PTC 5-year RFS was 50.4% compared with 92.4% in cPTC and 88.4% in TC-PTC (p < 0.001). Multivariate analysis confirmed DS-PTC as an independent prognostic factor of recurrence. Ten-year DSS for DS-PTC was 100% compared with 97.1% in cPTC and 91.1% in TC-PTC. Differentiated high-grade, thyroid carcinoma DS had more advanced T-stage and worse 5-year RFS than DS-PTC.

CONCLUSIONS

DS-PTC presents with more advanced clinicopathological features than cPTC and TC-PTC. Large-volume nodal metastases and LVI are characteristic features. Almost half of patients develop recurrence despite aggressive initial management. Despite this, with successful salvage surgery DSS is excellent.

Clinicopathological and Genetic Characteristics of Patients of Different Ages with Diffuse Sclerosing Variant Papillary Thyroid Carcinoma

Diffuse sclerosing variant papillary thyroid carcinoma (DSVPTC) is commonly observed in young patients, with a median age at diagnosis in the third decade of life. Further, the risk of recurrence is higher for DSVPTC than for classical PTC. Therefore, this study aimed to describe the clinicopathological and genetic characteristics of patients of different ages with DSVPTC. We retrospectively reviewed 397 patients who underwent thyroidectomy for DSVPTC at Gangnam Severance Hospital, Yonsei University, from January 2005 to December 2017. The mean age at diagnosis was 36.7 ± 11.6 years, with most patients (163, 41.1%) aged 31-40 years. DSVPTC was predominant in women (276, 69.5%). We observed recurrence in 46 (11.6%) patients, with regional nodal recurrence being the most common type of recurrence (32 patients, 69.6%). The mean tumour size was larger in younger patients than in older patients. DSVPTC was more aggressive in paediatric patients with a larger-sized tumour, more common multiplicity, and lateral neck metastasis. Through random sampling, we selected 41 patients by age group and examined the mutations in 119 genes using next-generation sequencing. BRAF, KRAS, and TERT displayed relatively higher mutation rates than other genes. DSVPTC displays different clinical, pathological, and molecular profiles than classical PTC. The BRAF, KRAS, and TERT mutations are the most important, with age-specific differences.

The Presence of Typical "BRAFV600E-Like" Atypia in Papillary Thyroid Carcinoma is Highly Specific for the Presence of the BRAFV600E Mutation

Papillary thyroid carcinomas (PTCs) are driven by a variety of molecular abnormalities including BRAF, RAS, ALK, RET, and NTRK alterations. PTCs driven by the BRAFV600E mutation, or tumours which demonstrate a similar gene expression profile to PTCs driven by this mutation, have been reported to demonstrate specific morphological features sometimes termed "BRAFV600E-like" atypia. BRAFV600E-like atypia is characterised by a well-developed papillary architecture, infiltrative growth, marked nuclear clearing, prominent intranuclear pseudoinclusions, abundant eosinophilic cytoplasm, and scattered psammoma bodies. We sought to investigate the sensitivity and specificity of these morphological features for the presence of BRAFV600E mutation in PTCs as determined by mutation specific immunohistochemistry. An unselected cohort of 495 PTCs was reviewed by a single pathologist and categorised into three groups: typical BRAFV600E-like atypia (145 cases, 29%), possible BRAFV600E-like atypia (166 cases, 33%) and little/no BRAFV600E-like atypia (184 cases, 37%). The specificity and sensitivity of typical BRAFV600E-like atypia for the BRAFV600E mutation was 97.2% and 44.3%, respectively. When typical and possible BRAFV600E-like atypia were analysed together, the specificity was 70.6% and the sensitivity was 81.7%. In the morphologically little/no BRAFV600E-like atypia group, 58 cases (31.5%) had a BRAFV600E mutation. We conclude that typical BRAFV600E-like atypia is highly specific for the presence of the BRAFV600E mutation; however, the absence of BRAFV600E-like atypia does not exclude this mutation.

[Modern aspects influencing the management of patients with papillary thyroid cancer]

Thyroid cancer (TC) is the most common malignant tumor of the endocrine glands and accounts to 3% of the total structure of oncological morbidity. Papillary thyroid cancer (PTC) is the most common histological variant of thyroid malignancies. It accounts for about 85% of all cases of thyroid cancer. Despite good postoperative results and excellent survival compared to many other malignancies, tumor metastases to the paratracheal lymph nodes are quite common. This review of the literature considers the current personalized approach to patients with papillary thyroid cancer and current aspects influencing the management of patients with PTC.

DICER1 Mutations Occur in More Than One-Third of Follicular-Patterned Pediatric Papillary Thyroid Carcinomas and Correlate with a Low-Risk Disease and Female Gender Predilection

Some pediatric papillary thyroid carcinoma (PPTC) cohorts have suggested a preliminary correlation with respect to DICER1 mutation status and histomorphology in both benign and malignant follicular cell-derived nodules; however, the data regarding correlates of DICER1-related sporadic PPTCs subtyped based on the 2022 WHO classification criteria are largely unavailable. The current study investigated the status of hotspot DICER1 mutations with clinical, histological and outcome features in a series of 56 patients with PPTCs with no clinical or family history of DICER1-related syndromic manifestation. Fifteen (27%) PPTCs harbored BRAF p.V600E. Eight (14%) cases of PPTCs harbored DICER1 mutations with no associated BRAF p.V600E. DICER1 mutations were identified in exons 26 and 27. A novel D1810del (c.5428_5430delGAT) mutation was also detected. We also confirmed the absence of hotspot DICER1 mutations in the matched non-tumor tissue DNA in all 8 DICER1-related PPTCs. The mean age of DICER1-harboring PPTCs was 15.1 (range: 9-18) years whereas the rest of this cohort had a mean age of 14.8 (range 6-18) years. With the exception of one PPTC, all DICER1-related PPTCs were seen in females (female-to-male ratio: 7). The female to male ratio was 3.8 in 48 DICER1-wild type PPTCs. In terms of histological correlates, 5 of 8 (63%) DICER1-mutant PPTCs were invasive encapsulated follicular variant papillary thyroid carcinomas (FVPTCs) including 4 minimally invasive FVPTCs and 1 encapsulated angioinvasive FVPTC, whereas the remaining 3 PPTCs were infiltrative classic papillary thyroid carcinomas (p < 0.05). The incidence of DICER1 mutations was 19.5% in BRAF p.V600E-wild type PPTCs. Sixty-three percent of DICER1 hotspot mutations occurred in invasive encapsulated FVPTCs, and this figure represents 38% of invasive encapsulated FVPTCs. Only one (12%) patient with DICER1-related disease showed a single lymph node with micro-metastasis. Unlike DICER1-wild type patients, no distant metastasis is identified in patients with DICER1-related PPTCs. The current series expands on the surgical epidemiology of somatic DICER1-related PPTCs by correlating the mutation status with the clinicopathological variables. Our findings underscore that female gender predilection and enrichment in low-risk follicular-patterned PTCs are characteristics of DICER1-related PPTCs.

