Soft tissue reporting and data system (soft tissue-RADS): framework for radiologists specializing in imagingof musculoskeletal tumors and tumor-like lesions.

WHO classification of soft tissue tumours 2020: An update and simplified approach for radiologists

The purpose of this study: Musculoskeletal tumors are very rare, and their distribution varies regionally. We aim to share the musculoskeletal system tumors and tumor-like lesions that orthopedic surgeons in the region commonly encounter in their daily practice.Methods. In this retrospective study, 339 patients diagnosed with tumor and tumor-like lesions in the musculoskeletal system who consulted a single orthopedic surgeon between 2022 and 2023 in a tertiary hospital in the Southeast of the country were included. Age, gender, size, type of lesions, tumor diagnoses, and anatomical sites were examined.Results. Bone localization (62.8%) is more common than soft tissue. Benign lesions are most commonly seen in both bone and soft tissue. Osteochondroma (21.7%) and chondrosarcoma (54%) are the most common benign and malignant bone tumors, while osteomyelitis (47.6%) is the most common tumor-like lesion. Hemangioma (27%) and peripheral nerve sheath tumor (62.5%) are the most common benign and malignant soft tissue tumors, while ganglion cyst (63.8%) is the most common tumor-like lesion. Benign bone tumors are larger in males than females (p:0.008). Lower extremity located of musculoskeletal tumors and tumor-like lesions is more common than upper extremity.Conclusions. In the Southeastern Anatolia region, benign bone and soft tissue tumors (osteochondroma and hemangioma) are more likely. The most common malignant tumors are chondrosarcoma and peripheral nerve sheath tumors. Additionally, it should not be forgotten that musculoskeletal system tumors are often located in the lower extremities.Keywords: Benign tumors, bone tumors, malign tumors, musculoskeletal tumors, soft tissue tumors, tumor-like lesions.Corresponding author: Özlem Orhan, Assistant professor of the Department of Orthopedics and Traumatology, Medical Faculty, Harran University, Sanlıurfa, Turkey. Postal code: 63300Address: Turkey, Sanlıurfa, Osmanbey campusPhone: +905057475401Email: droorhan@gmail.comJ Trauma Ortho Kaz 2023; 3 (69): 12-18Recieved: 28-07-2023Accepted: 11-09-2023 This work is licensed under a Creative Commons Attribution 4.0 International License

The World Health Organisation (WHO) classification categorises musculoskeletal soft tissue tumours (STT) based on their similarity to normal adult tissue. The most recent WHO classification provides an updated scheme that integrates biological behaviour as a distinguishing feature in each subcategory; STTs are further subdivided as benign, intermediate (locally aggressive or rarely metastasising), and malignant. Although malignant STTs are infrequent in routine orthopaedic radiology practice, musculoskeletal radiologists must be familiar with the imaging appearance of malignant STTs and distinguish them from their benign counterparts for appropriate management. Magnetic resonance imaging (MRI) is the ideal modality for the detection, characterisation, and local staging of STT. This review will discuss the most recent updates to the WHO classification of STT that are relevant to radiologists in a routine clinical practice with MRI correlation. The utility of advanced MRI sequences such as diffusion weighted imaging, dynamic contrast enhanced sequences, and magnetic resonance spectroscopy to provide insight into the biological behaviour of various STTs is highlighted.

Background:In 2020, the World Health Organization (WHO) published the 5th version of the soft tissue and bone tumor classification. Based on this novel classification system, we reviewed the current knowledge on all tumor entities with spinal manifestations, their biologic behavior, and most importantly the appropriate treatment options as well as surgical approaches.Methods:All tumor entities were extracted from the WHO Soft-Tissue and Bone Tumor Classification (5th Edition). PubMed and Google Scholar were searched for the published cases of spinal tumor manifestations for each entity, and the following characteristics were extracted: Growth pattern, ability to metastasize, peak age, incidence, treatment, type of surgical resection indicated, recurrence rate, risk factors, 5-year survival rate, key molecular or genetic alterations, and possible associated tumor syndromes. Surgical treatment strategies as well as nonsurgical treatment recommendations are presented based on the biologic behavior of each lesion.Results:Out of 163 primary tumor entities of bone and soft tissue, 92 lesions have been reported along the spinal axis. Of these 92 entities, 54 have the potential to metastasize. The peak age ranges from conatal lesions to 72 years. For each tumor entity, we present recommended surgical treatment strategies based on the ability to locally destruct tissue, to grow, recur after resection, undergo malignant transformation as well as survival rates. In addition, potential systemic treatment recommendations for each tumor entity are outlined.Conclusion:Based on the 5th Edition of the WHO bone and soft tumor classification, we identified 92 out of 163 tumor entities, which potentially can have spinal manifestations. Exact preoperative tissue diagnosis and interdisciplinary case discussions are crucial. Surgical resection is indicated in a significant subset of patients and has to be tailored to the specific biologic behavior of the targeted tumor entity based on the considerations outlined in detail in this article.

