Multifocal fibrosing thyroiditis and its association with papillary thyroid carcinoma using BRAF pyrosequencing

Immune response and mesenchymal transition of papillary thyroid carcinoma reflected in ultrasonography features assessed by radiologists and deep learning

INTRODUCTION

Ultrasonography (US) features of papillary thyroid cancers (PTCs) are used to select nodules for biopsy due to their association with tumor behavior. However, the molecular biological mechanisms that lead to the characteristic US features of PTCs are largely unknown.

OBJECTIVES

This study aimed to investigate the molecular biological mechanisms behind US features assessed by radiologists and three convolutional neural networks (CNN) through transcriptome analysis.

METHODS

Transcriptome data from 273 PTC tissue samples were generated and differentially expressed genes (DEGs) were identified according to US feature. Pathway enrichment analyses were also conducted by gene set enrichment analysis (GSEA) and ClusterProfiler according to assessments made by radiologists and three CNNs - CNN1 (ResNet50), CNN2 (ResNet101) and CNN3 (VGG16). Signature gene scores for PTCs were calculated by single-sample GSEA (ssGSEA).

RESULTS

Individual suspicious US features consistently suggested an upregulation of genes related to immune response and epithelial-mesenchymal transition (EMT). Likewise, PTCs assessed as positive by radiologists and three CNNs showed the coordinate enrichment of similar gene sets with abundant immune and stromal components. However, PTCs assessed as positive by radiologists had the highest number of DEGs, and those assessed as positive by CNN3 had more diverse DEGs and gene sets compared to CNN1 or CNN2. The percentage of PTCs assessed as positive or negative concordantly by radiologists and three CNNs was 85.6% (231/273) and 7.1% (3/273), respectively.

CONCLUSION

US features assessed by radiologists and CNNs revealed molecular biologic features and tumor microenvironment in PTCs.

Multifocal Fibrosing Thyroiditis: an Under-recognized Mimicker of Papillary Thyroid Carcinoma

Multifocal fibrosing thyroiditis (MFT) is an enigmatic entity, characterized by multiple fibrotic scar-like lesions with a paucicellular fibrotic center surrounded by a cellular peripheral area with reactive-appearing follicular cell atypia and variable chronic inflammation. Although poorly recognized and likely underreported in surgical pathology, the entity is considered rare with only 65 cases to date-including the current one reported to expand on the preoperative findings of this under-recognized entity. The average age of the patients is 46.8 years (range 15-71 years), 94% are female, with female to male ratio of 15:1. Individual MFT lesions typically have a superficial location. The average number of fibrotic lesions is 15.4 (range 2-51 per MFT case). Their average size is 3.1 mm (range 0.4-15.1). MFT is a disorder of diseased thyroids, typically found postoperatively in glands removed for other reasons, such as chronic lymphocytic/Hashimoto thyroiditis (32.3%), follicular nodular disease (nodular hyperplasia) (30.1%), hyperthyroidism/diffuse hyperplasia (Graves disease) (9.2%). Intriguing is the association with papillary thyroid carcinoma-present in 38.5% of MFT cases, and particularly with sub-centimetric and multifocal papillary thyroid carcinoma, with which MFT can be confused. Cases where MFT is the only thyroid pathology (7.7%) can be preoperatively mistaken for papillary thyroid carcinoma, due to worrisome ultrasound (US) and cytologic features, both of which are here documented for the first time as a component of this article. Wider recognition of MFT and of its cytologic and ultrasound features at preoperative evaluation may reduce unnecessary thyroidectomies.

Molecular Neuropathology in Practice: Clinical Profiling and Integrative Analysis of Molecular Alterations in Glioblastoma

Molecular profiling of glioblastoma has revealed complex cytogenetic, epigenetic, and molecular abnormalities that are necessary for diagnosis, prognosis, and treatment. Our neuro-oncology group has developed a data-driven, institutional consensus guideline for efficient and optimal workup of glioblastomas based on our routine performance of molecular testing. We describe our institution’s testing algorithm, assay development, and genetic findings in glioblastoma, to illustrate current practices and challenges in neuropathology related to molecular and genetic testing. We have found that coordination of test requisition, tissue handling, and incorporation of results into the final pathologic diagnosis by the neuropathologist improve patient care. Here, we present analysis of O⁶-methylguanine-DNA-methyltransferase promoter methylation and next-generation sequencing results of 189 patients, obtained utilizing our internal processes led by the neuropathology team. Our institutional pathway for neuropathologist-driven molecular testing has streamlined the management of glioblastoma samples for efficient return of results for incorporation of genomic data into the pathological diagnosis and optimal patient care.

