Distribution and Rate of Myxoid Liposarcoma Spine Metastases: Impact on Surveillance Imaging.

BACKGROUND: Myxoid liposarcoma (LPS) has a unique tendency to spread to extrapulmonary sites, including osseous sites such as the spine, and adjacent sites such as the paraspinous tissue. No clear consensus exists to guide the approach to imaging in these patients. OBJECTIVE: The aim of this study was to investigate the rate and distribution of spine metastases in patients with myxoid LPS and detection modality. METHODS: Records of all patients with myxoid LPS evaluated at our sarcoma center were retrospectively reviewed. Disease patterns and imaging modality utilization were analyzed. RESULTS: Between 2000 and 2020, 164 patients with myxoid LPS were identified. The majority (n = 148, 90%) presented with localized disease, with half (n = 82, 50%) of all patients developing metastases or recurrence during their disease course. With a median follow-up of 69.2 months, spine/paraspinous metastases developed in 38 patients (23%), of whom 35 (92%) already had synchronous, non-spine metastases. Spine disease was only visible on magnetic resonance imaging (MRI), as opposed to other imaging modalities, for over one-quarter of patients with spine metastases (n = 10). For patients with metastatic disease, spine metastases were associated with worse median overall survival (2.1 vs. 8.7 years, p < 0.001). CONCLUSION: Spine metastases occurred in nearly one-quarter of patients with myxoid LPS and represented an advanced disease state, as they primarily presented in the setting of synchronous, non-spine metastases, and were associated with worse overall survival. Routine surveillance with spine MRI in patients with localized disease likely provides no benefit but may be considered in those with known metastatic disease.

Myxoid Liposarcoma Metastasizing to the Parotid Gland.

Localization of metastases into the parotid gland is a very uncommon event. Usually they arise from primary tumors located in the head and neck, mainly melanoma or epidermoid carcinoma of the skin, while other histotypes, from others anatomical districts, hardly have a metastatic spread to the parotid. Myxoid liposarcoma (MLS) is a rare malignant tumor of the soft tissue that mainly occurs in the extremities, representing the second most common subtype of liposarcoma. Although it is typical for liposarcomas to metastasize to the lungs, it is known that MLS can spread also to extra pulmonary sites. The authors report a case of myxoid liposarcoma of the left thigh in a 64-year-old man, with an unusual metastatic double presentation to the contralateral forearm first and to the parotid gland then. MLS with metastatic disease to the parotid gland is an extremely rare event with very few cases reported in the English literature.

Clinical outcomes of patients with advanced synovial sarcoma or myxoid/round cell liposarcoma treated at major cancer centers in the United States.

BACKGROUND: Outcomes data regarding advanced synovial sarcoma (SS) and myxoid/round cell liposarcoma (MRCL) are limited, consisting primarily of retrospective series and post hoc analyses of clinical trials. METHODS: In this multi-center retrospective study, data were abstracted from the medical records of 350 patients from nine sarcoma centers throughout the United States and combined into a registry. Patients with advanced/unresectable or metastatic SS (n = 249) or MRCL (n = 101) who received first-line systemic anticancer therapy and had records of tumor imaging were included. Overall survival (OS), time to next treatment, time to distant metastasis, and progression-free survival (PFS) were evaluated using the Kaplan-Meier method and Cox regression. RESULTS: At start of first-line systemic anticancer therapy, 92.4% of patients with SS and 91.1% of patients with MRCL had metastatic lesions. However, 74.7% of patients with SS and 72.3% of patients with MRCL had ≥2 lines of systemic therapy. Median OS and median PFS from first-line therapy for SS was 24.7 months (95% CI, 20.9-29.4) and 7.5 months, respectively (95% CI, 6.4-8.4). Median OS and median PFS from start of first-line therapy for MRCL was 29.9 months (95% CI, 27-44.6) and 8.9 months (95% CI 4.5-12.0). CONCLUSIONS: To the best of our knowledge, this is the largest retrospective study of patients with SS and MRCL. It provides an analysis of real-world clinical outcomes among patients treated at major sarcoma cancer centers and could inform treatment decisions and design of clinical trials. In general, the survival outcomes for this selected population appear more favorable than in published literature.

Can radiomics improve the prediction of metastatic relapse of myxoid/round cell liposarcomas?

