Soft tissue sarcomas at a glance: clinical, histological, and MR imaging features of malignant extremity soft tissue tumors

T1 relaxation: Chemo-physical fundamentals of magnetic resonance imaging and clinical applications

A knowledge of the complex phenomena that regulate T1 signal on Magnetic Resonance Imaging is essential in clinical practice for a more effective characterization of pathological processes. The authors review the physical basis of T1 Relaxation Time and the fundamental aspects of physics and chemistry that can influence this parameter. The main substances (water, fat, macromolecules, methemoglobin, melanin, Gadolinium, calcium) that influence T1 and the different MRI acquisition techniques that can be applied to enhance their presence in diagnostic images are then evaluated. An extensive case illustration of the different phenomena and techniques in the areas of CNS, abdomino-pelvic, and osteoarticular pathology is also proposed. CRITICAL RELEVANCE STATEMENT: T1 relaxation time is strongly influenced by numerous factors related to tissue characteristics and the presence in the context of the lesions of some specific substances. An examination of these phenomena with extensive MRI exemplification is reported. KEY POINTS: The purpose of the paper is to illustrate the chemical-physical basis of T1 Relaxation Time. MRI methods in accordance with the various clinical indications are listed. Several examples of clinical application in abdominopelvic and CNS pathology are reported.

Progressive Improvement in 5-Year Survival Rates for Extremity Soft Tissue Sarcomas from 1999 to 2019

Background

Extremity soft-tissue sarcoma (ESTS) is a group of rare, heterogeneous malignancies. Previous studies have demonstrated a progressive improvement in 5-year survival rate over time, but recent trends are unknown. Therefore, this study aimed to provide an update on the clinical characteristics and 5-year survival rate of ESTS from 1999 to 2019.

Methods

This retrospective cohort study used the Surveillance, Epidemiology, and End Results (SEER) database. Overall, 5,654 patients over the age of 15 years with primary ESTS diagnosed between 1999 and 2019 were included. Data on patient demographics, clinical characteristics, and survival were extracted. Patients were grouped by year of diagnosis: 1999-2005, 2006-2012, and 2013-2019. Kaplan-Meier and Cox proportional hazards regression analyses were performed.

Results

ESTS occurred primarily in the lower extremity (76.1%) and was frequently grade III (58.3%), >5 cm in size (69.9%), and without metastasis (77.9%) at diagnosis. Furthermore, there was a significant increase in the proportion of patients over age 60 (p < 0.001) and without metastasis (p < 0.001) over the study period. The 5-year survival rate successively improved, from 47% in 1999-2005, to 61% in 2006-2012, to 78% in 2013-2019. Similarly, in multivariate analysis, the mortality rate progressively declined from a hazard ratio (HR) of 3.4 in 1999-2005 to an HR of 2.1 in 2006-2012, with the 2013-2019 group having the best overall survival (p < 0.001). Age, tumor size, grade, and metastasis were negative prognostic factors for survival; radiation and surgery were positive prognostic factors.

Conclusions

The 5-year overall survival rate for ESTS progressively improved over the 20-year study period, perhaps due to an increasing proportion of older patients diagnosed with local disease. These findings may also be related to earlier detection or more effective treatment over the study period.

Resect, rewire, and restore: Nerve transfer salvage of neurological deficits associated with soft tissue tumors in a retrospective cohort series at a tertiary reconstructive center

AIMS

We aimed to explore the effectiveness of nerve transfer as an intervention to restore neurological deficits caused by extremity tumors through direct nerve involvement, neural compression, or as a consequence of oncological surgery.

METHODS

A retrospective cohort study of consecutive cases was conducted, including all patients who underwent nerve transfers to restore functional deficits in limbs following soft tissue tumor resection. The threshold for a successful nerve transfer was a BMRC motor grade of 4/5 and sensory grade of 3-3+/4 with protective sensation.

RESULTS

In total, 29 nerve transfers (25 motor and 4 sensory) were completed in 11 patients, aged 12-70 years at referral, over a 6-year period to 2020. This included 22 upper limb and 3 lower limb motor nerve transfers. The timing of delayed nerve transfer reconstructions was 1-15 months following primary oncological resection, with immediate simultaneous reconstructions performed in 4 cases. The threshold for success was achieved in 82% of upper limb and 33% of lower limb motor nerve transfers, while all sensory transfers were successful in restoring protective sensation.

CONCLUSION

Nerve transfer surgery, a well-established technique in restoring deficits following traumatic nerve injury, is further demonstrably relevant in extremity oncological reconstruction, especially as it can be performed remotely to the tumor location or resection site and introduces a healthy nerve or fascicle to rapidly reinnervate distal muscles without sacrificing major function. This study further illustrates the importance of early recognition and referral to specialist services where multi-disciplinary surgical resection and reconstructive planning can be conducted.

LEVEL OF EVIDENCE

IV Clinical Case Series.

Patient-Derived Organoids as a Promising Tool for Multimodal Management of Sarcomas

The management of sarcomas, a diverse group of cancers arising from connective tissues, presents significant challenges due to their heterogeneity and limited treatment options. Patient-derived sarcoma organoids (PDSOs) have emerged as a promising tool in the multimodal management of sarcomas, offering unprecedented opportunities for personalized medicine and improved treatment strategies. This review aims to explore the potential of PDSOs as a promising tool for multimodal management of sarcomas. We discuss the establishment and characterization of PDSOs, which realistically recapitulate the complexity and heterogeneity of the original tumor, providing a platform for genetic and molecular fidelity, histological resemblance, and functional characterization. Additionally, we discuss the applications of PDSOs in pathological and genetic evaluation, treatment screening and development, and personalized multimodal management. One significant advancement of PDSOs lies in their ability to guide personalized treatment decisions, enabling clinicians to assess the response and efficacy of different therapies in a patient-specific manner. Through continued research and development, PDSOs hold the potential to revolutionize sarcoma management and drive advancements in personalized medicine, biomarker discovery, preclinical modeling, and therapy optimization. The integration of PDSOs into clinical practice can ultimately improve patient outcomes and significantly impact the field of sarcoma treatment.

