Superior scapular location: An overlooked albeit frequent finding in elastofibroma dorsi.

PURPOSE: To explore the frequency of superior scapular elastofibroma dorsi in a large patient series with elastofibroma dorsi. METHODS: 136 chest CTs from January 2016 to July 2022 reporting elastofibroma dorsi were retrospectively analyzed. Three radiologists assessed the number, size, and location of elastofibroma dorsi. Continuous variables underwent two-tailed t-tests with p < 0.05. Inter-observer agreement was assessed by using Cohen's Kappa values. RESULTS: In 136 patients (mean age, 75.9 +/- 9.8 years; 117 female), 330 elastofibroma dorsi were found. Six (4.4 %) patients had single, 87 (64 %) double, 22 (16.2 %) triple and 21 (15.4 %) quadruple lesions. All single and double lesions were in the inferior scapular regions. 43 (31.6 %) patients had superior scapular lesions in addition to inferior scapular elastofibroma dorsi. Inferior scapular elastofibroma dorsi was significantly larger than superior scapular elastofibroma dorsi. The probability of a right superior lesion was significantly higher in patients with a larger right inferior lesion. Inter-observer agreement was very good for experienced radiologist (κ = 94.1) and good for other radiologists (κ = 79.4 and κ = 78). CONCLUSION: In contrast to current belief, superior scapular elastofibroma dorsi accompanying the typical inferior scapular lesions is not uncommon and can even manifest bilaterally. To the best of our knowledge, this is the first case series reporting prevalence of quadruple elastofibroma dorsi.

Myoepithelial Carcinoma of Soft Tissue: Report of Two Cases.

CASE: A 40-year-old man was evaluated for a painful mass on his right calf, and a 36-year-old woman presented with a painless mass on her right foot. Final pathology revealed marked nuclear atypia and positivity for S100/SOX10 and AE1/AE3 confirming diagnoses of myoepithelial carcinoma. Both patients underwent surgical resection and are without evidence of local recurrence or metastatic disease at 1-year follow-up. CONCLUSION: Soft-tissue tumors presenting in the extremities warrant careful evaluation and timely histopathologic diagnosis. Myoepithelial carcinomas are rare, aggressive tumors with a propensity for local recurrence and metastasis. Treatment of these tumors should be discussed by a multidisciplinary tumor team.

Generation of post-surgical minimal residual disease models to investigate metastasis in soft tissue sarcoma patient-derived orthotopic xenografts.

Despite optimal multimodal treatment including surgical resection, 50%-80% of high-grade soft tissue sarcoma (STS) patients metastasize. Here, we present a protocol for the generation and use of post-surgical minimal residual disease models to investigate metastatic relapse in STS patient-derived xenografts. We describe steps for orthotopic engraftment of high-grade STS patient-derived tumor tissue. We then detail procedures for primary tumor resection with broad, negative resection margins and follow-up until metastases using MRI. For complete details on the use and execution of this protocol, please refer to Fischer et al. (2023).1.

Magnetic Resonance Imaging Biomarkers of Bone and Soft Tissue Tumors.

Magnetic resonance imaging (MRI) is essential in the management of musculoskeletal (MSK) tumors. This review delves into the diverse MRI modalities, focusing on anatomical, functional, and metabolic sequences that provide essential biomarkers for tumor detection, characterization, disease extent determination, and assessment of treatment response. MRI's multimodal capabilities offer a range of biomarkers that enhance MSK tumor evaluation, aiding in better patient management.

Radiomics in Musculoskeletal Tumors.

Sarcomas are heterogeneous rare tumors predominantly affecting the musculoskeletal (MSK) system. Due to significant variations in their natural history and variable response to conventional treatments, the discovery of novel diagnostic and prognostic biomarkers to guide therapeutic decision-making is an active and ongoing field of research. As new cellular, molecular, and metabolic biomarkers continue to be discovered, quantitative radiologic imaging is becoming increasingly important in sarcoma management. Radiomics offers the potential for discovering novel imaging diagnostic and predictive biomarkers using standard-of-care medical imaging. In this review, we detail the core concepts of radiomics and the application of radiomics to date in MSK sarcoma research. Also described are specific challenges related to radiomic studies, as well as viewpoints on clinical adoption and future perspectives in the field.