Aggressive variants of follicular cell-derived thyroid carcinoma: an overview

PURPOSE

The incidence of thyroid carcinoma has increased globally in the past years. Papillary thyroid carcinoma (PTC) is the most frequent neoplasm of the thyroid gland comprehending the 90% of the thyroid carcinoma and has an indolent clinical behaviour. However, some variants of follicular cell-derived thyroid carcinoma, including variants of classic of PTC, have been identified that show a more aggressive biological behaviour. An accurate diagnosis of these entities is crucial for planning a more aggressive treatment and improving patients' prognosis of patients. The aim of this review is to present the main clinical, histological, and molecular features of aggressive variants of follicular cell-derived thyroid carcinoma, and to provide useful histological parameters for determining the most suitable therapeutic strategy for patients affected by these forms.

RESULTS

Variants of classic PTC such as the diffuse sclerosing variant (DSV), the tall cell variant (TCV), the columnar cell variant (CCV), the solid/trabecular variant (STV) and the hobnail variant (HV), and other variants of follicular cell-derived thyroid carcinoma, such as poorly differentiated thyroid carcinoma (PDTC), and anaplastic thyroid carcinoma (ATC), are associated with aggressive behaviour.

CONCLUSIONS

The correct identification and diagnosis of aggressive variants of follicular cell-derived thyroid carcinoma is important, as they allow the clinician to adopt the most refined therapeutic strategies in order to the survival of the patients.

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.

Papillary Thyroid Carcinoma: Current Position in Epidemiology, Genomics, and Classification

Papillary thyroid carcinoma is the most common type of thyroid malignancy both in adults and pediatric population. Since the 1980s, there are changes in criteria in labelling thyroid lesions as "papillary thyroid carcinomas." Radiation exposure is a well-established risk factor for papillary thyroid carcinoma. Other environmental risk factors include dietary iodine, obesity, hormones, and environmental pollutants. Papillary thyroid carcinomas could occur in familial settings, and 5% of these familial cases have well-studied driver germline mutations. In sporadic papillary thyroid carcinoma, BRAF mutation is common and is associated with clinicopathologic and prognostic markers. The mutation could aid in the clinical diagnosis of papillary thyroid carcinoma. Globally, thyroid cancer is among the top ten commonest cancer in females. In both adult and pediatric populations, there are variations of prevalence of thyroid cancer and rising incidence rates of thyroid cancer worldwide. The increase of thyroid cancer incidence was almost entirely due to the increase of papillary thyroid carcinoma. The reasons behind the increase are complex, multifactorial, and incompletely understood. The most obvious reasons are increased use of diagnostic entities, change in classification of thyroid neoplasms, as well as factors such as obesity, environmental risk factors, and radiation. The prognosis of the patients with papillary thyroid carcinoma is generally good after treatment. Nevertheless, cancer recurrence and comorbidity of second primary cancer may occur, and it is important to have awareness of the clinical, pathological, and molecular parameters of papillary thyroid carcinoma.

Predictive Factors Indicative of Hemithyroidectomy and Close Follow-Up versus Bilateral Total Thyroidectomy for Aggressive Variants of Papillary Thyroid Cancer

Simple Summary

This study evaluated the need for additional surgical treatment in patients diagnosed with aggressive variants of papillary thyroid cancer after lobectomy. With the increase in the frequency of early diagnosis, the detection of papillary thyroid cancer pathologically belonging to the aggressive variant is also increasing. Therefore, there is growing concern regarding the aggressive treatment of encapsulated aggressive variants of papillary thyroid cancer without invasive features. We suggest that close follow-up can be performed without any additional surgical treatment in patients with low-risk aggressive variants of papillary thyroid cancer incidentally detected after hemithyroidectomy. The patients should be provided sufficient consultation with clinicians.

Abstract

The diagnostic and treatment rates of early thyroid cancer have been increasing, including those of aggressive variants of papillary thyroid cancer (AVPTC). This study aimed to analyze the need for completion total thyroidectomy after lobectomy for clinically low-to-intermediate-risk AVPTC. Overall, 249 patients who underwent hemithyroidectomy (HT, n = 46) or bilateral total thyroidectomy (BTT, n = 203) for AVPTC between November 2005 and December 2019 at our single institution were examined. The average follow-up period was 14.9 years, with a recurrence rate of 4.3% and 10.8% in the HT and BTT groups, respectively. Multivariate Cox analysis revealed that palpable tumor on the neck during evaluation (HR, 2.7; 95% CI, 1.1–6.4; p = 0.025), clinical N1b (HR, 8.3; 95% CI, 1.1–63.4; p = 0.041), tumor size (cm) (HR, 1.3; 95% CI, 1.0–1.7; p = 0.036), gross extrathyroidal extension (HR, 3.1; 95% CI, 1.4–7.0; p = 0.007), and pathologic T3b (HR, 3.4; 95% CI, 1.0–11.4; p = 0.045) or T4a (HR, 6.0; 95% CI, 1.9–18.8; p = 0.002) were associated with an increased risk of recurrence. Incidentalomas identified during diagnosis had a significantly lower risk of recurrence (HR, 0.4; 95% CI, 0.2–0.9; p = 0.033). Close follow-up may be performed without completion total thyroidectomy for AVPTC found incidentally after HT.

Risk and Prognostic Factors for BRAFV600E Mutations in Papillary Thyroid Carcinoma

Background

Over the past ten years, the incidence rate of papillary thyroid carcinoma (PTC) worldwide has been increasing rapidly year by year, with the incidence rate increasing 6% annually. PTC has become the malignant tumor with the highest growth rate in the world that fourteen PTC-related mutant genes have been identified. Whether the BRAF^V600E mutation related to more aggressive clinicopathologic features and worse outcome in PTC remains variable and controversial. We aim to investigate the risk factors that may predict the BRAF^V600E mutation potential of these lesions and new prevention strategies in PTC patients.

Methods

A total of 9,908 papillary thyroid carcinoma patients with average 74.6% BRAF^V600E mutations were analyzed (RevMan 5.3 software) in this study. The PubMed, Embase, and ISI Web of Science databases were systematically searched for works published through December 15, 2021.

