Papillary thyroid carcinoma with prominent myofibroblastic stromal component: clinicopathologic, immunohistochemical and next-generation sequencing study of seven cases

Papillary thyroid carcinoma with fibromatosis/fasciitis-like/desmoid-type stroma: When to suspect and how to diagnose

Currently, it is known that more than 60% of adults have one or more thyroid nodules, of which less than 5% are malignant. Among them, papillary thyroid carcinoma (PTC) is the most common thyroid malignancy, accounting for 90% of all thyroid carcinomas. The World Health Organization (WHO) 5th edition endocrine tumours classification includes several PTC subtypes. Of these, PTC with fibromatosis/fasciitis-like/desmoid-type stroma stands out not only for being one of the least frequent subtypes but also for its characteristic histology (biphasic structure) and genetic pattern, which presents mutations in both BRAF and CTNNB1. Despite these distinctive features, it remains a challenging neoplasm to suspect and easy to misdiagnose, primarily due to its radiological imaging and cytological findings. In this study, we report a classic case, review the literature, discuss when suspicion should arise, and provide a practical diagnostic guide.

Next-Generation Immunohistochemistry in Thyroid Neoplasm: A Practical Review on the Applications in Diagnosis and Molecular Classification

An integrative histologic and molecular classification of thyroid tumors has become clinically relevant due to the potential role in risk stratification and selection of targeted therapy. In this review, we discuss the applications of six "next-generation" immunohistochemical markers, namely BRAF V600E (clone VE1), RAS Q61R (clone SP174), pan-TRK (clone EPR 17341), ALK (clones 5A4 or D5F3), PTEN, and β-catenin in the pathologic diagnosis and molecular classification of thyroid tumors. These biomarkers allow the in situ examination of tumor tissue and assist in the diagnosis and pathologic staging by highlighting tumor border and patterns of invasion, identifying isolated tumor cells in lymph nodes, distinguishing lymph node metastasis from benign intranodal thyroid inclusions, and diagnosing multicentric thyroid carcinomas with discordant molecular drivers. Furthermore, it can identify specific thyroid neoplasms that may occur sporadically or may be associated with hereditary syndromes. The next-generation immunohistochemistry provides a novel solution to challenging issues in thyroid pathology and fast turn-around time for accurate molecular classification and further guidance of therapeutic management.

Papillary Thyroid Carcinoma with Fibromatosis/Fasciitis-Like/Desmoid-Type Stroma: Case Report of a Rare Subtype with Cytological and Molecular Study

BACKGROUND

Papillary thyroid carcinoma (PTC) with fibromatosis/fasciitis-like/desmoid-type stroma is a rare subtype of PTC,characterized by two distinct components: a classic papillary carcinoma component and a spindle cell proliferationresembling fibromatosis or nodular fasciitis. This stromal component adds a unique dimension to the tumor'spathology, making diagnosis more challenging and potentially leading to misclassification.

CASE PRESENTATION

We present a case of this rare entity which contributes to the growing body of literature by providing additionalmolecular data, which may shed light on the biological behaviour of the fibromatosis-like stroma and its relationshipwith the papillary carcinoma component. This case underscores the importance of recognizing this subtype, as itsspindle cell proliferation could be mistaken for a separate neoplasm or reactive process, resulting in inappropriatemanagement.

CONCLUSIONS

Increased awareness of this entity will help pathologists avoid diagnostic pitfalls and guide clinicians in developingmore precise treatment plans, addressing both the malignant papillary component and the unique stromal features.This case further enriches the current understanding of the heterogeneity of PTC and highlights the need fortailored management strategies in rare subtypes.

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.

Papillary thyroid carcinoma with nodular fasciitis-like stroma - an unusual variant with distinctive histopathology: A case report

BACKGROUND

Papillary thyroid carcinoma (PTC) is regarded as a fairly common endocrine malignancy, which can be divided into different multiple variants due to wide morphologic differences. The majority of PTC variants have been reported, but PTC with nodular fasciitis-like stroma (NFS) is a rare pathological variant and has been infrequently reported in the relevant literature. This condition involves abundant reactive stromal components rich in spindle cells, which may account for 60%-80% of the tumor along with a typical papillary carcinoma.