The role of 18F-FDG PET in minimizing variability in gross tumor volume delineation of soft tissue sarcomas.

BACKGROUND: Accurate gross tumor volume (GTV) delineation is a critical step in radiation therapy treatment planning. However, it is reader dependent and thus susceptible to intra- and inter-reader variability. GTV delineation of soft tissue sarcoma (STS) often relies on CT and MR images. PURPOSE: This study investigates the potential role of 18F-FDG PET in reducing intra- and inter-reader variability thereby improving reproducibility of GTV delineation in STS, without incurring additional costs or radiation exposure. MATERIALS AND METHODS: Three readers performed independent GTV delineation of 61 patients with STS using first CT and MR followed by CT, MR, and 18F-FDG PET images. Each reader performed a total of six delineation trials, three trials per imaging modality group. Dice Similarity Coefficient (DSC) score and Hausdorff distance (HD) were used to assess both intra- and inter-reader variability using generated simultaneous truth and performance level estimation (STAPLE) GTVs as ground truth. Statistical analysis was performed using a Wilcoxon signed-ranked test. RESULTS: There was a statistically significant decrease in both intra- and inter-reader variability in GTV delineation using CT, MR 18F-FDG PET images vs. CT and MR images. This was translated by an increase in the DSC score and a decrease in the HD for GTVs drawn from CT, MR and 18F-FDG PET images vs. GTVs drawn from CT and MR for all readers and across all three trials. CONCLUSION: Incorporation of 18F-FDG PET into CT and MR images decreased intra- and inter-reader variability and subsequently increased reproducibility of GTV delineation in STS.

Impact of CT and MRI in the diagnostic workup of malignant triton tumour-a monocentric analysis and review of the literature.

OBJECTIVES: Malignant triton tumours (MTTs) are rare but aggressive subtypes of malignant peripheral nerve sheath tumours (MPNSTs) with a high recurrence rate and 5-year survival of 14%. Systematic imaging data on MTTs are scarce and mainly based on single case reports. Therefore, we aimed to identify typical CT and MRI features to improve early diagnosis rates of this uncommon entity. METHODS: A systematic review on literature published until December 2022 on imaging characteristics of MTTs was performed. Based on that, we conducted a retrospective, monocentric analysis of patients with histopathologically proven MTTs from our department. Explorative data analysis was performed. RESULTS: Initially, 29 studies on 34 patients (31.42 ± 22.6 years, 12 female) were evaluated: Literature described primary MTTs as huge, lobulated tumours (108 ± 99.3 mm) with central necrosis (56% [19/34]), low T1w (81% [17/21]), high T2w signal (90% [19/21]) and inhomogeneous enhancement on MRI (54% [7/13]). Analysis of 16 patients (48.9 ± 13.8 years; 9 female) from our institution revealed comparable results: primary MTTs showed large, lobulated masses (118 mm ± 64.9) with necrotic areas (92% [11/12]). MRI revealed low T1w (100% [7/7]), high T2w signal (100% [7/7]) and inhomogeneous enhancement (86% [6/7]). Local recurrences and soft-tissue metastases mimicked these features, while nonsoft-tissue metastases appeared unspecific. CONCLUSIONS: MTTs show characteristic features on CT and MRI. However, these do not allow a reliable differentiation between MTTs and other MPNSTs based on imaging alone. Therefore, additional histopathological analysis is required. ADVANCES IN KNOWLEDGE: This largest published systematic analysis on MTT imaging revealed typical but unspecific imaging features that do not allow a reliable, imaging-based differentiation between MTTs and other MPNSTs. Hence, additional histopathological analysis remains essential.

Soft-Tissue Sarcomas of the Genitourinary Tract with Radiologic-Pathologic Correlation.