Results

The following variables were associated with an increased risk of BRAF^V600E mutation in PTC patients: age ≥ 45 years (OR = 1.39, 95%CI = 1.21–1.60, p < 0.00001), male gender (OR = 1.13, 95%CI = 0.99–1.28, p = 0.06), multifocality (OR = 1.22, 95%CI = 1.07–1.40, p = 0.004), lymph node metastasis (OR = 1.33, 95%CI = 0.79–2.23, p = 0.28), extrathyroidal extension + (OR = 1.61, 95%CI = 1.06–2.44, p = 0.03), vascular invasion + (OR = 2.04, 95%CI = 1.32–3.15, p = 0.001), and tumor node metastasis stage (OR = 1.61, 95%CI = 1.38–1.88, p < 0.00001). In addition, tumor size (>1 cm) (OR = 0.51, 95%CI = 0.32–0.81, p = 0.005) and distant metastasis (OR = 0.69, 95%CI = 0.22–2.21, p = 0.54) had no association or risk with BRAF^V600E mutation in PTC patients.

Conclusion

Our systematic review identified the following significant risk factors of BRAF^V600E mutation in PTC patients: age (≥45 years), gender (male), multifocality, lymph node metastasis, vascular invasion, extrathyroidal extension, and advanced tumor node metastasis stage (stages III and IV). Tumor size (>1 cm) and distant metastasis do not appear to be correlated with BRAF^V600E mutation in PTC patients.

Overview of the 2022 WHO Classification of Thyroid Neoplasms

This review summarizes the changes in the 5th edition of the WHO Classification of Endocrine and Neuroendocrine Tumors that relate to the thyroid gland. The new classification has divided thyroid tumors into several new categories that allow for a clearer understanding of the cell of origin, pathologic features (cytopathology and histopathology), molecular classification, and biological behavior. Follicular cell-derived tumors constitute the majority of thyroid neoplasms. In this new classification, they are divided into benign, low-risk, and malignant neoplasms. Benign tumors include not only follicular adenoma but also variants of adenoma that are of diagnostic and clinical significance, including the ones with papillary architecture, which are often hyperfunctional and oncocytic adenomas. For the first time, there is a detailed account of the multifocal hyperplastic/neoplastic lesions that commonly occur in the clinical setting of multinodular goiter; the term thyroid follicular nodular disease (FND) achieved consensus as the best to describe this enigmatic entity. Low-risk follicular cell-derived neoplasms include non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP), thyroid tumors of uncertain malignant potential, and hyalinizing trabecular tumor. Malignant follicular cell-derived neoplasms are stratified based on molecular profiles and aggressiveness. Papillary thyroid carcinomas (PTCs), with many morphological subtypes, represent the BRAF-like malignancies, whereas invasive encapsulated follicular variant PTC and follicular thyroid carcinoma represent the RAS-like malignancies. This new classification requires detailed subtyping of papillary microcarcinomas similar to their counterparts that exceed 1.0 cm and recommends not designating them as a subtype of PTC. The criteria of the tall cell subtype of PTC have been revisited. Cribriform-morular thyroid carcinoma is no longer classified as a subtype of PTC. The term "Hürthle cell" is discouraged, since it is a misnomer. Oncocytic carcinoma is discussed as a distinct entity with the clear recognition that it refers to oncocytic follicular cell-derived neoplasms (composed of > 75% oncocytic cells) that lack characteristic nuclear features of PTC (those would be oncocytic PTCs) and high-grade features (necrosis and ≥ 5 mitoses per 2 mm²). High-grade follicular cell-derived malignancies now include both the traditional poorly differentiated carcinoma as well as high-grade differentiated thyroid carcinomas, since both are characterized by increased mitotic activity and tumor necrosis without anaplastic histology and clinically behave in a similar manner. Anaplastic thyroid carcinoma remains the most undifferentiated form; squamous cell carcinoma of the thyroid is now considered as a subtype of anaplastic carcinoma. Medullary thyroid carcinomas derived from thyroid C cells retain their distinct section, and there is a separate section for mixed tumors composed of both C cells and any follicular cell-derived malignancy. A grading system for medullary thyroid carcinomas is also introduced based on mitotic count, tumor necrosis, and Ki67 labeling index. A number of unusual neoplasms that occur in the thyroid have been placed into new sections based on their cytogenesis. Mucoepidermoid carcinoma and secretory carcinoma of the salivary gland type are now included in one section classified as "salivary gland-type carcinomas of the thyroid." Thymomas, thymic carcinomas and spindle epithelial tumor with thymus-like elements are classified as "thymic tumors within the thyroid." There remain several tumors whose cell lineage is unclear, and they are listed as such; these include sclerosing mucoepidermoid carcinoma with eosinophilia and cribriform-morular thyroid carcinoma. Another important addition is thyroblastoma, an unusual embryonal tumor associated with DICER1 mutations. As in all the WHO books in the 5th edition, mesenchymal and stromal tumors, hematolymphoid neoplasms, germ cell tumors, and metastatic malignancies are discussed separately. The current classification also emphasizes the value of biomarkers that may aid diagnosis and provide prognostic information.

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.

Concepts of Pathological Staging and Prognosis in Papillary Thyroid Carcinoma

American Joint Committee on Cancer (AJCC)/Union for International Cancer Control (AJCC/UICC) staging and American Thyroid Association (ATA) risk predication system are the best predicators of mortality and cancer recurrence, respectively, in patients with differentiated thyroid carcinoma, including papillary thyroid carcinoma. In ATA risk stratification of differentiated thyroid carcinomas, clinical features, nodal features, and pathological features are assessed. Many of the features are also assessed in pathological staging. The prognostic stage grouping of papillary thyroid carcinoma in AJCC/UICC depends on the age of the patients as well as the standard parameters-extent of tumor (T), lymph node status (N), and presence of distant metastasis (M). Major changes noted in the current pathological staging protocol include the cut-off age from 45-year to 55-year in grouping of patients, use of gross invasion of strap muscles instead of minimal microscopic extrathyroidal extensions as T3b and downstage of many prognostic groups such as those with lymph node metastases (without distant metastases) from Stage III to Stage II. The staging protocol have moved many patients with papillary thyroid carcinoma into good prognostic groups for better predication of patients' survival rates and to avoid unnecessary treatment. This new approach has been verified by different groups globally, although modifications could be expected in the future for better prognostic assessment in patients with papillary thyroid carcinoma.