Ensemble learning-based radiomics with multi-sequence magnetic resonance imaging for benign and malignant soft tissue tumor differentiation

Many previous studies focused on differentiating between benign and malignant soft tissue tumors using radiomics model based on various magnetic resonance imaging (MRI) sequences, but it is still unclear how to set up the input radiomic features from multiple MRI sequences. Here, we evaluated two types of radiomics models generated using different feature incorporation strategies. In order to differentiate between benign and malignant soft tissue tumors (STTs), we compared the diagnostic performance of an ensemble of random forest (R) models with single-sequence MRI inputs to R models with pooled multi-sequence MRI inputs. One-hundred twenty-five STT patients with preoperative MRI were retrospectively included and consisted of training (n = 100) and test (n = 25) sets. MRI included T1-weighted (T1-WI), T2-weighted (T2-WI), contrast-enhanced (CE)-T1-WI, diffusion-weighted images (DWIs, b = 800 sec/mm2) and apparent diffusion coefficient (ADC) maps. After tumor segmentation on each sequence, 100 original radiomic features were extracted from each sequence image and divided into three-feature sets: T features from T1- and T2-WI, CE features from CE-T1-WI, and D features from DWI and ADC maps. Four radiomics models were built using Lasso and R with four combinations of three-feature sets as inputs: T features (R-T), T+CE features (R-C), T+D features (R-D), and T+CE+D features (R-A) (Type-1 model). An ensemble model was built by soft voting of five, single-sequence-based R models (Type-2 model). AUC, sensitivity, specificity, and accuracy of each model was calculated with five-fold cross validation. In Type-1 model, AUC, sensitivity, specificity, and accuracy were 0.752, 71.8%, 61.1%, and 67.2% in R-T; 0.756, 76.1%, 70.4%, and 73.6% in R-C; 0.750, 77.5%, 63.0%, and 71.2% in R-D; and 0.749, 74.6%, 61.1%, and 68.8% R-A models, respectively. AUC, sensitivity, specificity, and accuracy of Type-2 model were 0.774, 76.1%, 68.5%, and 72.8%. In conclusion, an ensemble method is beneficial to incorporate features from multi-sequence MRI and showed diagnostic robustness for differentiating malignant STTs.

Imaging Recommendations for Diagnosis, Staging, and Management of Soft Tissue Sarcomas

Soft tissue lesions are a wide range of tumors of mesenchymal cell origin, occurring anywhere in the body with a vast number of histological subtypes both benign and malignant. These are common in clinical practice and vast majority are benign. This article focuses on soft tissue sarcoma of the trunk and extremities and discusses their imaging guidelines.

Head and Neck Sarcoma Tumor Board Survival Guide for Neuroradiologists: Imaging Findings, History, and Pathology

Sarcomas of the head and neck carry a poor prognosis as diagnosis is often delayed until a late stage of the disease. Accordingly, it is essential to be familiar with the clinical and imaging features of sarcomas to suggest an appropriate differential diagnosis for collaborating surgeons and pathologists. However, as there are only 1000-1500 cases in the United States annually, many radiologists lack experience with pertinent imaging findings of sarcoma and lack knowledge of both treatment and necessary follow-up. In this review, a brief discussion of WHO definitions and histopathology is included to decode information provided by pathologists. Finally, staging and treatments are illuminated to aid the radiologist with initial imaging staging and follow-up care. This review aims to increase the comprehensive knowledge of a neuroradiologist and further their value to the multidisciplinary tumor board.

Issues of diagnostic search of soft tissue sarcoma

Relevance. Soft tissue sarcoma is a heterogeneous group of relatively rare types of tumors, which demonstrates a huge variety of anatomical localization and histopathological characteristics. The rarity of soft tissue sarcomas combined with a variety of subtypes, forms of growth, progression and frequency of relapses makes it difficult to study them, make a correct diagnosis and early referral of patients for specialized care.

The purpose of study. To analyze the problem of differential diagnosis of malignant and benign soft tissue neoplasms.

Materials and methods. In the course of the work, current literary sources of domestic and foreign authors on a given topic were analyzed.

Results. Since it is absolutely impossible to determine the clinical features of the presented sarcoma, soft tissue tumors showing any of the following signs are considered malignant until the opposite is proven: increasing in size, >5 cm, deeply located and/or painful. The greater the number of these clinical signs present, the higher the risk that the soft tissue tumor will turn out to be malignant; at the same time, an increase in size is the best individual indicator. It is worth noting that the absence of concomitant constitutional symptoms, such as fever, chills, night sweats or unintentional weight loss, should not reduce the doctor's suspicion of malignancy.

Conclusion. In order to avoid erroneous diagnoses, a standardized diagnostic approach should be followed, starting from the moment of collecting the patient's medical history, clinical examination and ending with the use of appropriate imaging methods and biopsy.

Issues of diagnostic search of soft tissue sarcoma

Relevance. Soft tissue sarcoma is a heterogeneous group of relatively rare types of tumors, which demonstrates a huge variety of anatomical localization and histopathological characteristics. The rarity of soft tissue sarcomas combined with a variety of subtypes, forms of growth, progression and frequency of relapses makes it difficult to study them, make a correct diagnosis and early referral of patients for specialized care.

The purpose of study. To analyze the problem of differential diagnosis of malignant and benign soft tissue neoplasms.

Materials and methods. In the course of the work, current literary sources of domestic and foreign authors on a given topic were analyzed.

Results. Since it is absolutely impossible to determine the clinical features of the presented sarcoma, soft tissue tumors showing any of the following signs are considered malignant until the opposite is proven: increasing in size, >5 cm, deeply located and/or painful. The greater the number of these clinical signs present, the higher the risk that the soft tissue tumor will turn out to be malignant; at the same time, an increase in size is the best individual indicator. It is worth noting that the absence of concomitant constitutional symptoms, such as fever, chills, night sweats or unintentional weight loss, should not reduce the doctor's suspicion of malignancy.

Conclusion. In order to avoid erroneous diagnoses, a standardized diagnostic approach should be followed, starting from the moment of collecting the patient's medical history, clinical examination and ending with the use of appropriate imaging methods and biopsy.

Soft Tissue Sarcomas: The Role of Quantitative MRI in Treatment Response Evaluation

BACKGROUND

Although curative surgery remains the cornerstone of the therapeutic strategy in patients with soft tissue sarcomas (STS), neoadjuvant radiotherapy and chemotherapy (NART and NACT, respectively) are increasingly used to improve operability, surgical margins and patient outcome. The best imaging modality for locoregional assessment of STS is MRI but these tumors are mostly evaluated in a qualitative manner.