SummaryMesenchymal tumours represent one of the most challenging field of diagnostic pathology and refinement of classification schemes plays a key role in improving the quality of pathologic diagnosis and, as a consequence, of therapeutic options. The recent publication of the new WHO classification of Soft Tissue Tumours and Bone represents a major step toward improved standardization of diagnosis. Importantly, the 2020 WHO classification has been opened to expert clinicians that have further contributed to underline the key value of pathologic diagnosis as a rationale for proper treatment. Several relevant advances have been introduced. In the attempt to improve the prediction of clinical behaviour of solitary fibrous tumour, a risk assessment scheme has been implemented. NTRK-rearranged soft tissue tumours are now listed as an “emerging entity” also in consideration of the recent therapeutic developments in terms of NTRK inhibition. This decision has been source of a passionate debate regarding the definition of “tumour entity” as well as the consequences of a “pathology agnostic” approach to precision oncology. In consideration of their distinct clinicopathologic features, undifferentiated round cell sarcomas are now kept separate from Ewing sarcoma and subclassified, according to the underlying gene rearrangements, into three main subgroups (CIC, BCLR and not ETS fused sarcomas) Importantly, In order to avoid potential confusion, tumour entities such as gastrointestinal stroma tumours are addressed homogenously across the different WHO fascicles. Pathologic diagnosis represents the integration of morphologic, immunohistochemical and molecular characteristics and is a key element of clinical decision making. The WHO classification is as a key instrument to promote multidisciplinarity, stimulating pathologists, geneticists and clinicians to join efforts aimed to translate novel pathologic findings into more effective treatments.

The article provides an overview of the main changes in the current (2020) WHO classification of soft tissue tumors, as well as selected updates that have occurred since the release of the classification.

Aims:The aim of this study is to evaluate the data belonging to patients who were diagnosed with benign or malignant soft tissue and bone tumors and tumor-like lesions evaluated by musculoskeletal tumor study group of Trakya University Faculty of Medicine in between January 2013 and June 2017 and the relationship between the frequency of benign, malignant bone and soft tissue tumors and tumor-like lesions, with the patients' age and gender. Methods:The data of 687 patients who were evaluated by the musculoskeletal tumor study group of Trakya University Faculty of Medicine between January 2013-June 2017 were analyzed retrospectively.All of the data was analyzed by using SPSS.Chi-square analysis was used to obtain categorical data in order to point out the distribution of age and gender of patients with musculoskeletal system tumors and tumor-like lesions. Results:The number of patients over the period from January 2013 to June 2017 was 687.The number of patients who were evaluated by biopsy and acquired histopathologic confirmation of their condition was 341.The mean of patients' ages was 44.3±21.4(4-92).Among 341 patients, 106 (47.1%) patients were female and 119 (52.9%) patients were male.The mean of females' ages was 43.7±20.4(4-92).The mean of males' ages was 44.7±22.4(5-90). Conclusion:Benign bone and soft tissue tumors were more common than malignant tumors.Benign bone tumors were predominantly seen in young adults.Our results was consistent with the literature however due to some patients who did not need a pathological sampling, our sample size was smaller than intended.With better archived information, more consistent results could be obtained in further studies.

Pictorial essay on selected new, emerging, and reclassified entities in the 2020 WHO classification of soft tissue tumors.

Progress in our understanding of the pathogenesis and diagnosis of soft tissue neoplasia is exceptionally rapid. Although the most recent World Health Organization classification of soft tissue tumours contains many new entities and refinements of older ones, even this comprehensive document is by now incomplete or in need of modification. This review will attempt to summarise the developments in soft tissue pathology that have occurred since 2020, emphasising lesions for which morphology and genetics intersect in a complementary fashion. Novel entities discussed include KMT2A-rearranged sarcoma, PRRX::NCOAx fibroblastic tumours, EWSR1::PATZ1 sarcomas, BRAF-altered infantile fibrosarcoma-like lesions, NUTM1-rearranged colorectal sarcomas, and a variety of interesting giant cell-rich and matrix-producing lesions. In addition, recently described mimics of atypical lipomatous tumour/well-differentiated liposarcoma are covered, as is a wholly new, morphologically defined and genetically confirmed entity, pseudoendocrine sarcoma. Finally, exciting new developments in the use of immunohistochemistry as a surrogate for molecular genetic techniques are discussed.