Histopathological Assessment for Papillary Thyroid Carcinoma

Histologic assessments of papillary thyroid carcinoma are crucial for management of patients with the cancer as well as research on the cancer as papillary thyroid carcinoma has different histologic subtypes and many parameters which are essential in predicting the biological aggressiveness of the cancer. The histologic assessments should be guided by universally adopted protocols including World Health Organization (WHO) classification of endocrine tumors, International Collaboration on Cancer Reporting (ICCR) dataset, American Thyroid Association initial risk stratification for differentiated thyroid carcinomas and TNM stage groupings. The essential steps in histologic assessment involve the identification of characteristic features of papillary thyroid carcinoma, correct histologic subtyping, noting the number of carcinomas, measuring the size of the carcinoma, documenting the different aggressive histological parameters (mitotic activity, presence of tumor encapsulation/circumscription, lymphatic vessel invasion, blood vessel invasion, necrosis, extrathyroidal extension), resection margin status, associated pathology, presence of parathyroid gland, lymph node and distant metastases as well as synthesis of pathological stage based on the various clinical, macroscopic, and histological features.

BRAF Mutations in Papillary Thyroid Carcinoma: A Genomic Approach Using Probe-Based DNA Capture for Next-Generation Sequencing

The BRAF V600E mutation in papillary thyroid carcinoma is the major mutation in classical subtype of papillary thyroid carcinoma and other cancers. It is the most studied predictor of clinical and pathological characteristics as well as molecular targets for cancer therapy. On the other hand, there is potential for many more forms of activating mutation in BRAF that are not detectable by simple assays to detect V600E, or even simple polymerase chain reaction (PCR)-based sequencing for full-length BRAF. Such activating mutations could arise from larger-scale rearrangements which may apparently leave no sequence change to BRAF while causing increased expression or activation by unusual means, such as gene fusion. Detection of these kinds of changes can take place using a variety of methods, though capture-based sequencing can identify the existence of such forms of mutant BRAF without needing foreknowledge of the loci involved in these kinds of mutation. In this chapter, we detail a method for capture of specific DNA sequences and their amplification to prepare for massively parallel sequencing.

Squamous Differentiation in the Thyroid: Metaplasia, Neoplasia, or Bystander?

Background. Squamous differentiation within the thyroid is seen in a variety of settings. Squamous epithelium is non-native to the thyroid, and its debated origins span reactive metaplasia and developmental/embryologic remnants. Despite a lack of clarity as to its evolution, squamous epithelium may be associated with both neoplastic and non-neoplastic processes. Methods. Thyroid pathology reports spanning a 30-year period were reviewed for terms indicating squamous features. Associated diagnostic and clinical information was collated. Results. Four hundred and twenty seven of 17,452 (2.4%) thyroid surgical pathology cases during this period utilized terminology indicating squamous differentiation including 243 malignant (58%) and 178 benign (42%) diagnoses. There were 111 (26%) primary thyroid malignancies with squamous differentiation, 116 (28%) malignancies of non-thyroid origin including local extension from nearby cancers, and 16 (4%) malignancies of uncertain primary. Most benign lesions were non-neoplastic (84%). The minor subset representing benign neoplasia was interpreted as secondary reactive changes. Conclusion. While squamous differentiation is seen routinely in the thyroid, it is most commonly reported in malignancy. For primary thyroid malignancies reported to demonstrate a squamous component, biologically aggressive tumors were overrepresented. Available evidence suggests that multiple pathways may contribute to the presence of squamous epithelium in the thyroid including metaplasia of mature follicular cells, development from established embryonic remnants, or inception in putative, incompletely characterized stem-like cells. Our retrospective review presents an institutional landscape from which further investigation into the frequency and unique histologic and molecular context of intrathyroidal squamous differentiation as a driver or terminal event in thyroid pathophysiology.

Clinical Outcomes of Diffuse Sclerosing Variant Papillary Thyroid Carcinoma in Pediatric Patients

OBJECTIVES/HYPOTHESIS

The diffuse sclerosing variant of papillary thyroid carcinoma (DSV) may be more aggressive than conventional well-differentiated non-DSV related papillary thyroid carcinomas (N-PTC).

STUDY DESIGN

Retrospective chart review.

METHODS

Retrospective review of clinical outcomes for patients 21 years of age or younger who underwent initial surgery for PTC at a single institution from January 1, 2005 to April 1, 2020. Genomic analysis was performed using targeted next-generation sequencing. Data were analyzed using Fischer's exact test and Kaplan-Meier curve log-rank test.

RESULTS

Our cohort consisted of 72 patients, nine with DSV and 63 with N-PTC. Age at diagnosis was comparable (15.4 vs. 16.2 years, respectively, P = .46). DSV were more likely to be in the high-risk American Thyroid Academy pediatric risk group (100% vs. 41.3%, P = .004), to present with regional cervical lymph node metastases (100% vs. 60.3%, P = .036), and to present with distant metastases (67% vs. 22%, P = .005). No mortality seen in either group over 27.5 (interquartile range 14.8, 46.00) months average follow-up. Throughout the follow-up period, DSV were more likely to experience progression than N-PTC (hazard ratio = 5.7 [95% confidence interval 1.7-20.0; P = .0056]). In a subset of 19 patients with aggressive disease who had molecular testing as part of clinical care we detected RET fusions in nearly all DSV compared to a minority of N-PTC (83% vs. 15.4%, P = .0095).

CONCLUSIONS

Pediatric patients with DSV have more advanced disease at diagnosis and are more likely to experience progression of disease compared to patients with N-PTC. The prevalence of RET fusions in our cohort recapitulates the frequency of this alteration described in prior studies.

LEVEL OF EVIDENCE

4 Laryngoscope, 2021.

Predictive Impact of Metastatic Lymph Node Burden on Distant Metastasis Across Papillary Thyroid Cancer Variants