CASE SUMMARY

A 44-year-old man presented with a 4-mo history of a palpable mass over the anterior aspect of the left neck, the tumor demonstrated gradual enlargement but was painless during the 4 mo prior to discovery. Thyroid function test results were normal. Physical examination showed an enormous and firm nodular mass in the left lobe of the thyroid gland extending to the level of the hyoid bone. Ultrasonography of the neck revealed a well-defined heterogeneous lesion measuring around 5.0 cm × 4.0 cm with a hypoechoic complex nodule, decreased vascularity and speckles of microcalcification. The patient underwent left thyroidectomy with central compartment lymph node dissection. Final histopathological examination confirmed the diagnosis of PTC with extensive fibromatosis-like stroma combined with typical PTC. The patient was asymptomatic at the 3-mo follow-up.

CONCLUSION

PTC-NFS is a rare pathological variant and its diagnosis and prognosis may be similar to typical papillary carcinoma.

Papillary thyroid carcinoma with fibromatosis-like stroma: a case report and review of the literature

BACKGROUND

Papillary thyroid carcinoma (PTC) is a common neoplasia with multiple variants. One of these extremely rare and poorly described variants is PTC with fibromatosis-like stroma (PTC-FMS), a peculiar entity distinguished by its predominant mesenchymal component. This paper reviews the literature, discusses the diagnostic challenges, and the clinical and surgical implications of this type of tumor which has fewer than 30 cases reported in the literature.

CASE PRESENTATION

We reported a case of PTC-FMS found in a 41-year-old Italian woman, who came to our Institute with a recent growth in the form of a mass on the neck. Further immunohistochemical examination showed β-catenin aberrant staining both in the nuclei and cytoplasm of the mesenchymal cells. The patient underwent total thyroidectomy and received radioactive iodine (RAI) 2 months after surgery.

CONCLUSION

Given the possibility of recurrence of PTC-FMS and the ineffectiveness of RAI therapy, complete surgical resection represents the main treatment for this type of tumor. Despite the fact that the specific nature of these lesions has yet to be determined, guidelines for classical PTC should be followed.

Papillary thyroid carcinoma with desmoid-type fibromatosis: the clinicopathological features with characteristic imaging and molecular correlation requiring comprehensive treatment

The pathogenesis and treatment of papillary thyroid cancer with desmoid-type fibromatosis (PTC-DTF), a rare subtype of papillary thyroid carcinoma characterized by a mixed epithelial-mesenchymal structure, are still ill-defined. Previous reports on PTC-DTF have had limited follow-up and recurrence has been rarely reported. To better understand this condition, we conducted a thorough analysis of five cases of PTC-DTF from our institute, including clinical and pathological examinations, imaging, immunohistochemistry, and molecular analysis. We also reviewed relevant literature. The mean age of the patients was 51.8 years, with three women and two men included in the group. Ultrasound often showed a hypoechogenic and well-defined nodule in the thyroid gland, except for one individual who had distant lung metastases detected by PET-CT. The nodules ranged in width from 0.5 to 5.0 cm and were excised in each case. Following surgery, ¹³¹I therapy was used in two cases. The overall number of PTC-DTF cases has risen from the previously reported 55 to 60, with females being the most commonly affected and ranging in age from 19 to 82. Most masses underwent a thyroidectomy, and approximately half of the patients had lymph node metastases. Histologically, PTC-DTFs were composed of a predominant stromal component (65% - 90%) and an intervening epithelial component. These spindle cells were arranged in parallel with abundant cytoplasm and vacuole-like nucleus but there wasn't evident atypia. The carcinoma cells were positively stained for CK and TTF-1 by immunohistochemistry, whereas mesenchymal cells were positive for SMA and displayed nuclear immunoreactivity for β-catenin. BRAF, NRAS, and CTNNB1 mutations were identified in the epithelial and mesenchymal components through molecular testing, respectively. Perhaps because the mesenchyme harbors aberrant nuclear β-catenin expression, PTC-DTF is more aggressive and prone to invasion and distant recurrence, as shown by our case 2, which is the first case to be reported thus far. PTC-DTF is typically treated with surgery, but clinicians may occasionally consider more holistic treatment plans that involve radioactive iodine and endocrine therapy.