The mediastinum is a defined anatomic space in which organs and major blood vessels reside with admixed soft tissue elements. Many of the masses encountered in the mediastinum are related to the thymus. Most neoplasms diagnosed in the mediastinum are epithelial tumors (thymomas and thymic carcinomas), lymphomas, or germ cell tumors. In contrast, soft tissue tumors of the mediastinum are rare. Because of their rarity, most mesenchymal tumors in the mediastinum have been reported as case reports or small series. Mediastinal soft tissue tumors encompass the wide spectrum of soft tissue tumors that occur in other locations with lipomatous and neurogenic tumors comprising some of the most common types. In addition to primary sarcomas of the mediastinum, secondary “somatic-type” malignancy may occur in a mediastinal germ cell tumor. Development of a sarcomatous component has been reported to occur more frequently in mediastinal germ cell tumors than in other sites. This chapter will emphasize on the primary mesenchymal tumors of the mediastinum in accordance with the current WHO classification of soft tissue tumors.

Soft tissue tumors are avery heterogeneous group of tumors. Their classification is regularly updated by the World Health Organization (WHO), most recently in 2020. The current classification of soft tissue tumors emphasizes molecular biological tumor characteristics, which enable tumor-specific treatment. In addition to Ewing's sarcoma, which occurs as bone as well as extra-skeletal soft tissue tumors as asmall round cell sarcoma, three other subtypes of undifferentiated, small and round cell sarcomas have been introduced. Some names of the new sarcomas can be derived from the gene mutations. The groups of adipocytic and (myo)fibroblastic tumors have been extended by three further entities. There were further additions to vascular soft tissue tumors, smooth muscle cell tumors, peripheral nerve sheath tumors and tumors of uncertain differentiation. Adistinction is made between benign, intermediate locally aggressive, intermediate rarely metastatic and malignant soft tissue tumors.

Mesenchymal chondrosarcoma (MCS) is a rare and highly aggressive tumour of soft tissue and bone that is defined by an underlying and highly specific fusion transcript involving HEY1 and NCOA2. Histologically, the tumours show a biphasic appearance consisting of an undifferentiated blue and round cell component as well as islands of highly differentiated cartilage. Particularly in core needle biopsies, the chondromatous component can be missed and the non-specific morphology and immunophenotype of the round cell component can cause diagnostic challenges. We applied NKX3.1 immunohistochemistry which was recently reported as a highly specific marker as well as methylome and copy number profiling to a set of 45 well characterised MCS cases to evaluate their potential diagnostic value. Methylome profiling revealed a highly distinct cluster for MCS. Notably, the findings were reproducible also when analysing the round cell and cartilaginous component separately. Furthermore, four outliers were identified by methylome profiling for which the diagnosis had to be revised. NKX3.1 immunohistochemistry showed positivity in 36% of tumours, the majority of which was rather focal and weak. Taken together, NKX3.1 expression showed a low sensitivity but a high specificity in our analysis. Methylome profiling on the other hand represents a sensitive, specific and reliable tool to support the diagnosis of MCS, particularly if only the round cell component is obtained in a biopsy and the diagnosis is not suspected. Furthermore, it can aid in confirming the diagnosis in case RNA sequencing for the HEY1::NCOA2 fusion transcript is not available.