Background: While numerous factors determine prognosis in papillary thyroid carcinoma (PTC), distant metastasis (M1) represents one of the most dire. Escalating nodal burden and aggressive histology may contribute to higher metastatic risk, but this relationship is poorly defined and challenging to anticipate. We evaluate the predictive impact of these histological features on predicting distant metastases at initial presentation. Methods: Univariate and multivariable logistic regression models of conventional and aggressive thyroid cancer variants (well-differentiated papillary thyroid carcinoma [WDPTC], diffuse sclerosing variant [DSV], tall cell variant [TCV], poorly differentiated thyroid cancer [PDTC], and anaplastic thyroid carcinoma [ATC]) identified via U.S. cancer registry data were constructed to determine associations between M1 status and quantitative nodal burden. Associations between metastatic lymph node (LN) number and M1 disease were modeled using univariate and multivariable logistic regression with interaction terms, as well as a linear continuous probability model. Results: Overall, M1 prevalence at disease presentation was 3.6% (n = 1717). When stratified by subtype, M1 prevalence varied significantly by histology (WDPTC [1.0%], DSV [2.3%], TCV [4.1%], PDTC [17.4%], ATC [38.4%] [p < 0.001]). For WDPTC, M1 prevalence escalated with metastatic LN number (0 LN+ [0.5%], 1-5 LN+ [2.0%], 6-10 LN+ [3.4%], >10 LN+ [5.5%] [p < 0.001]) and LN ratio (p < 0.001). A statistically significant interaction was observed between histology and increasing nodal burden for M1 risk. On multivariable analysis, each successive metastatic LN conferred increased M1 risk for WDPTC (odds ratio [OR] 1.06 [1.05-1.08], p < 0.001) and TCVs (OR 1.04 [1.02-1.07], p < 0.001). In contrast, other aggressive variants had a higher baseline M1 risk, but this did not vary based on the number of positive LN (DSV, OR 1.02 [0.95-1.10], p = 0.52; PDTC, OR 1.00 [0.98-1.02], p = 0.66; ATC, 1.00 [0.98-1.02], p = 0.97). Conclusions: Progressive nodal burden independently escalates the risk of distant metastasis in WDPTC and TCVs of PTC. Conversely, aggressive variants such as PDTC and ATC have substantial M1 risk at baseline and appear to be minimally affected by metastatic nodal burden. Consideration of these factors after surgery may help tailor clinical decision-making for treatment and surveillance. Further studies are warranted to calibrate the ideal management approach for these higher risk patient groups.

Diffuse intrathyroidal dissemination of papillary thyroid carcinoma with no stromal fibrosis at presentation: A pattern of aggressive differentiated thyroid carcinoma

BACKGROUND

Multifocal Papillary thyroid carcinoma (PTC) is a very common condition. In certain cases, it is possible to find tens to hundreds of foci with a diffuse intrathyroidal spread in the whole thyroid with no stromal fibrosis. Herein, PTC with such features was nominated as diffuse disseminate variant (DDV) PTC. The aim of the present study was to investigate the histopathological characteristics, molecular features, and biological behavior of DDV and compare the characteristics of DDV to diffuse sclerosing variant (DSV) PTC.

MATERIALS AND METHODS

Thirty-four DDV and 23 DSV cases were identified from consecutive surgical specimens diagnosed with PTC between 2014 and 2019. Targeted next-generation sequencing (NGS) was applied to investigate the mutation spectrum of DDV and DSV.

RESULTS

DDV was commonly diagnosed in young patients and exhibited high rates of LNM (100 %), ETE (61.8 %), and LVI (44.1 %); however, they did not differ from DSV (P >  0.05). Male patients were more frequently diagnosed with DDV than with DSV (P <  0.001). The size of the largest tumor was significantly greater in DDV than in DSV patients (P =  0.008). In addition, BRAF^V600E mutation was significantly higher in the DDV than in the DSV group (P <  0.001). The RET/PTC rearrangement was more frequent in DSV than in DDV patients; however, the difference was not statistically significant (P =  0.106). Moreover, DDV had a higher rate of recurrence compared to DSV treated with the same protocol (total thyroidectomy followed by radioactive iodine (RAI) treatment) (47.1 % and 8.7 %, P =  0.002).

CONCLUSIONS

DDV should be regarded as a novel aggressive variant of PTC with distinct clinicopathological characteristics, aggressive biological behaviors, and a high recurrence.

CircRNA_104565 Promoted Cell Proliferation in Papillary Thyroid Carcinoma by Sponging miR-134

BACKGROUND

Thyroid cancer is one of the most common cancers with rising incidence worldwide, and papillary thyroid carcinoma (PTC) accounts for 80-85% of thyroid malignancy. Although it has been reported that many genes relate to the carcinogenesis of PTC, the molecular mechanisms remain mostly unclear.

METHODS

QRT-PCR assay was performed to detect circRNA_104565, miR-134 and ELF2 expression. CCK8 assay was exercised to examine cell proliferation. Western blot was used to detect ELF2 expression.

RESULTS

We found that circRNA_104565 was highly expressed in PTC tissue and cell and promoted cell proliferation in vitro and in vivo. In addition, circRNA_104565 promoted cell proliferation in PTC by regulating the miR-134/ELF2 axis.

CONCLUSION

Hence, revealing the function of circRNA_104565 in PTC is important for understanding the molecular mechanism of carcinogenesis and providing new biomarkers or therapeutic targets for PTC.

Consensus statement by the American Association of Clinical Endocrinology (AACE) and the American Head and Neck Society Endocrine Surgery Section (AHNS-ES) on Pediatric Benign and Malignant Thyroid Surgery

OBJECTIVES

To provide a clinical disease state review of recent relevant literature and to generate expert consensus statements regarding the breadth of pediatric thyroid cancer diagnosis and care, with an emphasis on thyroid surgery. To generate expert statements to educate pediatric practitioners on the state-of-the-art practices and the value of surgical experience in the management of this unusual and challenging disease in children.

METHODS

A literature search was conducted and statements were constructed and subjected to a modified Delphi process to measure the consensus of the expert author panel. The wording of statements, voting tabulation, and statistical analysis were overseen by a Delphi expert (J.J.S.).

RESULTS

Twenty-five consensus statements were created and subjected to a modified Delphi analysis to measure the strength of consensus of the expert author panel. All statements reached a level of consensus, and the majority of statements reached the highest level of consensus.

CONCLUSION

Pediatric thyroid cancer has many unique nuances, such as bulky cervical adenopathy on presentation, an increased incidence of diffuse sclerosing variant, and a longer potential lifespan to endure potential complications from treatment. Complications can be a burden to parents and patients alike. We suggest that optimal outcomes and decreased morbidity will come from the use of advanced imaging, diagnostic testing, and neural monitoring of patients treated at high-volume centers by high-volume surgeons.

Consensus Statement by the American Association of Clinical Endocrinology (AACE) and the American Head and Neck Society Endocrine Surgery Section (AHNS) on Pediatric Benign and Malignant Thyroid Surgery

OBJECTIVES

To provide a clinical disease state review of recent relevant literature and to generate expert consensus statements regarding the breadth of pediatric thyroid cancer diagnosis and care, with an emphasis on thyroid surgery. To generate expert statements to educate pediatric practitioners on the state-of-the-art practices and the value of surgical experience in the management of this unusual and challenging disease in children.

METHODS

A literature search was conducted and statements were constructed and subjected to a modified Delphi process to measure the consensus of the expert author panel. The wording of statements, voting tabulation, and statistical analysis were overseen by a Delphi expert (J.J.S.).

RESULTS

Twenty-five consensus statements were created and subjected to a modified Delphi analysis to measure the strength of consensus of the expert author panel. All statements reached a level of consensus, and the majority of statements reached the highest level of consensus.