OBJECTIVE

After an overview of the current standard of care regarding treatment for patients with locally advanced STS, this review aims to summarize the principles and limitations of (i) the current methods used to evaluate response to neoadjuvant treatment in clinical practice and clinical trials in STS (RECIST 1.1 and modified Choi criteria), (ii) quantitative MRI sequences (i.e., diffusion weighted imaging and dynamic contrast enhanced MRI), and (iii) texture analyses and (delta-) radiomics.

Clinical Routine and Necessary Advances in Soft Tissue Tumor Imaging Based on the ESSR Guideline: Initial Findings

Soft tissue sarcomas are malignant diseases with a complex classification and various histological subtypes, mostly clinically inconspicuous appearance, and a rare occurrence. To ensure safe patient care, the European Society of Musculoskeletal Radiology (ESSR) issued a guideline for diagnostic imaging of soft tissue tumors in adults in 2015. In this study, we investigated whether implementation of these guidelines resulted in improved MRI protocol and report quality in patients with soft tissue sarcomas in our cancer center. All cases of histologically confirmed soft tissue sarcomas that were treated at our study center from 2006 to 2018 were evaluated retrospectively. The radiological reports were examined for their compliance with the recommendations of the ESSR. Patients were divided into two groups, before and after the introduction of the 2015 ESSR guidelines. In total, 103 cases of histologically confirmed sarcomas were studied. The distribution of, age, gender, number of subjects, performing radiology, and MRI indication on both groups did not show any significant differences. Only using the required MRI sequences showed a significant improvement after the introduction of the guidelines (p = 0.048). All other criteria, especially the requirements for the report of findings, showed no improvement. The guidelines of the European Society for Musculoskeletal Radiology are not regularly followed, and their establishment did not consistently improve MRI quality in our study group. This poses a risk for incorrect or delayed diagnosis and, ultimately, therapy of soft tissue tumors. However, this study is the first of its kind and involves a limited collective. A European-wide multicenter study would be appreciated to confirm these results.

Imaging characteristics of slow-growing soft tissue chondroma of the tongue: A case report

INTRODUCTION

Extraskeletal soft tissue chondroma (STC) is a rare benign tumor. Soft-tissue chondromas rarely occur in the oral cavity. In this study, we aimed to confirm a slow-growing tongue mass using magnetic resonance imaging.

PATIENT CONCERNS

A 60-year-old woman presented with a painful, slow-growing tongue mass that had persisted for 17 years. Intraoral examination revealed a pedunculated mass covered with mucosa on the right side of her tongue.

DIAGNOSIS

CT and MRI revealed a lobulated heterogeneously enhancing mass without calcification. Compared with previous images obtained 17 years prior, the mass presented slow growth, more prominent enhancement, and lobulated contour. Histopathological examination confirmed the presence of STC.

INTERVENTIONS

Excision of the mass surrounding normal tissue was performed under general anesthesia.

OUTCOMES

During 1-year follow-up period, no recurrence was observed.

CONCLUSIONS

In this study, STC lesions were slow-growing, and changed from weakly homogeneous enhancement and clean margins to markedly heterogeneous enhancement and lobulated margins over time.

Neoadjuvant irradiation of extremity soft tissue sarcoma with ions (Extrem-ion): study protocol for a randomized phase II pilot trial

BACKGROUND

The standard of care treatment for soft tissue sarcoma of the extremities is a wide resection in combination with pre- or postoperative radiotherapy with high local control rates, sparing patients the necessity of amputation without compromising on overall survival rates. The currently preferred timing of radiotherapy is under debate. Albeit having higher rates of acute wound complications, late side effects like fibrosis, joint stiffness or edema are less frequent in preoperative compared to postoperative radiotherapy. This can be explained in smaller treatment volumes and a lower dose in the preoperative setting. Particles allow better sparing of surrounding tissues at risk, and carbon ions additionally offer biologic advantages and are preferred in less radiosensitive tumors. Hypofractionation allows for a significantly shorter treatment duration.

METHODS

Extrem-ion is a prospective, randomized, monocentric phase II trial. Patients with resectable or marginally resectable, histologically confirmed soft tissue sarcoma of the extremities will be randomized between neoadjuvant proton or neoadjuvant carbon ion radiotherapy in active scanning beam application technique (39 Gy [relative biological effectiveness, RBE] in 13 fractions [5-6 fractions per week] in each arm). The primary objective is the proportion of therapies without wound healing disorder the first 120 days after surgery or discontinuation of treatment for any reason related to the treatment. The secondary endpoints of the study consist of local control, local progression-free survival, disease-free survival, overall survival, and quality of life.

DISCUSSION

The aim of this study is to confirm that hypofractionated, preoperative radiotherapy is safe and feasible. The potential for reduced toxicity by the utilization of particle therapy is the rational of this trial. A subsequent randomized phase III trial will compare the hypofractionated proton and carbon ion irradiation in regards to local control.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04946357 ; Retrospectively registered June 30, 2021.

Retrospective immunohistochemical investigation of suspected non-visceral leiomyosarcoma in dogs

Visceral leiomyosarcoma is well described in dogs, but information about non-visceral locations and prevalence is lacking. The diagnosis of leiomyosarcoma is challenging without a gold standard, and often includes the use of immunohistochemical (IHC) stains. We used defined histopathologic patterns, histochemical staining, and IHC staining for smooth muscle actin (SMA), desmin, and laminin to characterize suspected non-visceral leiomyosarcoma in dogs at a single academic institution. In a retrospective search, we identified 24 dogs with a definitive or suspected histologic diagnosis of leiomyosarcoma in a non-visceral location. Histopathology results and clinical details were obtained. Biopsy sections were reviewed by a single pathologist using standardized histologic criteria, including light microscopic appearance, immunohistochemistry (more than two-thirds of neoplastic cells labeled with SMA and desmin or laminin), and histochemical staining (minimal-to-mild matrix deposition by Masson trichrome). Of the 24 cases of possible non-visceral leiomyosarcomas, 4 were consistent with a definitive diagnosis of non-visceral leiomyosarcoma (3) or leiomyoma (1) based on the established criteria. Only the leiomyoma had more than two-thirds of neoplastic cells label with all 3 markers; all 3 leiomyosarcomas had more than two-thirds of neoplastic cells label with SMA and laminin. Our data highlight the uncommon nature of non-visceral leiomyosarcoma and the importance of IHC for their diagnosis. A definitive diagnosis could not be made based on SMA alone, and desmin was not useful in this cohort. Further studies are needed to clarify the histopathologic, IHC, and clinical features of canine non-visceral SMA-positive mesenchymal tumors.