Building a Robust Tumor Profiling Program: Synergy between Next-Generation Sequencing and Targeted Single-Gene Testing

Next-generation sequencing (NGS) is a powerful platform for identifying cancer mutations. Routine clinical adoption of NGS requires optimized quality control metrics to ensure accurate results. To assess the robustness of our clinical NGS pipeline, we analyzed the results of 304 solid tumor and hematologic malignancy specimens tested simultaneously by NGS and one or more targeted single-gene tests (EGFR, KRAS, BRAF, NPM1, FLT3, and JAK2). For samples that passed our validated tumor percentage and DNA quality and quantity thresholds, there was perfect concordance between NGS and targeted single-gene tests with the exception of two FLT3 internal tandem duplications that fell below the stringent pre-established reporting threshold but were readily detected by manual inspection. In addition, NGS identified clinically significant mutations not covered by single-gene tests. These findings confirm NGS as a reliable platform for routine clinical use when appropriate quality control metrics, such as tumor percentage and DNA quality cutoffs, are in place. Based on our findings, we suggest a simple workflow that should facilitate adoption of clinical oncologic NGS services at other institutions.

Overlapping Morphologic and Immunohistochemical Features of Hashimoto Thyroiditis and IgG4-Related Thyroid Disease

Immunoglobulin G4-related disease (IgG4-RD) is an emerging clinicopathologic entity characterized by both IgG4+ plasma cell infiltration and fibrosis in one or more organs, prototypically pancreas or salivary/lacrimal glands. IgG4-RD in the thyroid (IgG4-RTD) is an area of active study, and the relationship between IgG4-RTD and Hashimoto thyroiditis is not fully delineated due to their overlapping histologic features. Retrospective review was performed of all thyroidectomy cases demonstrating lymphocytic inflammation at a single institution over a 4-year period. Approximately half (23/38) of patients had a clinical diagnosis of Hashimoto thyroiditis (HT). Nine of the 38 patients had increased absolute and relative numbers of IgG4+ plasma cells. Patients with a clinical diagnosis of HT had increased lymphoplasmacytic inflammation, but the relative proportion of IgG4+ plasma cells was not increased compared to patients without HT. There was no correlation between IgG4 levels and the amount of fibrosis in patients with or without HT. Patients identified as having the fibrosing variant of HT were not more likely to have increased levels of IgG4+ plasma cells than those without. There is significant morphologic and immunohistochemical overlap between HT and IgG4-RTD. Future studies to identify specific characteristics of IgG4-RTD involving the thyroid are necessary to accurately define this entity.

Multifocal fibrosing thyroiditis: report of 55 cases of a poorly recognized entity

During the course of our consultation activity, we have recognized a peculiar form of thyroiditis in which multiple foci of fibrosis, most of which were associated with reactive atypia of the surrounding follicles, are present. We have referred to this condition, both in our consultation reports and in the third series of A.F.I.P. Fascicle on Tumors of the Thyroid Gland, as "multifocal fibrosing thyroiditis" or (less frequently) "multifocal sclerosing thyroiditis," which are descriptive terms that highlight the benign/inflammatory nature of the process, its multiplicity, and its unknown pathogenesis. The aim of this study is to better define the morphologic features of this process and correlate it with some clinical data. With this purpose, the consultation files of one of the authors (J.R.) were searched for cases coded as multifocal fibrosing thyroiditis or multifocal sclerosing thyroiditis in a 20-year period ranging from January 1989 to December 2009. A total of 55 cases were identified that displayed the above-listed features. There were 51 (93%) female and 4 (7%) male patients (F/M=12.75), with ages ranging between 15 and 71 years (mean age, 47.03 y; median age, 44.5 y). Microscopically, multiple foci of fibrosis were identified in all cases, their number ranging from 2 to 51 per case (mean number, 16), with a mean diameter of 3 mm (range: 0.36 to 15.1 mm). Although heterogenous in shape and size, the individual foci were rather similar to each other in composition, being characterized by a fibrotic poorly cellular center that merged with a cellular peripheral zone. Some of the follicular structures present at the periphery of the scar and-to a lesser extent-those entrapped inside it underwent complex reactive and regenerative (atypical) changes that simulated malignancy. We discuss the differential diagnosis with other benign and malignant thyroid conditions and speculate about its pathogenesis and possible relationship with papillary thyroid microcarcinoma.