OBJECTIVE: The strongest adverse prognostic factor in myxoid/round cell liposarcomas (MRC-LPS) is the presence of a round cell component above 5% within the tumor bulk. Its identification is underestimated on biopsies and in the neoadjuvant setting. The aim was to improve the prediction of patients' prognosis through a radiomics approach. METHODS: Thirty-five out of 89 patients with MRC-LPS managed at our sarcoma reference center from 2008 to 2017 were included in this IRB-approved retrospective study as they presented with a pre-treatment contrast-enhanced MRI (median age, 49 years old). Two radiologists reported usual conventional/semantic radiological variables. After signal intensity (SI) normalization, voxel size standardization of T2-WI, and whole tumor volume segmentation, 44 3D-radiomics features were extracted. Using least absolute shrinkage and selection operator penalized Cox regression on prefiltered features, a radiomics score based on 3 weighted radiomics features was generated. Four prognostic multivariate models for MRFS were compared using concordance index: (1) clinical model, (2) semantic radiological model, (3) radiomics model, and (4) radiomics + semantic radiological model. RESULTS: Twelve patients showed a metastatic relapse. The radiomics score included FOS_Skewness, GLRLM_LRHGE, and SHAPE_Volume and correlated with MRFS (hazard ratio = 19.37, p = 0.0009) and visual heterogeneity on T2-WI (p < 0.0001). A high score indicated a poorer prognosis. After adjustment, the best predictive performances were obtained with model (4) (concordance index = 0.937) and the lowest with model (1) (concordance index = 0.637). CONCLUSION: Adding selected radiomics features that quantify tumor heterogeneity and shape at baseline to a conventional radiological analysis improves prediction of MRC-LPS patients' prognosis. KEY POINTS: • Fourteen radiomics features quantifying shape and heterogeneity of myxoid/round cell liposarcomas on T2-WI were associated with metastatic relapse in univariate analysis. • A radiomics score based on 3 selected and weighted radiomics features was a strong and independent prognostic factor for metastatic relapse-free survival. • The best prediction of metastatic relapse-free survival for myxoid/round cell liposarcomas was achieved by combining the radiomics score to relevant radiological features.

Myxoid Liposarcoma: Prognostic Factors and Metastatic Pattern in a Series of 148 Patients Treated at a Single Institution.

OBJECTIVES: The authors reported a retrospective study on myxoid liposarcomas (MLs), evaluating factors that may influence overall survival (OS), local recurrence-free survival (LRFS), metastasis-free survival (MFS), and analyzing the metastatic pattern. METHODS: 148 MLs were analyzed. The sites of metastases were investigated. RESULTS: Margins (p = 0.002), grading (p = 0,0479), and metastasis (p < 0,0001) were significant risk factors affecting overall survival (OS). Type of presentation (p = 0.0243), grading (p = 0,0055), margin (p = 0.0001), and local recurrence (0.0437) were risk factors on metastasis-free survival (MFS). Authors did not observe statistically significant risk factors for local recurrence-free survival (LRFS) and reported 55% extrapulmonary metastases and 45% pulmonary metastases. CONCLUSION: Margins, grading, presentation, local recurrence, and metastasis were prognostic factors. Extrapulmonary metastases were more frequent in myxoid liposarcoma.

Myxoid liposarcoma: local relapse and metastatic pattern in 43 patients.

BACKGROUND: Liposarcomas are the second most common type of soft tissue sarcomas, 30-50% of these are of myxoid subtype. The aim of this retrospective study was to analyze the local control rate, the metastatic pattern and survival of patients in a consecutive single-institution series. METHODS: From 1983 to 2015, 43 patients with myxoid liposarcoma of the extremities and trunk wall underwent resections. The margin was defined as R0 (wide) or R1 (marginal). Patients were followed for evidence of local recurrence or distant metastasis. Overall and recurrence-free survival was calculated. RESULTS: The mean age was 48.6 years. The lower extremity was involved in 40 cases, the mean tumour size was 12 cm. In 31 cases a wide and in 12 cases a marginal resection was performed. Grading was G1 in 14, G2 in 25 and G3 in 4 cases. Nine patient died in follow-up, 4 of them with metastatic disease, all nonpulmonary. 5-year local recurrence (LR) free survival was 82%. 4 (9.3%) patients developed LR (all R1). Overall survival (OS) was 81% after 5 and 72% after 10 years. In multivariate analysis age and Grading proved to be significant on OS. According to univariate analysis, only age over 48 years and distant metastasis had a significant impact on overall survival. CONCLUSIONS: Patients with myxoid liposarcomas have a good prognosis. Myxoid liposarcoma has a distinct pattern of nonpulmonary metastatic disease. Therefore, patients with high-risk extremity myxoid liposarcoma should undergo imaging studies of the chest, abdomen, spine and pelvis as part of their staging and follow-up examinations preferably with whole body MRI, or CT scans and MRI of the spine and pelvic region for detection of suspected metastatic disease.