Gemcitabine Maintenance Therapy in Patients With Metastasized Soft Tissue Sarcomas

Background

Metastasized soft-tissue sarcomas still pose a significant therapeutic challenge given the limited efficacy of currently available multimodal treatment strategies. Recent progress in molecular characterization of sarcoma subtypes has enabled successful personalized therapy approaches in a minority of selected patients with targetable mutations. However, in the majority of patients with refractory soft tissue sarcomas, long-term survival remains poor.

Methods

We report on three adult patients with various soft tissue sarcomas subjected to Gemcitabine maintenance therapy. Tumor entities included leiomyosarcoma of the pancreas (patient 1), undifferentiated pleomorphic sarcoma of the right femur (patient 2), and peri-aortic leiomyosarcoma (patient 3). Metastatic sites encompassed liver, lung, and bones. All patients received Gemcitabine maintenance therapy until disease progression following prior salvage chemotherapy with Docetaxel and Gemcitabine. Patients were treated outside of clinical trials. Response assessment was based on radiological imaging.

Results

In response to salvage chemotherapy with Docetaxel and Gemcitabine, one patient exhibited a partial remission, and two patients showed stable disease. Patient 1 exhibited stable disease for 6 months during Gemcitabine maintenance therapy before suffering rapid progression of hepatic metastases. Patient 2 underwent 21 months of Gemcitabine maintenance therapy, which was discontinued after progressive pulmonary metastases were detected. Patient 3 is still being treated with Gemcitabine maintenance therapy. Remarkably, owing to significant chemotherapy-associated hematotoxicity, the dose of Gemcitabine dose was reduced by two-thirds. Nevertheless, stable disease with constant pulmonary metastases has been maintained in this patient for 14 months.

Conclusions

Gemcitabine maintenance therapy following prior Docetaxel and Gemcitabine chemotherapy is manageable and reveals potential benefits for patients with aggressive metastasized soft tissue sarcomas. Prospective trials evaluating Gemcitabine maintenance therapy are encouraged.

Overview of malignant soft-tissue sarcomas of the limbs

Although soft-tissue masses are common, sarcomas are rare malignant neoplasms showing variable mesenchymal differentiation and can occur at any anatomical site. Limb soft-tissue sarcomas (STS) are rare, but often lethal tumours. Although there are scores of historical pathological subtypes, this article will deal with the commonest: liposarcoma, leiomyosarcoma (LMS), undifferentiated pleomorphic sarcoma (UPS), synovial sarcoma, myxofibrosarcoma, malignant peripheral nerve sheath tumour (MPNST), epithelioid sarcoma, alveolar rhabdosarcoma, angiosarcoma and radiation-induced sarcoma (RIS). Following a review of >4,000 adult patients with limb sarcoma from our specialist soft-tissue tumour database, we summarise the literature and their imaging findings, with emphasis on radiological hallmarks that can aide in diagnosis and management. Increased awareness of sarcoma when challenged with a new mass in the extremity can ensure timely and appropriate treatment.

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

The WHO classification of soft tissue tumours categorizes the lesions based on histological differentiation. In the recent fifth edition (2020), many new entities have been introduced, based on their distinct biological behaviour, genetics and morphology. With the recent advances and better understanding of molecular genetics, several novel recurrent genetic alterations have been incorporated in this edition. These may serve as reliable diagnostic and prognostic markers for various soft tissue tumours. Though predominantly a pathologist's game; the radiologists must be aware of the recent updates to contribute towards the optimal diagnosis and management of soft tissue tumours. The imaging features of the new entities have not yet been described but are expected to be explored in the coming years. We hereby present a concise review of the updates in the recent WHO classification of soft tissue tumours. We have tried to emphasize the novel molecular genetics and their surrogate immunohistochemical markers which have brought a paradigm shift in the diagnosis, therapeutics, and prognosis of soft tissue tumours. We also present simplified diagnostic algorithms to characterize soft tissue tumours based on the clinico-radiological features.

Post-traumatic myositis ossificans: a benign lesion that simulates malignant bone and soft tissue tumours

Myositis ossificans (MO) is a benign bone formation in an extra-skeletal location. The most common subtype of MO, the post-traumatic, usually develops in young males after a traumatic event or sports injury.MO may simulate malignant bone lesions such as extra-skeletal or surface osteosarcomas, or soft tissue sarcomas such as synovial sarcoma or undifferentiated pleomorphic sarcoma. In the early phase the diagnosis of MO is challenging because imaging and histopathological findings may be non-characteristic.Detailed medical history as well as clinical examination, follow-up imaging studies and histological assessment are crucial for a proper diagnosis. Early and accurate differential diagnosis between MO and malignant soft tissue and bone tumours is important to maximize. Cite this article: EFORT Open Rev 2021;6:572-583. DOI: 10.1302/2058-5241.6.210002.

GEIS-SEHOP clinical practice guidelines for the treatment of rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is the most frequent soft tissue sarcoma (STS) in children and adolescents. In Spain the annual incidence is 4.4 cases per million children < 14 years. It is an uncommon neoplasm in adults, but 40% of RMS are diagnosed in patients over 20 years of age, representing 1% of all STS in this age group. RMS can appear anywhere in the body, with some sites more frequently affected including head and neck, genitourinary system and limbs. Assessment of a patient with suspicion of RMS includes imaging studies (MRI, CT, PET-CT) and biopsy. All patients with RMS should receive chemotherapy, either at diagnosis in advanced or metastatic stages, or after initial resection in early local stages. Local control includes surgery and/or radiotherapy depending on site, stage, histology and response to chemotherapy. This guide provides recommendations for diagnosis, staging and treatment of this neoplasm.

Relationship Between Ultrasound Features and Ki-67 Labeling Index of Soft Tissue Sarcoma

Objectives

To explore the relationship between ultrasound (US) features and Ki-67 labeling index (LI) of soft tissue sarcoma (STS).

