Prognostic factors of the synovial sarcoma of the extremities: imaging does matter

Underlying synovial sarcoma undiagnosed for more than 20 years in a patient with regional pain: a case report

Synovial sarcoma (SS) is a malignant tumor comprising 5-10% of all soft tissue sarcomas. SS has distinct characteristics, such as a predilection for young adults and relatively slow growth compared to other soft tissue sarcomas. Some patients with SS experience long-standing pain at the tumor site before the development of a palpable mass. Herein, we report the case of a 39-year-old woman with SS in the upper arm who presented with pain for > 20 years. The tumor detected on magnetic resonance imaging at 17 years was an SS. To the best of our knowledge, no English-language reports on imaging study-based identification of SS, which was undiagnosed for > 20 years, are known in the literature. This report discusses the imaging features of this latent lesion and the volume-doubling time of this unusual tumor.

Differentiating low- and high-proliferative soft tissue sarcomas using conventional imaging features and radiomics on MRI

BACKGROUND

Soft-tissue sarcomas are rare tumors of the soft tissue. Recent diagnostic studies mainly dealt with conventional image analysis and included only a few cases. This study investigated whether low- and high-proliferative soft tissue sarcomas can be differentiated using conventional imaging and radiomics features on MRI.

METHODS

In this retrospective study, soft tissue sarcomas were separated into two groups according to their proliferative activity: high-proliferative (Ki-67 ≥ 20%) and low-proliferative soft tissue sarcomas (Ki-67 < 20%). Several radiomics features, and various conventional imaging features on MRI like tumor heterogeneity, peritumoral edema, peritumoral contrast-enhancement, percentage of ill-defined tumor margins, Apparent Diffusion Coefficient (ADC) values, and area under the curve (AUC) in contrast dynamics were collected. These imaging features were independently compared with the two mentioned groups.

RESULTS

118 sarcoma cases were included in this study. Metastases were more prevalent in high-proliferative soft tissue sarcomas (p < 0.001), and time till metastasis negatively correlated with the Ki-67 proliferation index (k -0.43, p = 0.021). Several radiomics features representing intratumoral heterogeneity differed significantly between both groups, especially in T2-weighted (T2w) and contrast-enhanced T1-weighted (CE-T1w) sequences. Peritumoral contrast enhancement and edema were significantly more common in soft tissue sarcomas with a high Ki-67 index (p < 0.001). Tumor configuration, heterogeneity, and ill-defined margins were commonly seen in high-proliferative soft tissue sarcomas (p = 0.001-0.008). Diffusion restriction (ADC values) and contrast dynamics (AUC values) did not present significant differences between low- and high-proliferative soft tissue sarcomas.

CONCLUSIONS

Several radiomics and conventional imaging features indicate a higher Ki-67 proliferation index in soft tissue sarcomas and can therefore be used to distinguish between low- and high-proliferative soft tissue sarcomas.

A case of synovial sarcoma of the right mid-thigh and literature review

Synovial sarcoma (SS) is a rare and malignant mesenchymal neoplasm. We report a case of a 16-year-old Chinese female diagnosed with biphasic synovial sarcoma. The imaging features, surgical procedures and pathological results of the lesion were described in detail. Additionally, we conducted a review of the literature on synovial sarcoma of the thigh over the past 2 decades, identifying a total of 25 relevant case reports and summarizing the characteristics of these cases. Synovial sarcoma has a high degree of malignancy, with a high recurrence and metastasis rate, and a 5-year survival rate of 36%-76% and a 10-year survival rate of 20%-63%, so early detection of the lesion and preoperative differential diagnosis are of paramount importance in the treatment of patients.

Inferring malignancy grade of soft tissue sarcomas from magnetic resonance imaging features: A systematic review

PURPOSE

Systematic reviews on the grading of STS using MRI are lacking. This review analyses the role of different MRI features in inferring the histological grade of STS.

MATERIALS AND METHODS

A systematic review was conducted and is reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) checklist. The electronic databases of PubMed/MEDLINE were systematically searched for literature addressing the correlation of MRI findings in soft tissue sarcoma with tumor grade. As keywords "MRI", "magnetic resonance imaging", "sarcoma", "grade", "grading", and "FNCLCC" have been selected.

RESULTS

14 studies have been included in this systematic review. Tumor size (p = 0.015 (51 patients) to p = 0.81 (36 patients)), tumor margin (p < 0.001 (95 patients) to 0.93 (36 patients)), necrosis (p = 0.004 (50 patients) to p = 0.65 (95 patients)), peritumoral edema (p = 0.002 (130 patients) to p = 0.337 (40 patients)), contrast enhancement (p < 0.01 (50 patients) to 0.019 (51 patients)) and polycyclic/multilobulated tumor configuration (p = 0.008 (71 patients)) were significantly associated with STS malignancy grade in most of the included studies. Heterogeneity in T2w images (p = 0.003 (130 patients) to 0.202 (40 patients)), signal intensity in T1w images/ hemorrhage (p = 0.02 (130 patients) to 0.5 (31 patients)), peritumoral contrast enhancement (p < 0.001 (95 patients) to 0.253 (51 patients)) and tumoral diffusion restriction (p = 0.01 (51 patients) to 0.53 (52 patients)) were regarded as significantly associated with FNCLCC grade in some of the studies which investigated these features. Most other MRI features were not significant.

CONCLUSION

Several MRI features, such as tumor size, necrosis, peritumoral edema, peritumoral contrast enhancement, intratumoral contrast enhancement, and polycyclic/multilobulated tumor configuration may indicate the malignancy grade of STS. However, further studies are needed to gain consensus.