The Journal of Bone and Joint Surgery. British volumeVol. 89-B, No. 7 Book ReviewsFree AccessImaging of soft tissue tumors (second edition) Edited by M. J. Kransdorf and M. D. Murphey Pp 588. Philadelphia: Lippincott, Williams & Wilkins, 2006, ISBN: 0-7817-4771-6. $199.00.Alistair RossAlistair RossSearch for more papers by this authorPublished Online:1 Jul 2007https://doi.org/10.1302/0301-620X.89B7.0890991bAboutSectionsPDF/EPUB ToolsDownload CitationsTrack CitationsPermissionsAdd to Favourites ShareShare onFacebookTwitterLinked InRedditEmail When a surgeon sits down to review a book that is primarily aimed at radiologists, it has to be a remarkable volume that will retain his interest throughout and be praised unreservedly at its conclusion.This book is the result of a monumental effort to classify and describe more than 30 000 soft-tissue tumours seen in the Department of Soft Tissue Pathology of the US Armed Forces Institute of Pathology over a 10-year period. These are documented in detail in Chapter 2 with their prevalence by age, sex and anatomical location. This follows a preliminary chapter on the origin and classification of soft-tissue tumours which introduces the WHO classification before giving a brief account of the immunohistochemical and genetic markers used in diagnosis. Chapter 3 is modestly titled “Imaging of Soft Tissue Tumours”; essentially it covers the whole process of tumour staging. There then follow chapters on the imaging of the various types of soft-tissue tumour and tumour-like lesions and a final chapter on compartmental anatomy.So far, so good, but it gets better. In each section, the key concepts are abstracted and boxed. Consequently, within the main body of the text there is, in effect, a second book which comprises short notes on the first. This considerably enhances its value as a reference book by making the relevant information rapidly accessible. Indeed, I can barely remember the last tme I read a medical book which was so clearly written and so devoid of waffle.Invevitably, a book on imaging stands or falls on the quality of its images. While there are a few illustrations which fall below a desirable standard, these are usually examples of the rarer conditions where the authors will only have had access to one or two cases. In a work of this breadth, this is not only inevitable but eminently forgivable. Otherwise, the figures are clear and well annotated. The work, as a whole, is well-referenced, well-indexed and well-produced.I enjoyed this book immensely. In their preface, the authors declae their intent to “provide a systematic approach to the radiologic evaluation and diagnosis of soft tissue tumors and tumor-like masses.” Not only have they achieved this, but they have done so with rigour and clarity. Any surgeon with an interest in soft-tissue tumours should have a copy of this book in his personal library next to Enzinger and Weiss which it complements perfectly. Others, without any interest in soft-tissue tumours, could read it with benefit as a model of how to communicate a large amount of detailed information with style, brevity and pellucid clarity.FiguresReferencesRelatedDetails Vol. 89-B, No. 7 Metrics Downloaded 123 times History Published online 1 July 2007 Published in print 1 July 2007 InformationCopyright © 2007, The British Editorial Society of Bone and Joint Surgery: All rights reservedPDF download

Introduction: Soft tissue tumors are heterogenous group of tumors with diverse histology and similar clinical and radiological features. Benign soft tissue tumors outnumber sarcomas by a wide margin. Aim and Objectives: To perform category-wise analysis of benign soft tissue tumors and correlate histopathological distribution with clinical parameters. Materials and Methods: This was a retrospective type of study carried out over a period of four and half years. Histopathological examination of all the excisional biopsies of benign soft tissue tumors was performed. The tumors were classified as per WHO classification of soft tissue tumors 2013. The data was represented in the form of frequency and percentage. Analysis of histopathological findings was performed followed by correlation of histopathological findings with clinical parameters. Results: A total of 256 benign soft tissue tumors were studied. These tumors were most commonly seen in fourth decade of life and were more common in males with male to female ratio of 1.15: 1. Trunk was the most common site followed by upper extremity. Adipocytic tumors (215 cases, 84%) were most common among all the tumors, followed by nerve sheath tumors (27 cases 10.5%) and vascular tumors (12 cases 4.7%). There was one case each of benign fibrous histiocytoma and glomus tumor. Conclusion: Adipocytic tumors form the bulk of benign soft tissue tumors. But there is a considerable variety among the remaining small proportion of these tumors. Most of these have peculiarities regarding the age, gender and site-wise distribution.

Rheumatoid arthritis (RA)-related lesions, including synovitis and rheumatoid nodules, may mimic musculoskeletal tumors and cause diagnostic uncertainty. This study aimed to characterize clinical features that distinguish true tumors from tumor-like lesions in RA patients referred for suspected bone or soft tissue tumors. We retrospectively reviewed 70 RA patients evaluated between September 2009 and February 2025 for suspected musculoskeletal tumors. Patients were categorized as (1) newly diagnosed RA with tumor-like lesions (n=27), (2) established RA with tumor-like lesions (n=20), and (3) established RA with true tumors (n=23). Clinical characteristics, MRI findings, and histologic results were assessed. Logistic regression was used to identify factors associated with tumor diagnosis. Patients with true tumors were older (median 69 vs. 55y, p<0.01) and more likely to have extra-articular lesions (96% vs. 28%, p<0.01). Synovitis-like MRI patterns-low-to-intermediate T1 and heterogeneous high T2 signals-were seen in 83% of tumor-like lesions but in only 43% of true tumors. Histologic confirmation was performed in 56% of all cases (74% of tumors vs. 47% of tumor-like lesions, p=0.03). Multivariate analysis suggested that older age (OR: 1.13, 95% CI: 1.04-1.23) and extra-articular location (OR: 434.86, 95% CI: 9.44-20,035.22) were associated with tumor diagnosis. Among RA patients evaluated for suspected musculoskeletal tumors, older age and extra-articular lesion location were associated with true tumor diagnosis, although the estimates showed wide confidence intervals. MRI features alone were insufficient for reliable differentiation, underscoring the continued need for histologic confirmation to ensure accurate and timely diagnosis.