Methods

Forty-six patients with 47 STS lesions, between September 2014 and April 2020, were enrolled in the study. Point-biserial correlation analysis and Spearman’s correlation analysis were utilized to examining the relationship between the US features and the Ki-67 LI of STS. The differences of US features between high and low Ki-67 proliferation groups were statistically analyzed by independent t test, Wilcoxon rank-sum test, and Fisher’s exact test. The optimal cut-off points of US features revealing significant differences were estimated by the maximum Youden index.

Results

A moderate correlation between the vascular density grade and the Ki-67 LI (ρ = 0.409, P = 0.004) was found in this study. In addition, other ultrasound features were irrelevant to the Ki-67 LI. The cut-off for differentiating low- and high-proliferation groups was grade II according to the best Youden index. The area under receiver operating characteristic (ROC) curve was 0.74 (p = 0.011) with a sensitivity of 60.6% and specificity of 78.6%.

Conclusions

Only the vascular density grade of STS had a weak positive correlation with Ki-67 LI, and might be capable of predicting the proliferation of STS. Other ultrasonographic features of STS such as shape and tumor margin have no correlation with Ki-67 LI.

Efficacy and Cost-Benefit Analysis of Magnetic Resonance Imaging in the Follow-Up of Soft Tissue Sarcomas of the Extremities and Trunk

There is no consensus regarding follow-up after soft tissue sarcoma (STS) treatment. This study examines the efficacy and the cost-benefit of MRI imaging for discovering recurrence. A retrospective analysis was performed, collecting data on patient demography, tumor characteristics, treatment, and follow-up. Imaging was correlated to the clinical course, and sensitivity, specificity, and predictive values were calculated. The number needed to screen and costs of finding recurrence are reported. Amongst 216 sarcomas, 73 (35%) exhibited local recurrence during a follow-up of 5.3 ± 3.5 years. 173 entities had complete MRI follow-up with 58 (34%) local recurrences. Thirty-three (57%) were discovered by MRI, 8 (14%) by clinical presentation, and 17 (29%) simultaneously. There was a sensitivity of 100.00%, a specificity of 89%, a positive predictive value of 32%, and a negative predictive value of 100% for detecting local recurrence with MRI. Our data confirm the modalities and intervals proposed by the German guidelines for sarcoma care. The recommended MRI intervals should not be extended. MRI is more cost-effective than clinical examination; still, both modalities should be performed together to discover the maximum number of recurrences.

Imaging of Soft Tissue Tumors

Differentiation of malignant from benign soft tissue tumors is challenging with imaging alone, including that by magnetic resonance imaging and computed tomography. However, the accuracy of this differentiation has increased owing to the development of novel imaging technology. Detailed patient history and physical examination remain essential for differentiation between benign and malignant soft tissue tumors. Moreover, measurement only of tumor size based on Response Evaluation Criteria In Solid Tumors criteria is insufficient for the evaluation of response to chemotherapy or radiotherapy. Change in metabolic activity measured by ¹⁸F-fluorodeoxyglucose positron emission tomography or dynamic contrast enhanced-derived quantitative endpoints can more accurately evaluate treatment response compared to change in tumor size. Magnetic resonance imaging can accurately evaluate essential factors in surgical planning such as vascular or bone invasion and "tail sign". Thus, imaging plays a critical role in the diagnosis and treatment of soft tissue tumors.

Soft tissue masses: distribution of entities and rate of malignancy in small lesions

BACKGROUND

Small soft tissue masses are often falsely assumed to be benign and resected with failure to achieve tumor-free margins. Therefore, this study retrospectively investigated the distribution of histopathologic diagnosis to be encountered in small soft tissue tumors (≤ 5 cm) in a large series of a tertiary referral center.

METHODS

Patients with a soft tissue mass (STM) with a maximum diameter of 5 cm presenting at our institution over a period of 10 years, who had undergone preoperative Magnetic resonance imaging and consequent biopsy or/and surgical resection, were included in this study. A final histopathological diagnosis was available in all cases. The maximum tumor diameter was determined on MR images by one radiologist. Moreover, tumor localization (head/neck, trunk, upper extremity, lower extremity, hand, foot) and depth (superficial / deep to fascia) were assessed.

RESULTS

In total, histopathologic results and MR images of 1753 patients were reviewed. Eight hundred seventy patients (49.63%) showed a STM ≤ 5 cm and were therefore included in this study (46.79 +/- 18.08 years, 464 women). Mean maximum diameter of the assessed STMs was 2.88 cm. Of 870 analyzed lesions ≤ 5 cm, 170 (19.54%) were classified as superficial and 700 (80.46%) as deep. The malignancy rate of all lesions ≤ 5 cm was at 22.41% (superficial: 23.53% / deep: 22.14%). The malignancy rate dropped to 16.49% (20.79% / 15.32%) when assessing lesions ≤ 3 cm (p = 0.007) and to 15.0% (18.18% / 13.79%) when assessing lesions ≤ 2 cm (p = 0.006). Overall, lipoma was the most common benign lesion of superficial STMs (29.41%) and tenosynovial giant cell tumor was the most common benign lesion of deep STMs (23.29%). Undifferentiated pleomorphic sarcoma was the most common malignant diagnosis among both, superficial (5.29%) and deep (3.57%) STMs.

CONCLUSIONS

The rate of malignancy decreased significantly with tumor size in both, superficial and deep STMs. The distribution of entities was different between superficial and deep STMs, yet there was no significant difference found in the malignancy rate.

Soft tissue pathology for the radiologist: a tumor board primer with 2020 WHO classification update

Radiologists serve an important role in the diagnosis and staging of soft tissue tumors, often through participation in multidisciplinary tumor board teams. While an important function of the radiologist is to review pertinent imaging and assist in the differential diagnosis, a critical role is to ensure that there is concordance between the imaging and the pathologic diagnosis. This requires a basic understanding of the pathology of soft tissue tumors, particularly in the case of diagnostic dilemmas or incongruent imaging and histologic features. This work is intended to provide an overview of soft tissue pathology for the radiologist to optimize participation in multidisciplinary orthopedic oncology tumor boards, allowing for contribution to management decisions with expertise beyond image interpretation.