Molecular Landscape of Pediatric Thyroid Cancer: A Review

Thyroid carcinomas (TC) are rare in the pediatric population; however, they constitute the most common endocrine malignancy. Despite some similarities with adult carcinomas, they have distinct clinical behavior and responses to therapy due to their unique pathology and molecular characteristics. The age cut-off used for defining the pediatric age group has been variable across different studies, and the universally accepted recommendations influence accurate interpretation of the available data. Moreover, factors such as radiation exposure and germline mutations have greater impact in children than in adults. Papillary TC is the most common and the most evaluated pediatric TC. Others, including follicular, poorly differentiated and medullary carcinomas, are rarer and have limited available literature. Most studies are from the West. Asian studies are primarily from Japan, with few from China, India, Saudi Arabia and Republic of Korea. This review provides a comprehensive account of the well-established and novel biomarkers in the field, including point mutations, fusions, miRNA, and thyroid differentiation genes. Familial and syndromic associations are also discussed. Current management guidelines for pediatric patients are largely derived from those for adults. An awareness of the molecular landscape is essential to acknowledge the uniqueness of these tumors and establish specific diagnostic and therapeutic guidelines.

Cell Component and Function of Tumor Microenvironment in Thyroid Cancer

Thyroid cancer is the most common cancer in the endocrine system. Most thyroid cancers have good prognosis, but some of them are resistant to treatment or show aggressive behavior. Like other tumors, thyroid cancers harbor tumor microenvironment (TME) composed of cancer associated fibroblasts (CAF) and immune cells. Autoimmune lymphocytic thyroiditis can occur in the thyroid, and it may be associated with cancer development. TME is involved in tumor progression through various mechanisms: (1) CAF is involved in tumor progression through cell proliferation and extracellular matrix (ECM) remodeling; and (2) immune cells are involved in tumor progression through cell proliferation, angiogenesis, epithelial mesenchymal transformation (EMT), and immune suppression. These events are activated by various cytokines, chemokines, and metabolites secreted from cells that comprise TME. This review is focused on how CAF and immune cells, two important cell components of thyroid cancer TME, are involved in tumor progression, and will explore their potential as therapeutic targets.

Papillary Thyroid Carcinoma with Desmoid-Type Fibromatosis: Review of Published Cases

Simple Summary

Papillary thyroid cancer (PTC)-desmoid type fibromatosis (DTF) is one of the rarest variants of PTC. The diagnosis is histological, and detecting a mutation of CTNNB1 in the mesenchymal component is highly suggestive of PTC-DTF. The treatment is essentially surgical. We conducted a review of all cases of PTC-DTF found in the English literature and our aim is to describe patient’s characteristics, histology, immunohistochemistry and somatic mutations of every case.

Abstract

Desmoid-type fibromatosis (DTF) is a very rare variant of papillary thyroid carcinoma (PTC). It is essentially a dual tumor with a component of classical PTC with malignant epithelial proliferation (BRAF-mutated) and another component of mesenchymal proliferation (CTNNB1-mutated). We conducted a literature review on PTC-DTF. In total, 31 articles were identified, that together reported on 54 patients. The mean age was 47 years, with a 2.2:1 female predominance. No ultrasound features were found to be helpful in differentiating PTC-DTF from other PTC variants. Of the 43 cases that reported histological details, 60% had locally infiltrative disease (T3b or T4). Around 48% had cervical lymph node metastases, but none had distant metastases. While PTC-DTF may be locally more aggressive than classic PTC, its overall behavior is similar and can include extrathyroidal extension and lymph node metastases, which may contain a stromal component and show extranodal invasion. The mainstay of treatment for PTC-DTF is surgery, and the DTF component is not expected to be sensitive to radioactive iodine. External radiotherapy, non-steroidal anti-inflammatory drugs, tyrosine kinase inhibitors and chemotherapy have also been used in selected cases. Due to the rarity of these tumors and the lack of specific treatment guidelines, management should be discussed in a multidisciplinary team.