Extensive left ventricular, pulmonary artery, and pericardial metastasis from myxoid liposarcoma 16 years after the initial detection of the primary tumour: a case report and review of the literature.

Liposarcoma is regarded as the second most common soft tissue malignant tumour. Metastasis of liposarcoma to the heart is very rare, and to date, less than 40 cases have been reported in the literature. We report a 46 year-old male with myxoid liposarcoma of the lower extremity who developed extensive metastasis to the left ventricle, pulmonary artery, and pericardium. The patient presented with acute symptoms of dyspnea 16 years after surgical resection of the primary tumour, and his dyspnea progressed to cardio-respiratory arrest within the first few days of hospital admission.

Prognostic factors and outcome of Liposarcoma patients: a retrospective evaluation over 15 years.

BACKGROUND: Soft tissue sarcomas are rare entities with over 50 histological subtypes. Liposarcoma (LS) is the most common neoplasm in this group; it is a complex neoplasm that is divided into different histological subtypes. Different therapy options, such as surgical resection, radiation, and chemotherapy, are available. Depending on the subtype, location, status of the resection margins and metastatic status, different therapy options are used. Therefore, the aim of this study was to determine the prognostic factors influencing the survival of patients affected by LS with consideration for the grading, histological subtype, state of the resection margin, size, location, metastases and local recurrence in a retrospective, single-centre analysis over 15 years. METHODS: We included 133 patients (male/female = 67/66) in this study. We recorded the histologic subtype, grade, TNM classification, localization, biopsy technique, tumour margins, number of operations, complications, radiation and dose, chemotherapy, survival, recrudescence, metastases and follow-up. Survivorship analysis was performed. RESULTS: We detected 56 (43%; 95%-CI 34.6-51.6%) atypical LS cases, 21 (16.2%; 95%-CI 9.8-22.5) dedifferentiated LS cases, 40 (30.8%; 95%-CI 22.8-38.7) myxoid LS cases and 12 (9.2%; 95%-CI 4.3-14.2) pleomorphic LS cases. G1 was the most common grade, which was followed by G3. Negative margins (R0) were detected in 67 cases (53.6%; 95%-CI 44.9-62.3) after surgical resection. Local recurrence was detected in 23.6% of cases. The presence of metastases and dedifferentiated LS subtype as well as negative margins, grade and tumour size are significant prognostic factors of the survival rates (p < 0.015). CONCLUSION: Grading, LS subtype, negative margins after surgery, metastases and tumour size are independently associated with disease-specific survival, and patients with local recurrence had lower survival rates. We hope our investigation may facilitate a further prospective study and clinical decision-making in LS.

Establishment and characterization of a new human myxoid liposarcoma cell line (DL-221) with the FUS-DDIT3 translocation.

Myxoid liposarcoma has the pathognomonic fusion oncogene FUS-DDIT3 encoding a chimeric transcription factor. Metastatic risk is higher with an increased round cell component and has been linked to aberrations involving the IGFR/PI3K/AKT pathway. These molecular insights have yet to translate to targeted therapies, and the lack of experimental models is a major hindrance. We describe the initial in-depth characterization of a new cell line (DL-221) and establishment of a mouse xenograft model. The cell line DL-221 was derived from a metastatic pleural lesion showing myxoid and round cell histology. This newly established cell line was characterized for phenotypic properties and molecular cytogenetic profile, using PCR, COBRA-FISH, and western blot. Next-generation whole-exome sequencing was performed to further characterize the cell line and the parent tumor. NOD-SCID-IL2R gamma knockout mice were xenograft hosts. DL-221 cells grew an adhering monolayer and COBRA-FISH showed an aneuploid karyotype with t(12;16)(q13;p11) and several other rearrangements; RT-PCR demonstrated a FUS-DDIT3 fusion transcript type 1. Both the cell line and the original tumor harbored a TP53 compound heterozygous mutation in exon 4 and 7, and were wild-type for PIK3CA. Moreover, among the 1254 variants called by whole-exome sequencing, there was 77% concordance between the cell line and parent tumor. The recently described hotspot mutation in the TERT promoter region in myxoid liposarcomas was also found at C228T in DL-221. Xenografts suitable for additional preclinical studies were successfully established in mice after subcutaneous injection. The established DL-221 cell line is the only published available myxoid liposarcoma cell line that underwent spontaneous immortalization, without requiring SV40 transformation. The cell line and its xenograft model are unique and helpful tools to study the biology and novel potential-targeted treatment approaches for myxoid liposarcoma.