Comment on Manole et al. Primary Pericardial Synovial Sarcoma: A Case Report and Literature Review. Diagnostics 2022, 12, 158

With great interest, we read the article by Manole et al [...].

Case report: Characteristics and nature of primary cardiac synovial sarcoma

Primary malignant cardiac tumors rarely occur, and cardiac synovial sarcoma (SS) is especially rare among such tumors. Herein, we present the case of a 35-year-old female with primary cardiac SS treated with surgery, chemotherapy, and radiotherapy. She presented with chest symptoms and underwent imaging examinations. A cardiac tumor was suspected, and an open biopsy was performed. The pathological findings suggested cardiac SS. Next, we performed a resection, and the tumors persisted at a macroscopic level. Immunohistochemistry was negative for SS18-SSX and positive for the SSX C-terminus and cytokeratin CAM5.2, a reduction of SMARCB1/INI1 was observed, and fluorescence in situ hybridization showed positive SS18 split staining. Owing to the FNCLCC grade 3 tumor and R2 margins, adjuvant chemotherapy with ifosfamide, doxorubicin, and radiotherapy was initiated, and the patient was diagnosed with cardiac SS. The differences in patients with cardiac SS compared with general SS include male predominance, larger tumor size, and poorer prognosis. Pathological findings of immunohistochemistry and fluorescence in situ hybridization were found to be more reliable than imaging findings for a correct diagnosis. Additionally, because incomplete resection is frequently performed, adjuvant therapy, including chemotherapy and radiation therapy, may be performed. The findings indicate that multiple therapies, including surgery, chemotherapy, and radiotherapy, are essential treatment strategies for improving the prognosis of patients with cardiac SS.

Synovial Sarcoma in the Extremity: Diversity of Imaging Features for Diagnosis and Prognosis

Synovial sarcomas are rare and highly aggressive soft-tissue sarcomas, primarily affecting adolescents and young adults aged 15-40 years. These tumors typically arise in the deep soft tissues, often near the large joints of the extremities. While the radiological features of these tumors are not definitely indicative, the presence of calcification in a soft-tissue mass (occurring in 30% of cases), adjacent to a joint, strongly suggests the diagnosis. Cross-sectional imaging characteristics play a crucial role in diagnosing synovial sarcomas. They often reveal significant characteristics such as multilobulation and pronounced heterogeneity (forming the "triple sign"), in addition to features like hemorrhage and fluid-fluid levels with septa (resulting in the "bowl of grapes" appearance). Nevertheless, the existence of non-aggressive features, such as gradual growth (with an average time to diagnosis of 2-4 years) and small size (initially measuring < 5 cm) with well-defined margins, can lead to an initial misclassification as a benign lesion. Larger size, older age, and higher tumor grade have been established as adverse predictive indicators for both local disease recurrence and the occurrence of metastasis. Recently, the prognostic importance of CT and MRI characteristics for synovial sarcomas was elucidated. These include factors like the absence of calcification, the presence of cystic components, hemorrhage, the bowl of grape sign, the triple sign, and intercompartmental extension. Wide surgical excision remains the established approach for definitive treatment. Gaining insight into and identifying the diverse range of presentations of synovial sarcomas, which correlate with the prognosis, might be helpful in achieving the optimal patient management.

Practical approach to ultrasound of soft tissue tumors and the added value of MRI: how I do it

This review outlines a practical approach to the everyday assessment of both non-neoplastic and neoplastic soft tissue tumors, focusing on ultrasound examination, though emphasizing the added benefit of magnetic resonance imaging in certain instances. Ultrasound approach and assessment, practical scenarios, reporting, biopsy, and follow-up are covered, as well as the criteria used to distinguish benign from malignant tumors. The potential benefits and current limitations of elastography and contrast-enhanced ultrasound in assessment are also addressed. Examples of commonly encountered soft tissue tumors are shown. Ultrasound can characterize most soft tissue masses based on their ultrasound appearance alone. Following ultrasound examination, three potential scenarios usually exist in clinical practice: (a) confident regarding diagnosis, (b) indeterminate mass with no evidence of malignancy, and (c) indeterminate mass with possibility of malignancy. A diagnostic pathway for each of these scenarios is provided. Magnetic resonance imaging is generally not helpful in further characterizing masses which are indeterminate on ultrasound assessment, though it is helpful in addressing other issues such as exact tumor location and neurovascular bundle involvement that may not be fully resolved on ultrasound examination. In these situations, magnetic resonance imaging examination can be tailored to address those specific questions that have not been adequately addressed on ultrasound examination. In this sense, both examinations are highly complementary. Tips for undertaking magnetic resonance imaging examinations are provided.

Soft-tissue sarcoma in adults: Imaging appearances, pitfalls and diagnostic algorithms

This article provides an overview of the current knowledge regarding diagnostic imaging of patients with soft-tissue sarcomas, which is a heterogeneous group of rare mesenchymal malignancies. After an initial contextualization, diagnostic flow-chart based on initial radiological findings of soft-tissue masses (with specific focus on adipocytic soft-tissue tumors [STTs], hemorragic STTs and retroperitoneal STTs) are provided considering relevant results from novel researches, guidelines, and experts' viewpoints, with the aim to help radiologists and clinicians in their practice. Particularly, the central place of sarcoma reference centers in the diagnostic and therapeutic management is highlighted, as well as the pivotal role that radiologists should play to correctly identify patients with soft-tissue sarcoma at the initial stage of the disease. Indications and methods for performing imaging-guided biopsies are also discussed, as well as clues to improve soft-tissue sarcoma grading with conventional and quantitative imaging.