Genitourinary tract soft-tissue sarcomas are rare neoplasms with varied pathologic and clinical features. While some of these tumors may be aggressive high-grade malignancies, others are low grade with a relatively better prognosis. Given that the grade and extent of the disease are important prognostic factors in these tumors, timely diagnosis is crucial. Unfortunately, most imaging features of these malignancies are not pathognomonic, and various histologic subtypes do not manifest with typical classic imaging features. Therefore, reliable differentiation of the various histologic tumor types is not always possible based solely on the radiologic manifestations. Imaging findings need to be considered in the context of clinical history in corroboration with radiologic-pathologic correlation. The authors discuss the specific imaging and pathologic characteristics of various genitourinary tract soft-tissue sarcomas, emphasizing diagnostic difficulties and differential diagnoses. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Sclerosing epithelioid fibrosarcoma of bone with hybrid features: clinicopathologic, radiologic, and molecular analysis of three cases.

Sclerosing epithelioid fibrosarcoma (SEF) occurring as a primary bone tumor is exceptionally uncommon. Even more rare are cases of SEF that show morphologic overlap with low-grade fibromyxoid sarcoma (LGFMS). Such hybrid lesions arising within the bone have only rarely been reported in the literature. Due to their variegated histomorphology and non-specific radiologic features, these tumors may pose diagnostic difficulties. Herein we describe three molecularly confirmed primary bone cases of sclerosing epithelioid fibrosarcoma that demonstrated prominent areas showing the features of LGFMS and with areas resembling so-called hyalinizing spindle cell tumor with giant rosettes (HSCTGR). Two patients were female and one was male aged 26, 47, and 16, respectively. The tumors occurred in the femoral head, clavicle, and temporal bone. Imaging studies demonstrated relatively well-circumscribed radiolucent bone lesions with enhancement on MRI. Cortical breakthrough and soft tissue extension were present in one case. Histologically the tumors all demonstrated hyalinized areas with SEF-like morphology as well as spindled and myxoid areas with LGFMS-like morphology. Two cases demonstrated focal areas with rosette-like architecture as seen in HSCTGR. The tumors were all positive for MUC4 by immunohistochemistry and cytogenetics, fluorescence in-situ hybridization, and next-generation sequencing studies identified EWSR1 gene rearrangements confirming the diagnosis in all three cases.Hybrid SEF is exceedingly rare as a primary bone tumor and can be difficult to distinguish from other low-grade spindled and epithelioid lesions of bone. MUC4 positivity and identification of underlying EWSR1 gene rearrangements help support this diagnosis and exclude other tumor types.

Radio-Guided Occult Lesion Localization With 99m Tc for the Localization of Nonpalpable Melanoma and Soft Tissue Sarcoma Lesions: A Feasibility Study.

PURPOSE OF THE REPORT: Localization techniques are needed to facilitate resection of nonpalpable lesions. In this study, the feasibility of radio-guided occult lesion localization (ROLL) with 99m Tc is investigated for the localization of nonpalpable, small, suspicious, or proven melanoma or soft tissue sarcoma lesions at various locations throughout the body. PATIENTS AND METHODS: Patients with nonpalpable, suspicious, or proven melanoma or soft tissue sarcoma lesions were selected for this study. Within 24 hours before surgery, a median dose of 33.92 MBq 99m Tc-labeled human albumin particles ( 99m Tc-NA or 99m Tc-MAA) was injected in the lesion under ultrasound guidance. A hand-held gamma probe was used to detect the radioactive signal and guidance during surgery. RESULTS: In this study, 20 patients with a total of 25 lesions were included and analyzed. The median size of the lesions was 1.8 cm (interquartile range [IQR], 1.8-4.0 cm), of which 44% were intramuscular located and 36% were subcutaneous, and 20% consisted of suspicious lymph nodes, mostly in the lower extremity. At median 4 hours (IQR, 3-6 hours) postinjection, 99m Tc ROLL showed a 100% intraoperative identification rate with proper signal identification with the gamma probe in all patients. With a median surgery time of 76 minutes (IQR, 45-157 minutes), all targeted lesions could be resected without 99m Tc-related complications, resulting in 88% microscopically margin-negative resection. No reoperations were needed for the same lesion. CONCLUSIONS: The 99m Tc ROLL procedure is feasible for the localization and excision of small, nonpalpable melanoma and soft tissue sarcoma lesions at various locations in the body.