Whole-body magnetic resonance imaging in myxoid liposarcoma: A useful adjunct for the detection of extra-pulmonary metastatic disease.

Myxoid liposarcomas (MLS) are a subgroup of soft-tissue sarcomas which have a propensity for extra-pulmonary metastases. Conventional radiological staging of soft-tissue sarcomas consists of chest radiographs (CXR) and thoracic computed tomography (CT) for possible chest metastases, supplemented by magnetic resonance imaging (MRI) for local disease. The optimal radiological modality to detect extra-pulmonary metastases for systemic staging has not been proven. We reviewed the efficacy of Whole-Body MRI (WBMRI) for this purpose. 33 WBMRI and simultaneous CT scans were performed in 28 patients suffering from MLS between 2007 and 2015. 38 metastases were identified in seven patients via WBMRI. Osseous lesions predominated (spine, pelvis, chest-wall and long bones), followed by soft-tissue and abdominal lesions. Of the 29 soft-tissue or osseous metastases that were within the field-of-view of the simultaneous CT scans, five soft-tissue and zero osseous metastases were identified using CT. Metastatic disease was detected in three patients solely using WBMRI, which directly influenced their management. WBMRI is a useful adjunct in the detection of extra-pulmonary metastatic disease, which directly alters patient management. WBMRI has demonstrated an ability to identify more sites of metastatic disease compared to CT. WBMRI should be used in two situations. Firstly, at diagnosis where ablative treatment will be required e.g. amputation, when the diagnosis of occult metastasis would change treatment planning. Secondly, at diagnosis of relapse to confirm if it is a solitary site of relapse prior to consideration of metastectomy.

Early magnetic resonance imaging biomarkers to predict local control after high dose stereotactic body radiotherapy for patients with sarcoma spine metastases.

BACKGROUND CONTEXT: Recent advances in image guidance and stereotactic body radiotherapy (SBRT) have resulted in unprecedented local control for spinal metastases of all histologies. However, little is known about early imaging biomarkers of local control. PURPOSE: This study aimed to identify early magnetic resonance imaging (MRI) biomarkers to predict local control after SBRT for patients with sarcoma spine metastases. STUDY DESIGN/SETTING: This study used a retrospective case series at a large tertiary cancer center. PATIENT SAMPLE: From 2011 to 2014, 9 consecutive patients with 12 metastatic sarcoma lesions to the spine were treated with SBRT and underwent evaluation with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) both pre- and post-SBRT. OUTCOME MEASURE: Changes in perfusion metrics, including the wash-in rate constant (Ktrans), plasma volume (Vp), composite multiparametric magnetic resonance imaging (mpMRI) score, bi-dimensional tumor size, and a graded response assessment were performed and correlated to local control. METHODS: All measurements were independent and blinded by two neuroradiologists. R2 statistics were performed to document correlation, and two-tailed t tests were used to compare groups. p<.05 was deemed statistically significant. RESULTS: The median time from SBRT until posttreatment MRI was 57 days. Local failure developed in one lesion (8.3%) 10 months after SBRT. The Vp mean, Ktrans mean, Vp max, and Ktrans max were significantly decreased post-SBRT as compared with pre-SBRT (58.7%, 63.2%, 59.0%, and 55.2%; all p-values <.05). Bi-dimensional tumor measurements demonstrated an average increase in size across the cohort, and 50%, 25%, and 25% of the treated lesions demonstrated features of "worsening," "no change," or "improvement," respectively, by both radiologists' graded impressions. There was good inter-reader reliability for both size and subjective disease response scores (R2=0.84). The mpMRI score had 100% accuracy in predicting local control at time of last follow-up. There was no apparent correlation with size changes compared with the mpMRI score change post-SBRT (R2=0.026). CONCLUSIONS: We report the first analysis on the utility of DCE-MRI for metastatic sarcoma spine metastases treated with SBRT. We demonstrate that early assessment at 2 months post-SBRT using size and subjective neuroradiology impressions is insufficient to judge ultimate disease progression, and that a combination of perfusion parameters provides excellent correlation to local control.

Round cell liposarcoma metastatic to the heart.