Use of contrast ultrasound in differentiating thrombosed pseudoaneurysm from sarcoma, prior to surgery

We describe a case of a 69-year-old male with a right-sided popliteal mass following a motor vehicle accident 15 years ago. The mass was indeterminate via multiple modalities (magnetic resonance imaging, digital subtraction angiography, and vascular ultrasound) with biopsy requested prior to surgical removal to determine the appropriate surgical team – vascular versus sarcoma oncologic surgery. Contrast ultrasound was utilized to determine if biopsy was indicated and if so, to determine the most appropriate target. Contrast ultrasound showed no areas of enhancement, therefore biopsy was not performed and the patient safely proceeded to vascular surgery. Pathology confirmed the mass to be a thrombosed pseudoaneurysm of the popliteal artery. We present the benefits of using contrast ultrasound in the work up and diagnosis of a popliteal neoplasm versus suspected vascular complication.

MRI of Rhabdomyosarcoma and Other Soft-Tissue Sarcomas in Children

Soft-tissue sarcomas in children comprise a heterogeneous group of entities with variable manifestation depending on the age of the patient and the location of the tumor. MRI is the modality of choice for evaluating musculoskeletal soft-tissue tumors and plays a paramount role in both initial diagnosis and assessment of tumor response during and after treatment. Conventional MRI sequences, such as T1- and T2-weighted imaging, offer morphologic information, which is important for localizing the lesion and describing anatomic relationships but not accurate for determining its malignant or benign nature and may be limited in differentiating tumor response from therapy-related changes. Advanced multiparametric MRI offers further functional information that can help with these tasks by using different imaging sequences and biomarkers. The authors present the role of MRI in rhabdomyosarcoma and other soft-tissue sarcomas in children, emphasizing a multiparametric approach with focus on the utility and potential added value of diffusion-weighted imaging (DWI) and dynamic contrast-enhanced MRI in characterization and staging, determination of pretreatment extent, and evaluation of tumor response and recurrence after treatment. ^©RSNA, 2020.

Soft Tissue Special Issue: Imaging of Bone and Soft Tissue Sarcomas in the Head and Neck

Bone and soft tissue sarcomas of the head and neck are a heterogenous group of tumors with overlapping features. Distinguishing between the various subtypes is challenging but necessary for appropriate diagnosis and management. The purpose of this article is to discuss the role of imaging in evaluating head and neck tumors, provide a general radiographic approach in differentiating between benign versus malignant lesions and give examples of selected subtypes of bone and soft tissue sarcomas in the head and neck with classic or pathognomonic imaging findings.

Arm malignant peripheral nerve sheath tumour: a rare clinical presentation

Soft tissue sarcomas account for about 1% of malignant tumours. More than 50 subtypes of these tumours have been described with some being extremely rare, namely malignant peripheral nerve sheath tumours (MPNST). The authors present a case of a man aged 81 years with a medical history of an adenocarcinoma of the rectum, which was referred to our clinic due to a growing painless mass on the right arm. An MRI showed a well-delimited encapsulated mass involving the long head of the biceps muscle. Biopsy findings revealed a spindle cell tumour with cytonuclear pleomorphism. The patient underwent wide tumour excision and was successfully reconstructed with a latissimus dorsi functional muscle transfer. The presence of two pulmonary nodules on CT scan staging implied a lung biopsy that showed rectum primary tumour metastases. With these additional findings, the pathology department reassessed the case and reclassified the arm tumour as an MPNST, synchronous with pulmonary adenocarcinoma metastases of the rectum.

Head and Neck Sarcomas: A Review of Clinical and Imaging Findings Based on the 2013 World Health Organization Classification

OBJECTIVE

Head and neck sarcomas are a complex, heterogeneous group of tumors that present a diagnostic challenge to radiologists because they have many overlapping imaging features. The purpose of this article is to review the imaging and clinical features and highlight distinguishing features of head and neck sarcomas.

CONCLUSION

An understanding of characteristic imaging and clinical features of head and neck sarcomas is important for the radiologist to narrow the differential diagnosis and help guide management.

Quantification of fat content in lipid-rich myxoid liposarcomas with MRI: a single-center experience with survival analysis

OBJECTIVE

To determine the fat content of myxoid liposarcomas (MLS) on MRI and to identify any association between lipid content and survival.

MATERIALS AND METHODS

The fat percentage of MLS diagnosed between January 2006 and December 2016 at a single institution was assessed by two radiologists on preoperative MR images. A Cox proportional hazard model was used to determine any association between tumor fat percentage and survival time. Tumor fat percentage was the single predictor in the model. A significance level of 0.05 was used. The Kaplan-Meier estimator was also used to provide a nonparametric estimate of the survivor function within the entire sample and within two patient subgroups consists of lipid-rich and lipid-poor tumors. Lipid-rich tumors were defined as any tumors showing more than 20% of fat on MRI. A 20% cutoff was determined arbitrarily.

RESULTS

Of the 43 cases identified through retrospective review, 8 tumors demonstrated ≥10% fat on MRI, and 4 tumors demonstrated ≥20% fat (highest fat percentage, 38%). There was no significant survival difference between patients with high tumor fat, which was defined as ≥20% fat, compared with those with little to no tumor fat.

CONCLUSION

Myxoid liposarcomas may demonstrate a higher fat content on MRI than has previously been reported in the literature. Increased tumor fat percentage in lipid-rich tumors was not found to be associated with increased risk of death. Radiologists must be aware of the existence of MLS lesions with higher fat content.

Surgical considerations when reporting MRI studies of soft tissue sarcoma of the limbs

Soft tissue sarcomas (STS) are rare tumours that require prompt diagnosis and treatment at a specialist centre. Magnetic resonance imaging (MRI) has become the modality of choice for identification, characterisation, biopsy planning and staging of soft tissue masses. MRI enables both the operating surgeon and patient to be optimally prepared prior to surgery for the likelihood of margin-negative resection and to anticipate possible sacrifice of adjacent structures and consequent loss of function. The aim of this review is to aid the radiologist in performing and reporting MRI studies of soft tissue sarcomas, with particular reference to the requirements of the surgical oncologist.

Current Concepts in Non-Gastrointestinal Stromal Tumor Soft Tissue Sarcomas: A Primer for Radiologists

Non-gastrointestinal stromal tumor (GIST) soft tissue sarcomas (STSs) are a heterogeneous group of neoplasms whose classification and management continues to evolve with better understanding of their biologic behavior. The 2013 World Health Organization (WHO) has revised their classification based on new immunohistochemical and cytogenetic data. In this article, we will provide a brief overview of the revised WHO classification of soft tissue tumors, discuss in detail the radiology and management of the two most common adult non-GIST STS, namely liposarcoma and leiomyosarcoma, and review some of the emerging histology-driven targeted therapies in non-GIST STS, focusing on the role of the radiologist.