Management of tumor volume changes during preoperative radiotherapy for extremity soft tissue sarcoma: a new strategy of adaptive radiotherapy.

BACKGROUND: Using adaptive radiotherapy (ART), to determine objective clinical criteria that identify extremity soft tissue sarcoma (ESTS) patients requiring adaptation of their preoperative radiotherapy (RT) plan. PATIENTS AND METHODS: We included 17 patients with a lower extremity ESTS treated between 2019 and 2021 with preoperative RT, using helicoidal intensity-modulated RT (IMRT) tomotherapy, before surgical resection. We collected clinical, tumor parameters and treatment data. Repositioning was ascertained by daily Megavoltage computed tomography (MVCT) imaging. Using the PreciseART technology we retrospectively manually delineated at least one MVCT for each patient per week and recorded volume and dosimetric parameters. A greater than 5% change between target volume and planned target volume (PTV) dosimetric coverage from the initial planning CT scan to at least one MVCT was defined as clinically significant. RESULTS: All 17 patients experienced significant tumor volume changes during treatment; 7 tumors grew (41%) and 10 shrank (59%). Three patients (18%), all undifferentiated pleomorphic sarcomas (UPS) with increased volume changes, experienced significant reductions in tumor dose coverage. Seven patients required a plan adaptation, as determined by practical criteria applied in our departmental practice. Among these patients, only one ultimately experienced a significant change in PTV coverage. Three patients had a PTV decrease of coverage. Among them, 2 did not receive plan adaptation according our criteria. None of the patients with decreased tumor volumes had reduced target volume coverage. Monitoring volume variations by estimating gross tumor volume (GTV) on MVCT, in addition to axial and sagittal linear tumor dimensions, appeared to be most effective for detecting reductions in PTV coverage throughout treatment. CONCLUSIONS: Variations in ESTS volume are evident during preoperative RT, but significant dosimetric variations are rare. Specific attention should be paid to grade 2-3 UPSs during the first 2 weeks of treatment. In the absence of dedicated software in routine clinical practice, monitoring of tumor volume changes by estimating GTV may represent a useful strategy for identifying patients whose treatment needs to be replanned.

Neuroblastoma with superficial soft tissue mass as the first symptom: case reports with atypical ultrasonic image and literature review.

Neuroblastoma is one of the most common tumors in children. Cases where an isolated soft-tissue metastasis mass is the initial symptom are rare, with only four such cases reported to date. We describe the imaging findings of ten cases of neuroblastoma patients in our hospital with superficial soft tissue mass (SSTM) as the primary symptom. The main ultrasound finding of SSTM was hypoechoic masses or scattered speck-like hyperechoic masses. However, when this type of SSTM is caused by soft tissue metastasis, the location is often atypical, and ultrasound findings are difficult to distinguish from other benign diseases. Therefore, this research should remind clinicians to recognize atypical presentations of this common childhood malignant tumor. Radiologists should also consider the possibility of neuroblastoma when finding this type of SSTM with atypical ultrasound features.

Ultrasound performance in pediatric deep soft-tissue tumor characterization.