Papillary thyroid carcinoma with nodular fasciitis-like stroma: a rare variant

Papillary thyroid carcinoma with desmoid-type fibromatosis (PTC-DTF) or nodular fasciitis-like stroma (PTC-NFS) is a rare morphological variant of PTC with a favorable prognosis. There is a paucity of molecular data regarding this entity. We present the case of a 20-year-old female who presented with a palpable mass over the anterior aspect of the neck for the past 3–4 months, which was diagnosed as PTC-NFS. Ultrasonogram of the neck revealed a bulky left lobe of thyroid that contained a well-defined heterogenous lesion measuring around 24 × 26 × 36 mm with involvement of the adjacent isthmus. She underwent a total thyroidectomy with central compartment lymph node dissection. Histological examination revealed a biphasic tumor with epithelial and stromal components resembling nodular fasciitis. Two dissected lymph nodes showed metastasis of the epithelial component only. On immunohistochemistry, BRAF mutant protein expression was evident in the epithelial component only, while β-catenin was negative in both the components. The histopathological diagnosis of papillary thyroid carcinoma with nodular fasciitis-like stroma was offered. Sanger sequencing revealed a BRAFV600E (c.1799T>A, Val600Glu) mutation. Post-operatively, no residual tumor was detected on ultrasound and radioiodine scans. The patient was doing well at follow-up of 9 months. PTC-NFS/DTF is a histological variant of PTC with a favorable prognosis. Our index case was associated with the BRAF mutation, which was restricted to the epithelial component. Thorough sampling of the excised specimen is essential in order not to miss the epithelial component, which, in most reported cases (including ours) appears to be small.

Cytologic and histological features of rare nonepithelial and nonlymphoid tumors of the thyroid

Thyroid tumors can be classified into epithelial, nonepithelial, and nonprimary lesions. Nonepithelial thyroid tumors are rare. They can be of primary origin within the thyroid gland, arise secondary to contiguous growth from adjacent tissues, or represent metastatic disease. The incidence of nonepithelial tumors of the thyroid is only 1% to 2%, most of which are lymphomas; the remainder includes mesenchymal and histiocytic tumors. This review examines the cytohistological features of various nonepithelial and nonlymphoid tumors of the thyroid, including vascular lesions, neural tumors (including granular cell tumor and paraganglioma), smooth muscle tumors, solitary fibrous tumor, histiocytic neoplasms (eg, Langerhans cell histiocytosis and Rosai-Dorfman disease), and follicular dendritic cell sarcoma. Their differential diagnosis is discussed, including recommendations to prevent the pitfall of mistaking these rare tumors for more common epithelial thyroid neoplasms.

Research Progress of TXNIP as a Tumor Suppressor Gene Participating in the Metabolic Reprogramming and Oxidative Stress of Cancer Cells in Various Cancers

Thioredoxin-interacting protein (TXNIP) is a thioredoxin-binding protein that can mediate oxidative stress, inhibit cell proliferation, and induce apoptosis by inhibiting the function of the thioredoxin system. TXNIP is important because of its wide range of functions in cardiovascular diseases, neurodegenerative diseases, cancer, diabetes, and other diseases. Increasing evidence has shown that TXNIP expression is low in tumors and that it may act as a tumor suppressor in various cancer types such as hepatocarcinoma, breast cancer, and lung cancer. TXNIP is known to inhibit the proliferation of breast cancer cells by affecting metabolic reprogramming and can affect the invasion and migration of breast cancer cells through the TXNIP-HIF1α-TWIST signaling axis. TXNIP can also prevent the occurrence of bladder cancer by inhibiting the activation of ERK, which inhibits apoptosis in bladder cancer cells. In this review, we find that TXNIP can be regulated by binding to transcription factors or other binding proteins and can also be downregulated by epigenetic changes or miRNA. In addition, we also summarize emerging insights on TXNIP expression and its functional role in different kinds of cancers, as well as clarify its participation in metabolic reprogramming and oxidative stress in cancer cells, wherein it acts as a putative tumor suppressor gene to inhibit the proliferation, invasion, and migration of different tumor cells as well as promote apoptosis in these cells. TXNIP may therefore be of basic and clinical significance for finding novel molecular targets that can facilitate the diagnosis and treatment of malignant tumors.