MRI features of calcifying aponeurotic fibroma in the upper arm: a case report and review of the literature

Calcifying aponeurotic fibroma is a rare soft tissue tumor that occurs in the distal extremities of children and adolescents. We report a case of pathologically proven calcifying aponeurotic fibroma in the left upper arm of a 23-year-old female. Radiographs revealed increased soft tissue density with multiple stippled calcifications in the mid-portion of the patient's left upper arm. Magnetic resonance imaging (MRI) showed a well-defined soft tissue mass with low to intermediate signal intensity on T1-weighted images, heterogeneously low signal intensity on T2-weighted images, and heterogeneous enhancement on fat-suppressed, contrast-enhanced T1-weighted images. Histologically, spindle cell proliferation with scattered calcifications and hyalinization was present. Seven years after surgery, there was no evidence of local recurrence. This is the first report of MRI findings of calcifying aponeurotic fibroma in the upper arm. We also summarize the MRI findings of 16 previously reported cases of calcifying aponeurotic fibroma originating in the upper or lower extremities.

Translational research in diagnosis and management of soft tissue tumours

Finding a soft tissue mass in the superficial regions is a common event in daily clinical practice. Correct management of the diagnostic process is crucial to avoid blunders. Diagnosis is posed by pathology, although both imaging and a better understanding of the cellular and molecular mechanisms play an important a role in the characterization, staging and follow-up of soft tissue masses. Cellular and molecular mechanisms can explain either the development of chemo-resistance and the underlying pre- and post-surgery metastasis formation. These are mandatory to improve prognosis and unveil novel parameters predicting therapeutic response. Imaging mainly involves ultrasound and MR and is fundamental not only in diagnosis but also in the first step of therapy: the biopsy. Novel imaging techniques like Ultrasound Elastosonography, Dynamic Contrast-Enhanced MR imaging (DCE), Diffusion Weighted MR imaging (DWI) and MR Spectroscopy (MRS) are discussed. This paper aims at reviewing and discussing pathological methods and imaging in the diagnosis of soft tissue masses underscoring that the most appropriate treatment depends on advanced molecular and radiological studies.

Clinical presentation and CT/MRI findings of alveolar soft part sarcoma: a retrospective single-center analysis of 14 cases

BACKGROUND

Alveolar soft part sarcoma (ASPS) is a relatively rare malignant tumor and early diagnosis and appropriate treatment for ASPS are essential for a good prognosis.

PURPOSE

To retrospectively review the clinical presentation and computed tomography (CT) and magnetic resonance imaging (MRI) findings of ASPS so as to improve the accuracy of imaging diagnosis.

MATERIAL AND METHODS

Fourteen patients with pathologically proven ASPS were enrolled. Their clinical and imaging findings were retrospectively reviewed.

RESULTS

The median age of the patients was 29 years (range, 13-37 years). Most tumors were located in the soft tissues of the trunk and lower limbs. The median maximal diameter of the masses was 91 mm. Thirteen masses presented with ovoid or irregular shapes. Eleven masses had less clear boundaries. Compared with the adjacent muscles, the masses were isodense or hypodense on CT, hypo-, iso-, or hyperintense on T1-weighted images, and heterogeneous hyperintense on T2-weighted images. Intense enhancement was seen after contrast agent administration, with prominent intra- or peri-tumoral feeders on CT or flow voids on MRI. By the end of the last follow-up, 13 patients had distant metastasis and three patients had local recurrence.

CONCLUSION

ASPS should be included in the differential diagnosis when a bulky, heterogeneous soft tissue mass in the trunk and the lower limbs with intense enhancement after contrast administration and prominent intra- or peri-tumoral feeders on CT or flow voids on MRI is seen, particularly in young patients.

Magnetic resonance imaging and computed tomography features of alveolar soft-part sarcoma in the right deltoid muscle: A case report

Alveolar soft-part sarcoma (ASPS) is a rare, highly vascular malignant soft-tissue tumor that predominantly affects young adults. The tumor can occur in any bodily region, but is most frequently observed in the lower deep soft tissues of the extremities, and is rarely observed in the upper extremities. The present study reported a case of ASPS of the right deltoid muscle. The patient presented with a 3-year history of a mass on the right shoulder that exhibited rapid growth in the month prior to diagnosis. Computed tomography (CT) and magnetic resonance imaging (MRI) were performed. The lesion mainly demonstrated isointense or mildly hyperintense signals compared with the muscle on the T1-weighted images of the MRI, and heterogeneous high signal intensity on the T2-weighted images. CT enhancement showed a homogeneous enhanced mass. The tumor was resected and submitted for histopathological examination. The diagnosis was verified as ASPS by microscopic examination and immunohistochemical analysis. No distant metastases were noted. No evidence of local tumor recurrence was seen at 6 weeks following the wide surgical excision. The CT scan revealed no metastatic nodules in either lung during the follow-up. ASPS should be considered as a possible diagnosis when a slow-growing, large mass is detected in young adults in the soft tissue of the extremities, with high signal intensity and numerous signal voids on T1-weighted images (T1WI) and T2WI, and strong contrast-enhancement.

Myxoid soft-tissue neoplasms: comprehensive update of the taxonomy and MRI features

OBJECTIVE. The purpose of this article is to review the classification, clinical presentation, and histopathologic and MRI features of myxoid soft-tissue neoplasms. CONCLUSION. MRI is the modality of choice for characterization of myxoid soft-tissue tumors. A combination of imaging features (including certain characteristic signs), clinical features, and patient demographics can help the radiologist in coming to a specific diagnosis or in narrowing down the differential diagnoses.

Imaging of extremity soft tissue masses: pitfalls in diagnosis

Soft tissue sarcomas are rare tumours which can be clinically difficult to differentiate from more common benign lesions. Imaging plays a fundamental role in diagnosis, but in some cases it can be difficult to differentiate benign from malignant conditions. This article reviews potential pitfalls in soft tissue sarcoma imaging.