CONCLUSION

Pediatric thyroid cancer has many unique nuances, such as bulky cervical adenopathy on presentation, an increased incidence of diffuse sclerosing variant, and a longer potential lifespan to endure potential complications from treatment. Complications can be a burden to parents and patients alike. We suggest that optimal outcomes and decreased morbidity will come from the use of advanced imaging, diagnostic testing, and neural monitoring of patients treated at high-volume centers by high-volume surgeons.

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.

Surgical Management of Diffuse Sclerosing Variant of Papillary Thyroid Carcinoma. Experience in 25 Patients

PURPOSE

To delineate the clinicopathologic features and biologic behavior of the diffuse sclerosing variant of papillary thyroid carcinoma (DSV-PTC) and to report its outcome.

METHODS

The clinical records of 25 patients who had surgery for DSV-PTC from 2004 to 2017 were retrospectively analyzed. Comparisons were made to similar studies in the literature reporting ≥8 cases and a cohort of classical PTC.

RESULTS

There were 20 females and 5 males with an average age of 23 years (range 10-39 years). Bilateral disease occurred in 80% of cases. The mean size of the dominant mass was 4.2 ± 1.92 cm. In 92% of cases, therapeutic neck dissection was performed. Male sex significantly correlated with a higher yield of positive lymphadenopathy (p = 0.045). 62% of patients had recurrent disease. Recurrence significantly correlated with male sex, the number of metastatic lymph nodes (cutoff: 22 lymph nodes), and multifocality (p = 0.044, p ˂ 0.008, p ˂ 0.003, respectively). However, it did not correlate with the age at presentation. No disease-specific mortality occurred after an average follow-up of 77 months (range 12-168 months). The two comparisons made demonstrated a statistically significant greater tendency of the current series of DSV-PTC toward more aggressive clinicopathologic features and biologic behavior. No differences in overall survival were observed.

CONCLUSION

The DSV-PTC should be considered a high-risk PTC that mandates an aggressive therapeutic strategy with the intent of optimizing disease-free survival.

Molecular Aspects of Thyroid Calcification

In thyroid cancer, calcification is mainly present in classical papillary thyroid carcinoma (PTC) and in medullary thyroid carcinoma (MTC), despite being described in benign lesions and in other subtypes of thyroid carcinomas. Thyroid calcifications are classified according to their diameter and location. At ultrasonography, microcalcifications appear as hyperechoic spots ≤ 1 mm in diameter and can be named as stromal calcification, bone formation, or psammoma bodies (PBs), whereas calcifications > 1 mm are macrocalcifications. The mechanism of their formation is still poorly understood. Microcalcifications are generally accepted as a reliable indicator of malignancy as they mostly represent PBs. In order to progress in terms of the understanding of the mechanisms behind calcification occurring in thyroid tumors in general, and in PTC in particular, we decided to use histopathology as the basis of the possible cellular and molecular mechanisms of calcification formation in thyroid cancer. We explored the involvement of molecules such as runt-related transcription factor-2 (Runx-2), osteonectin/secreted protein acidic and rich in cysteine (SPARC), alkaline phosphatase (ALP), bone sialoprotein (BSP), and osteopontin (OPN) in the formation of calcification. The present review offers a novel insight into the mechanisms underlying the development of calcification in thyroid cancer.

Papillary Thyroid Cancer-Aggressive Variants and Impact on Management: A Narrative Review

Introduction

Aggressive variants of papillary thyroid cancer (PTC) have been described with increasing frequency. These variants include diffuse sclerosing variant, tall cell variant, columnar cell variant, solid variant, and hobnail variant.

Methods

We have performed a review of the more aggressive variants of PTC with respect to main characteristics, histological and molecular features, and the consequences that the knowledge of these variants should have in the treatment of the patients.

Results

At the present time, we do not know the prognostic value of these aggressive PTC variants. The extent of the surgical treatment and adjuvant therapy necessary should be decided on the basis of the extent of the tumor at presentation and the opinion of experienced clinicians.

Conclusion

These aggressive variants should be known by clinicians, to avoid underdiagnosis, and treated according to the latest recommendations in the literature.

Analysis of Malignant Thyroid Neoplasms with a Striking Rise of Papillary Microcarcinoma in an Endemic Goiter Region

According to National Cancer Registry Program, Thiruvananthapuram district of Kerala, has the highest relative frequency of thyroid carcinomas; nevertheless, limited data exist regarding its socio-demographic and clinico-pathological characteristics. The aims of the study were to assess the: (1) demographic characteristics, (2) histopathological features and the relative frequency of various thyroid carcinoma cases and papillary thyroid carcinoma (PTC) subtypes, (3) rising trend of papillary microcarcinomas, and (4) associated lesions. A retrospective study wherein 170 cases of thyroid malignancies reported in our single institution over a period of 8 years period was reviewed. PTC accounted for 97% cases, followed by medullary (n = 4; 2.4%) and follicular carcinoma (n = 1; 0.6%). There was female preponderance (p = 0.0379) with a lower median age in females (p = 0.0275). Among the PTCs, conventional type constituted 53.4% cases (n = 87), followed by microcarcinomas (n = 34; 20.9%), follicular variant (n = 28; 17.2%), and others 14 cases (8.5%). Thirty-three cases (19.4%) showed multifocality, 5 cases (2.9%) extra-thyroid extension, and 19 cases (11.2%) lymph node metastasis. Two cases developed recurrences and three cases, metastasis. The associated lesions were significantly higher in females (p = 0.0059); most common being multinodular goiter (MNG; n = 67; 41.1%), followed by Hashimoto thyroiditis (n = 44; 27%) and lymphocytic thyroiditis (n = 28; 17.2%); MNG being associated with follicular (p = 0.0129), and Hashimoto thyroiditis with conventional variant (p = 0.0475). The frequency of microcarcinomas significantly increased in the past 4 years (p = 0.0291) and was associated with MNG (p = 0.0055), Hurthle cell nodule (p = 0.0315) and absent lymph node metastasis (p = 0.0147). The primary treatment modality was total thyroidectomy. Papillary microcarcinoma cases increased significantly in the past 4 years and were significantly associated with MNG and Hurthle cell nodule. It is challenging to distinguish the various PTC subtypes as recognition of these histological variants warrants better patient management.

Influencers on Thyroid Cancer Onset: Molecular Genetic Basis

Thyroid cancer, a cancerous tumor or growth located within the thyroid gland, is the most common endocrine cancer. It is one of the few cancers whereby incidence rates have increased in recent years. It occurs in all age groups, from children through to seniors. Most studies are focused on dissecting its genetic basis, since our current knowledge of the genetic background of the different forms of thyroid cancer is far from complete, which poses a challenge for diagnosis and prognosis of the disease. In this review, we describe prevailing advances and update our understanding of the molecular genetics of thyroid cancer, focusing on the main genes related with the pathology, including the different noncoding RNAs associated with the disease.