This study investigated the performance of ultrasonography in diagnosing deep soft-tissue tumors and tumor-like lesions in children with histological results. Demographic information and ultrasound characteristics of benign and malignant masses were statistically analyzed. Three radiologists (Radiologists 1, 2, and 3) independently reviewed the ultrasonography studies while being blinded to the medical history and other imaging findings. The 82 lesions included in the study were histopathologically classified as malignant (n = 25) or benign (n = 57). No statistically significant differences were observed between the benign and malignant subgroups regarding age (p = 0.059), sex (p = 1.0), disease course (p = 0.812), presence or absence of symptoms (p = 0.534), maximum diameter (p = 0.359), margin (p = 1.0), calcification (p = 0.057), or blood Adler type (p = 0.563). However, statistically significant differences were observed between the benign and malignant subgroups in terms of isolated or Multiple occurrences (p < 0.001), history of malignancy (p < 0.001), shape (p < 0.001), and echogenicity (p < 0.001). Parameters such as tumor shape (p = 0.042, OR = 6.222), single or multiple occurrences (p = 0.008, OR = 17.000), and history of malignancy (p = 0.038, OR = 13.962) were identified as independent predictors of benign and malignant tumors. The diagnostic sensitivities evaluated by the three radiologists were 68.0%, 72.0%, 96.0%, respectively, while the specificities were 77.2%, 82.5%, 77.2%, respectively. Ultrasound demonstrates good performance in the diagnosis of benign deep lesions such as hemangiomas/venous malformation and adipocytic tumors. Multiple irregular morphologies and a history of malignancy were identified as independent risk factors for malignant masses. The experience of radiologists in recognizing specific tumors is important. Careful attention should be paid to masses with ambiguous ultrasound features, as well as small lesions.

Pleomorphic liposarcoma of the extremity with solitary huge liver metastasis at initial diagnosis treated with conversion surgery combined with adjuvant chemotherapy: a case report.

BACKGROUND: Pleomorphic liposarcoma is the rarest subtype of liposarcoma. Pleomorphic liposarcomas are generally unresponsive to chemotherapy and radiotherapy. Moreover, metastasis in the liver, as the first and sole site, from a primary extremity soft tissue sarcoma, including pleomorphic liposarcoma, is extremely rare. Information regarding the appropriate management of these lesions is limited. CASE PRESENTATION: A 50-year-old Japanese woman presented with a mass in the left thigh. Imaging examination revealed a soft tissue sarcoma on the left posterior thigh. The tumor was histologically diagnosed as pleomorphic liposarcoma. Computed tomography examination for assessment of metastases incidentally detected a huge liver mass. Wide excision of sarcoma was performed prior to chemotherapy. Right trisectionectomy was necessary to achieve hepatic clearance; however, the future liver remnant volume was insufficient. Therefore, we decided to administer anthracycline-based chemotheraphy to shrink the tumor. After seven courses of adriamycin-based chemotherapy, the liver tumor size was reduced from 211 mm × 106 mm × 180 mm to 105 mm × 66 mm × 90 mm. Finally, a right hemihepatectomy was performed. The patient was continuously monitored and was metastasis or local recurrence free within 5 months after liver surgery. CONCLUSION: Chemotherapy is effective in some cases for the treatment of unresectable liver metastases of pleomorphic liposarcoma, and complete resection is possible with conversion surgery. If the patient's general condition permits, anthracycline-based chemotherapy can be used for the treatment of stage 4 pleomorphic liposarcoma.

Research status and progress of radiomics in bone and soft tissue tumors: A review.

Bone and soft tissue tumors are diverse, accompanying by complex histological components and significantly divergent biological behaviors. It is a challenge to address the demand for qualitative imaging as traditional imaging is restricted to the detection of anatomical structures and aberrant signals. With the improvement of digitalization in hospitals and medical centers, the introduction of electronic medical records and easier access to large amounts of information coupled with the improved computational power, traditional medicine has evolved into the combination of human brain, minimal data, and artificial intelligence. Scholars are committed to mining deeper levels of imaging data, and radiomics is worthy of promotion. Radiomics extracts subvisual quantitative features, analyzes them based on medical images, and quantifies tumor heterogeneity by outlining the region of interest and modeling. Two observers separately examined PubMed, Web of Science and CNKI to find existing studies, case reports, and clinical guidelines about research status and progress of radiomics in bone and soft tissue tumors from January 2010 to February 2023. When evaluating the literature, factors such as patient age, medical history, and severity of the condition will be considered. This narrative review summarizes the application and progress of radiomics in bone and soft tissue tumors.