High Grade Leiomyosarcoma Mimicking a Recurrent Angiomyxoma in the Perineum

Perineal leiomyosarcoma is an extremely rare and aggressive cancer with a high metastatic potential and no defined standard treatment. There are only a few (six) reported cases in the literature. We report the case of a 67-year-old woman with a perineal leiomyosarcoma arising at the same site of a previously resected superficial angiomyxoma. Initially, she was treated for a presumptive recurrence of angiomyxoma. As she did not respond to medical therapy, she underwent repeat surgical excision. Pathology revealed a high grade leiomyosarcoma, histologically strikingly distinct from the initial diagnosis. She received adjuvant local radiation therapy, and remains without evidence of recurrent disease 36 months after completion of all therapy. This is the first reported case of a high grade perineal leiomyosarcoma originating at the same site as a resected benign superficial angiomyxoma. Our case emphasizes the necessity of a prompt histological diagnosis in cases of presumed recurrent perineal angiomyxoma.

Well-differentiated liposarcoma arising in the parapharyngeal space: a case report and review of the literature

BACKGROUND

Liposarcomas rarely occur in the parapharyngeal space and only a few case reports exist. For curative therapy of liposarcoma, surgical excision remains the dominant modality. Although a wide surgical margin is important to prevent local recurrence, wide excision is often difficult in the head and neck region.

CASE REPORT

We report a case of a 19-year-old female with a well-differentiated liposarcoma arising in the parapharyngeal space. We removed the tumour surgically utilising a cervical-parotid approach. The histological diagnosis was well-differentiated sclerosing liposarcoma. There is no recurrence after five years and nine months of follow up.

CONCLUSION

The patient's age and the tumour site made it difficult for us to make a quantitative diagnosis before the operation. Well-differentiated liposarcoma rarely develop distant metastasis, but often recur locally. The benefit of adjuvant radiotherapy for well-differentiated liposarcoma is still not clear and careful and long-term follow up is necessary.

Giant subcutaneous leiomyosarcoma of anterior abdominal wall

Subcutaneous leiomyosarcomas are rare tumors accounting for 1% to 2% of all superficial soft tissue malignancies. Although they may arise anywhere in the body, they most frequently occur in the lower extremities. The incidence of subcutaneous LMS affecting the anterior abdominal wall is very rare. We herein report the case of a patient with a giant subcutaneous leiomyosarcoma arising in the anterior abdominal wall. It was diagnosed by histopathology and immunohistochemistry and treated accordingly.

Differentiation of myxoid liposarcoma by magnetic resonance imaging: a histopathologic correlation

BACKGROUND

Myxoid liposarcomas represent a heterogeneous group of soft tissue tumors in which prognosis is dependent on differentiation.

PURPOSE

To identify magnetic resonance imaging (MRI) criteria to distinguish low-grade from high-grade myxoid liposarcomas.

MATERIAL AND METHODS

MR images of 30 histologically proven myxoid liposarcomas were retrospectively reviewed. Tumors were evaluated according to size, localization, tumor border, and structure as well as tumor composition. These imaging criteria were correlated with histopathological findings.

RESULTS

Nineteen myxoid liposarcomas were histologically classified as low-grade myxoid liposarcomas, whereas 11 were considered high-grade myxoid liposarcomas. Mean tumor volume of low-grade myxoid liposarcomas (710.1 ± 960.1 ccm) was significantly smaller as compared to high-grade myxoid liposarcomas (2737.0 ± 3423.7 ccm; P = 0.04). In addition to necrotic areas, three tumor components - fatty, myxoid, as well as contrast-enhancing non-fatty, non-myxoid - could be identified. The mean fraction of fatty tumor areas in low-grade myxoid liposarcomas was 10 ± 11% as compared to 6 ± 4% for high-grade myxoid liposarcomas (P = 0.66). Myxoid components accounted for 88 ± 16% in low-grade myxoid liposarcomas, but only for 45 ± 25% in high-grade myxoid liposarcomas (P < 0.0001). The non-fatty, non-myxoid tumor fraction was significantly higher in high-grade myxoid liposarcomas (50 ± 25%) as compared to low-grade myxoid liposarcomas (2 ± 9%; P < 0.0001). A proportion of > 5% of this tumor fraction was found to be a precise unique predictor for high-grade myxoid liposarcomas with a sensitivity of 100% and a specificity of 95%.

CONCLUSION

Tumor components with contrast-enhancing non-fatty, non-myxoid imaging features were predominantly found in high-grade myxoid liposarcomas, which may histologically resemble round cell clusters.

Giant perineal leiomyoma: a case report and review of the literature

We report the case of a 40-year-old woman who presented with a large perineal mass with no rectal or vaginal involvement. Imaging could not rule out malignancy. She underwent wide surgical excision. Histological analysis revealed a large atypical leiomyoma, measuring 24 × 12 × 8 cm. Followup after two years showed no recurrence and she has been asymptomatic since surgery. This is the largest perineal leiomyoma reported so far.

Magnetic resonance imaging features of alveolar soft part sarcoma: report of 14 cases

Background

The purpose of this study was to assess the magnetic resonance imaging findings of alveolar soft part sarcoma.

Methods

Magnetic resonance images of pathologically proven alveolar soft part sarcoma in 14 patients were retrospectively reviewed, including lesion location, size and shape, border definition, signals on T1-weighted and T2-weighted images, presence or absence of peritumoral and intratumoral flow voids, and enhancement pattern.

Results

Patients included five women and nine men, ranging in age from 27 to 54 years, with a mean age of 36 years. A slow-growing mass without pain was the chief complaint. Eight patients had pulmonary metastases at presentation. Ten lesions arose from the extremities, two were located in the gluteal regions, one affected the presacral space and one occurred in the back. The mean maximal size of the lesions was 9.8 cm, ranging from 6.2 to 16 cm. All lesions appeared as a round (n = 2), ovoid (n = 8) or irregular (n = 4) shape with ill-defined margins. The lesions mainly demonstrated isointense or mildly hyperintense compared to muscle on T1-weighted images, and heterogeneous high signal intensity on T2-weighted images. Peritumoral edemas were observed in six patients. Ten lesions showed intense inhomogeneous enhancement after contrast. Intra- and peritumoral tubular flow voids representing tortuous dilated vessels with rapid blood flow were present in all cases.

Conclusions

Alveolar soft part sarcoma has some distinctive magnetic resonance imaging features including a slow-growing, large mass in the soft tissue of the extremities in young adults, with numerous signal voids on T1-weighted and T2-weighted images, and strong enhancement after contrast.