Occult carcinoma confirmed to be a diffuse sclerosing variant of papillary thyroid carcinoma with unusual immunohistochemical features: A pitfall of clinicopathological diagnosis

Immunocytochemistry in a 78-year-old man diagnosed as having systemic metastatic cancer of unknown primary origin revealed atypical cells positive for napsin A and TTF-1, suggesting adenocarcinoma of the lung. However, there was no evidence of a primary lesion in the lung on positron emission tomography/computed tomography or at autopsy. Meanwhile, both the left and right thyroid lobes were firm and grayish white with marked fibrosis. Histology identified a diffuse sclerosing variant of papillary thyroid carcinoma that was positive for TTF-1 and napsin A but negative for PAX8. This disease entity is often misdiagnosed clinically as chronic thyroiditis. This is the first report of napsin A-positive and PAX8-negative thyroid carcinoma and highlights the pitfalls of clinicopathological diagnosis.

Integrin β4 promotes invasion and anoikis resistance of papillary thyroid carcinoma and is consistently overexpressed in lymphovascular tumor thrombus

Although the majority of papillary thyroid cancers (PTC) are indolent, a subset of PTCs behaves aggressively due to extensive invasion and distant metastasis. Integrin β4, a member of the integrin family, has been shown to enhance the progression in some malignancies; however, its role in PTC remains unclear. Here, we demonstrated that β4 overexpression was associated with extrathyroid extension, lymph node metastasis, high TNM stage, and poor overall survival based on The Cancer Genome Atlas cohort. Immunohistochemistry showed that β4 expression was significantly upregulated in the tumors with infiltrating growth pattern, as well as those with positive lymphovascular invasion. Moreover, β4 was invariably overexpressed in the lymphovascular tumor thrombi, which has not been reported before. After shRNA-induced knockdown of β4 in vitro, the migration, invasion and scratch repair ability of the tumor cells were significantly reduced. Furthermore, β4 reduction decreased anchorage-independent growth and increased anoikis. The bioinformatics analysis revealed that approximately 70 pathways were significantly dysregulated in the high β4 expression group. The MAPK pathway and propanoate metabolism were located in the network center of those pathways. Taken together, our results suggest that β4 could promote the tumor's aggressiveness by enhancing invasion and antagonizing anoikis. The upregulated expression of β4 in the tumor thrombi is intrinsically linked to its role in strengthening the anoikis resistance.

Prediction of the Prognosis Based on Chromosomal Instability-Related DNA Methylation Patterns of ELOVL2 and UBAC2 in PTCs

Papillary thyroid carcinoma (PTC) is the most common malignant tumor of endocrine systems. Chromosomal instability (CIN) is crucial to the clinical prognoses of tumor patients. DNA methylation plays an important role in the regulation of gene expression and CIN. Based on PTC samples from The Cancer Genome Atlas database, we used multiple regression analyses to identify methylation patterns of CpG sites with the strongest correlation with gene expression. A total of 4,997 genes were obtained through combining the CpG sites, which were represented as featured DNA methylation patterns. In order to identify CIN-related epigenetic markers of PTC survival, we developed a method to characterize CIN based on DNA methylation patterns of genes using the Student’s t statistics. We found that 1,239 genes were highly associated with CIN. With the use of the log-rank test, univariate Cox regression analyses, and the Kaplan-Meier method, DNA methylation patterns of UBAC2 and ELOVL2, highly correlated with CIN, provided potential prognostic values for PTC. The higher these two genes, risk scores were correlated with worse PTC patient prognoses. Moreover, the ELOVL2 risk score was significantly different in the four stages of PTC, suggesting that it was related to the progress of PTC. The DNA methylation pattern associated with CIN may therefore be a good predictor of PTC survival.

A case of Warthin-like papillary thyroid carcinoma with diffuse sclerosing stroma and a novel RET mutation: a new entity or a combined tumour?

Activating mutations of the RET gene have been described for both papillary (chromosomal rearrangement) and medullary (missense mutations) thyroid carcinomas. Here, we describe a case of a Warthin-like variant of papillary thyroid carcinoma displaying some morphological aspects that mimic the diffuse sclerosing variant. The tumour harboured BRAF V600E mutation and a novel germline point mutation in the RET gene, with unknown clinical and pathological meaning.

[Histopatological and molecular genetic characteristics of clinically aggressive variants of papillary thyroid carcinoma]

Papillary carcinoma is the most commonly diagnosed form of well-differentiated thyroid cancer that is generally characterized by a favorable prognosis. However, a number of relatively rare variants of this tumor, such as papillary carcinoma of high cells, papillary carcinoma of columnar cells, a diffuse sclerosing variant and recently described cancer of shoe nail cell type, are characterized by a less favorable clinical course, a high frequency of distant metastasis, and relatively low overall and relapse-free survival rates. In this connection, it is important to recognize these options at the stage of a primary morphological study. This review of the literature considers the morphological, clinical and molecular genetic features of the above variants of papillary thyroid carcinoma.

Cytologic features of aggressive variants of follicular-derived thyroid carcinoma

Certain carcinomas of the thyroid gland behave aggressively resulting in increased patient morbidity and poor patient prognosis. The diagnosis of these aggressive thyroid cancer subtypes is sometimes challenging and subject to increased interobserver variability. This review deals with the cytological features of such tumors including aggressive variants of papillary thyroid carcinoma, poorly differentiated thyroid carcinoma, and anaplastic thyroid carcinoma. These malignancies fall into 2 groups based on their cytomorphology: those that exhibit distinct microscopic features (eg, nuclear findings typical of classical papillary thyroid carcinoma or marked anaplasia) and those that present with more subtle cytologic features (eg, nuclear pseudostratification, "soap bubble" nuclei, supranuclear or subnuclear cytoplasmic vacuoles, rosette-like structures, hobnail cells). We review the literature regarding these aggressive thyroid cancers and highlight important phenotypic characteristics that can be useful for their diagnosis based on fine needle aspiration.