Myxoid liposarcoma: MRI features with histological correlation.

BACKGROUND AND AIMS: Myxoid liposarcoma is classified in the group of sarcomas with adipose differentiation, which is the second most common group of sarcomas. However, myxoid liposarcoma is not a homogeneous entity, because the behavior and clinical course of these tumours can vary widely. This study aimed to describe the magnetic resonance imaging (MRI) features of myxoid liposarcomas and to determine whether the MRI features are associated with the histologic grade and can differentiate between low-grade and high-grade tumours and thus help in clinical decision making. MATERIAL AND METHODS: We studied 36 patients with myxoid liposarcomas treated at our centre between 2010 and 2018. We analysed clinical variables (age, sex, and tumour site) and MRI features (size, depth, borders, fatty component, myxoid component, non-fatty/non-myxoid component, apparent diffusion coefficient (ADC), and type of enhancement after the administration of intravenous contrast material). We correlated the MRI features with the histologic grade and the percentage of round cells. RESULTS: In our series, patients with myxoid liposarcomas were mainly young adults (median age, 43 years). There were no differences between sexes; 97.2% were located in the lower limbs, 86.1% were deep, and 77.8% had well-defined borders. Of the 23 myxoid liposarcomas that contained no fat, 16 (69.6%) were high grade (p = 0.01). All the tumors with a myxoid component of less than 25% were high grade (p = 0.01); 83.3% of those with a non-fatty/non-myxoid component greater than 50% were high grade (p = 0.03) and 61.5% had more than 5% round cells (p = 0.01). Diffusion sequences were obtained in 14 of the 36 patients; ADC values were high (median, 2 × 10-3 mm2/s), although there were no significant associations between low-grade and high-grade tumours. Contrast-enhanced images were available for 30 (83.3%) patients; 83.3% of the tumours with heterogeneous enhancement were high grade (p = 0.01). CONCLUSIONS: MRI can be useful for differentiating between high- and low-grade myxoid liposarcomas and can help in clinical decision making.

Intratumoral and peritumoral MRI-based radiomics prediction of histopathological grade in soft tissue sarcomas: a two-center study.

OBJECTIVES: This study aims to develop a model based on intratumoral and peritumoral radiomics from fat-suppressed T2-weighted(FS-T2WI) images to predict the histopathological grade of soft tissue sarcoma (STS). METHODS: This retrospective study included 160 patients with STS from two centers, of which 82 were low-grade and 78were high-grade. Radiomics features were extracted and selected from the region of tumor mass volume (TMV) and peritumoral tumor volume (PTV) respectively. The TMV, PTV, and combined(TM-PTV) radiomics models were established in the training cohort (n = 111)for the prediction of histopathological grade. Finally, a radiomics nomogram was constructed by combining the TM-PTV radiomics signature (Rad-score) and the selected clinical-MRI predictor. The ROC and calibration curves were used to determine the performance of the TMV, PTV, and TM-PTV models in the training and validation cohort (n = 49). The decision curve analysis (DCA) and calibration curves were used to investigate the clinical usefulness and calibration of the nomogram, respectively. RESULTS: The TMV model, PTV model, and TM-PTV model had AUCs of 0.835, 0.879, and 0.917 in the training cohort and 0.811, 0.756, 0.896 in the validation cohort. The nomogram, including the TM-PTV signatures and peritumoral hyperintensity, achieved good calibration and discrimination with a C-index of 0.948 (95% CI, 0.906 to 0.990) in the training cohort and 0.921 (95% CI, 0.840 to 0.995) in the validation cohort. Decision curve analysis demonstrated the clinical usefulness of the nomogram. CONCLUSION: The proposed model based on intratumoral and peritumoral radiomics showed good performance in distinguishing low-grade from high-grade STSs.