Myxoid liposarcoma is a soft tissue tumor in adults with rare cardiac involvement. We report a 50-year-old female with high grade round cell liposarcoma of the left knee with metastases to the right heart chambers. The tumor was located in the right atrium with extension to right ventricle. The Patient underwent radiotherapy after surgical resection and 12-month follow-up revealed no recurrent cardiac disease.

FDG PET/CT findings in rare sarcomas.

The role of FDG PET/CT in management of soft tissue and bone sarcomas has been described in many studies up-to-date. However, contribution of PET/CT to diagnosis and treatment in some types of sarcomas that are seen with low incidence has not been identified properly yet. Clear cell sarcoma, synovial sarcoma of chest and myxoid lyposarcoma are rare types of sarcomas. We aimed to describe the FDG uptake patterns of these rare tumors and find out the role of FDG PET/CT in management of disease.

Round cell liposarcoma arising in the left foot: MRI and PET findings.

Liposarcomas are one of the most common soft-tissue sarcomas and commonly arise in the deep soft tissues of the extremities and retroperitoneum; however, the occurrence of liposarcomas in the foot or ankle is exceedingly rare. In this article, we present a 52-year-old man with round cell liposarcoma arising in the left foot. This tumor presented unusual manifestations of secondary osseous involvement in the metatarsal and tarsal bones of the left foot and solitary lymph node metastasis at the para-aortic region. Magnetic resonance imaging (MRI) and [(18)F]-fluoro-deoxy-glucose positron emission tomography computed tomography (FDG PET-CT) evaluation was considered to be useful for tumor grading and staging in this case.

The expanded histologic spectrum of myxoid liposarcoma with an emphasis on newly described patterns: implications for diagnosis on small biopsy specimens.

The variety of histologic patterns in myxoid liposarcoma is underappreciated. The diversity of these patterns can lead to diagnostic difficulty. We examined the morphologic spectrum of myxoid liposarcoma by cataloguing and describing different patterns identified in biopsy and resection specimens of 46 primary, recurrent, and metastatic myxoid liposarcomas. The patterns identified in the 46 cases included traditional myxoid (43 [93%]), traditional round cell (17 [37%]), pseudoacinar (24 [52%]), lipoblast-rich (13 [28%]), island (11 [24%]), lipomatous (10 [22%]), stromal hyalinization (7 [15%]), cord-like (5 [11%]), nested (3 [7%]), chondroid metaplasia (2 [4%]), and hemangiopericytoma (HPC)-like (1 [2%]). Island and nested patterns had not previously been described. The diagnosis of myxoid liposarcoma was confirmed by fluorescence in situ hybridization studies for DDIT3 (also known as CHOP) rearrangement. The morphologic spectrum of myxoid liposarcoma spans well beyond its typical appearance of spindle cells in a myxoid stroma with a prominent vascular pattern. Awareness of the variety of histologic patterns is critical to avoid misdiagnosis, especially in small biopsy specimens.

Myxoid\round cell liposarcoma (MRCLS) revisited: an analysis of 418 primarily managed cases.

BACKGROUND: Objectives of this study were to evaluate oncologic outcomes and to provide guidelines for the management of primary myxoid (MLS) and round cell liposarcoma (RCLS). METHODS: A multicenter, retrospective study of 418 cases of MRCLS primarily managed by Canadian multidisciplinary sarcoma teams. RESULTS: Study included 418 cases (MLS: 311 patients and RCLS: 107; >5% round cell) with a median age of 45 years and a median follow-up of 5.2 years. Median tumor size was 10 cm, and 81% were deep and 90% were in lower limb. The majority of patients underwent surgical resection and radiotherapy, with a small percentage (6%) receiving chemotherapy. The overall 10-year local control rate was 93% with no differences between MLS and RCLS. Radiotherapy was significant in preventing local relapse and reducing tumor diameter (median=18%) and improving microscopic margin status, but did not impact survival. Radiotherapy and the margin status were independent predictors of local recurrence. The 5- and 10-year metastatic-free survivals were 84 and 77% respectively for MLS and 69 and 46% for RCLS. The initial site of metastasis was found in multiple locations (34%) and bone involvement was frequent (40%) with predilection for spine (79%). Round cell percent (>5%) and tumor diameter (>10 cm) correlated with increased risk for metastasis and death. CONCLUSIONS: MLS and RCLS showed different metastatic risk but equally good local control. Radiotherapy was effective in preventing local recurrence and should be delivered as neoadjuvant. New staging strategies are to be defined to account for the unusual metastatic pattern.