Does every classical type of well-differentiated thyroid cancer have excellent prognosis? A case series and literature review

Introduction: The classical type of well-differentiated thyroid cancer (WDTC) is the most common endocrine tumor with generally excellent prognosis. WDTC of the WHO stage 1 classification metastasizing to the vertebral column is not often seen for this neoplasm. Here, I present a case series of 14 individuals with aggressive classical type of WDTC. Methods: To identify the most aggressive cases of classical type WDTC, I reviewed the medical records of 4,327 patients consecutively admitted and surgically treated in a single institution for thyroid pathology in the years 2008-2016. Demographic, pathological and outcome data were collected and reviewed. Results: During the study period, 14 (4.02%) patients with aggressive forms of the classical type of WDTC were reviewed: 10 (2.87%) cases with papillary thyroid cancer (PTC) and 4 (1.14%) with follicular thyroid cancer (FTC). The median age at diagnosis was 61 years (31-84 years). Aggressive features such as extrathyroid extension 11/14 (78.57%), positive surgical margins 11/14 (78,57%), lymph node metastases 7/14 (50%), multifocality 6/14 (42.85%), regional tissue infiltration 11/14 (78.57%) and distant metastases 4/14 (28.57%) were observed. Long-term follow-up (median 40 months) demonstrated a high rate of locoregional recurrence in 12/14 (85.71%) individuals. Pulmonary and other distant metastases were observed in 4/14 (28.57%) patients, with mortality in 3/14 (21.42%) individuals. Conclusion: In patients with classical type of WDTC characterized by excellent prognosis, extremely aggressive entities might be observed, making WDTC in some cases an unpredictable tumor.

The Current Histologic Classification of Thyroid Cancer

Thyroid cancers of follicular cell derivation provide excellent phenotype-genotype correlations. Current morphologic classifications are complex and require simplification. Benign adenomas have follicular or papillary architecture and bland cytology. Well-differentiated thyroid carcinomas exhibit follicular architecture, expansile growth, and variable cytologic atypia and invasiveness; low-risk tumors have excellent prognosis after surgical resection whereas widely-invasive and angioinvasive tumors warrant total thyroidectomy and radioablation. Papillary carcinoma is less differentiated; indolent microcarcinomas can be managed by active surveillance, whereas clinical lesions with local or distant spread require therapy. Progression gives rise to poorly differentiated and anaplastic carcinomas that are less common but far more aggressive.

Survival of aggressive variants of papillary thyroid carcinoma in patients under 55 years old: a SEER population-based retrospective analysis

BACKGROUND

Patients younger than 55 years of age with papillary thyroid carcinoma (PTC) have excellent survival. Diffuse sclerosing variant (DSV) and tall cell variant (TCV) of PTC are associated with aggressiveness; the survival of patients <55 years of age with these variants is still unclear. We aim to investigate the clinicopathological features and survival of these variants in the age group <55 years.

METHODS

All adult patients (<55 years old) with DSV, TCV and conventional PTC (CPTC) came from the Surveillance, Epidemiology, and End Results program (1988-2013). Kaplan-Meier method and log-rank test were used to analyze the survival. Prognostic factors associated with survival were analyzed by Cox multivariate regression.

RESULTS

There were 280 DSV, 615 TCV, and 56287 CPTC in the age group <55 years. DSV and TCV were associated with multifocality, extrathyroidal extension, lymph node and distant metastasis (all p < 0.05). The 10-year disease-specific survival (DSS) of TCV was worse than CPTC (96.3 vs. 99.4%, p < 0.01), but there was no significant difference between DSV and CPTC (99.5 vs. 99.4%, p > 0.05). Cox multivariate regression showed TCV was the independent predictor of DSS (HR: 5.39, p < 0.01).

CONCLUSION

In the age group <55 years, DSV and TCV are more likely to exhibit aggressive characteristics than CPTC. Patient <55 years of age with DSV have excellent survival likewise, while patients <55 years of age with TCV carry worse survival. Further investigation for the recurrence risk of patients <55 years with these variants would contribute to optimal clinical management making.

Papillary Thyroid Carcinoma Incidentally Found in Cervical Lymph Nodes During Neck Dissection for Patients With Tongue Squamous Cell Carcinoma: A 3-Case Report and Literature Review

The incidence of papillary thyroid carcinoma (PTC) found in the cervical lymph nodes during neck dissection for patients with tongue squamous cell carcinoma (SCC) is infrequent, with the coexistence of PTC and SCC in the same cervical lymph node being the rarest. Some of these patients present with primary lesions in the thyroid gland, whereas others have no obviously malignant thyroid lesion. The reasons behind this clinical phenomenon and the relationship between tongue SCC and PTC found in the cervical lymph nodes are unclear. Moreover, for surgeons, making the choice between thyroid surgery and follow-up is still a clinical dilemma. Of the 956 patients who underwent neck dissection owing to maxillofacial tumors from January 2011 through December 2017 at Second Xiangya Hospital of Central South University, 3 with tongue SCC presented with PTC in the cervical lymph nodes. Neither the preoperative physical examination nor ultrasonography after surgery showed substantial nodules in the thyroid glands of these patients, so none of them underwent thyroid surgery or chemoradiotherapy. At follow-up (1 to 6.5 years), we found no obviously malignant lesions in the patients' thyroid glands or related metastatic disease. Our study suggests that tongue SCC may not affect the occurrence and development of PTC in the cervical lymph nodes. For patients with tongue SCC presenting with PTC in the cervical lymph nodes, it is not necessary to carry out thyroid surgery immediately if ultrasonography shows no substantially malignant lesion in the thyroid gland. Nevertheless, conducting periodic follow-up is very important.

Thyroid nodules and cancer in children and adolescents affected by Hashimoto's thyroiditis

OBJECTIVE

To investigate the rates of thyroid nodules and cancer in pediatric cases of Hashimoto's thyroiditis (HT) in Korea.

METHODS

We retrospectively reviewed 89 pediatric and adolescent patients (age, 3-18.0 years) with HT who underwent thyroid ultrasonography (US) at our institution from February 2006 to July 2016. The diagnosis of HT was based on the presence of thyroid autoantibodies. The presence of any thyroid nodules with US and cytopathologic features was analyzed. The malignancy rate was also determined.

RESULTS

Thyroid nodules were in 20 of the 89 patients (22.4%). Eight of these 20 patients (40%) had colloid cysts, two (10%) had nodular hyperplasia, one (5%) had follicular adenoma, and two (10%) had lymphocytic thyroiditis. Seven of the 89 patients (7.9%) were confirmed to have a malignancy, all of which were papillary thyroid carcinoma (PTC); of those, five patients had diffuse sclerosing variant PTC, and two had conventional PTC on pathology.

CONCLUSION

The prevalence of thyroid nodules in children and adolescents with HT was 22.4%. The malignancy rate of children with HT was 7.9%. The malignancy rate among thyroid nodules was 35%, which is higher than the 26% rate generally reported for children with nodules. Therefore, using thyroid US to survey known or suspected thyroid nodules might be helpful in children and adolescents with HT and may provide further useful diagnostic information. Advances in knowledge: Thyroid US could help to assess HT patients who have known or suspected thyroid nodules.