The Biology of Myxofibrosarcoma: State of the Art and Future Perspectives

p53 as a Potential Actionable Target in Myxofibrosarcoma: A Molecular and Pathologic Review of a Single-Institute Series

Myxofibrosarcoma (MFS) is a common adult soft tissue sarcoma characterized by high-local recurrence rate, poorly understood molecular pathogenesis, lack of specific prognostic markers, and effective targeted therapies. To gain further insights into the disease, we analyzed a well-defined group of 133 primary MFS cases. Immunohistochemical (IHC) staining for p53, MET, RET, and RB was performed. Twenty-five cases were analyzed by targeted resequencing of known cancer driver hotspot mutations, whereas 66 and 64 MFSs were examined for the presence of genetic variants in TP53 and MET gene, respectively. All clinical, histologic, immunostaining, and genetic variables were analyzed for their impact on 5-years overall survival (OS) and 5-years event-free survival (EFS). In our series, no grade I tumors relapsed and high grade are related to a positive MET immunostaining (P = .034). Both local recurrence (P = .038) and distal metastases (P = .016) correlated to the presence of "single nucleotide variant (SNV) plus copy number variation (CNV)" in TP53. Multivariate analysis revealed that age (>60 years), metastasis at presentation, and positive IHC-p53 signal are risk factors for a poor OS (P = .003, P = .000, and P = .002), whereas age (>60 years), synchronous metastasis, and tumor size (>10 cm) predict an unfavorable 5-years EFS (P = .011, P = .000, and P = .023). Considering the smaller series (n = 66) that underwent molecular screening, the presence of "SNV+CNV" in TP53 represents a risk factor for a worse 5-years EFS (hazard ratio, 2.5; P = .017). The present series confirms that TP53 is frequently altered in MFS (86.4% of cases), appearing to play an important role in MFS tumorigenesis and being a potentially drugable target. A positive p53 immunostainings is related to a poor diagnosis, and it is the presence of a single nucleotide genetic alterations in TP53 that is essential in conferring MFS an aggressive phenotype, thus supporting the use of molecular profiling in MFS to better define the role of p53 as a prognostic factor.

Giant Myxofibrosarcoma in the Lower Limb: An Overview of Diagnostic and Clinical Management

Myxofibrosarcoma (MFS), an aggressive soft tissue sarcoma, is one of the undifferentiated pleomorphic sarcomas; it has a low incidence, affecting people in the sixth to eighth decades of life. It usually involves the extremities and is painless with a slow-growing pattern. Based on the case of a 52-year-old female patient who presented with a painful, massive, rapid-growing, ulcerated tumor of the anterior surface of the left thigh, we performed a literature review regarding the current standard of care for patients with MFS. Computed tomography examination, followed by magnetic resonance imaging and surgical biopsy with histopathological examination, confirmed the diagnosis and the presence of lung and inguinal lymph node metastases. Due to the rapid-growing pattern and the local aggressiveness, our tumor board team recommended emergency excisional surgery, with subsequent reconstructive procedures followed by referral to an oncological center. This review emphasizes the importance of proper and rapid diagnosis, followed by multidisciplinary management, for MFS cases with atypical presentation and distal metastases to improve overall outcomes.

Multiple cutaneous myxofibrosarcoma on the right arm: Clinicopathological features and differential diagnosis

The clinical presentations and pathological features of low-grade myxofibrosarcoma can be misleading, frequently resulting in diagnostic errors. An accurate diagnosis requires the application of immunohistochemistry techniques and the discerning diagnostic acumen of experienced pathologists. A 62-year-old male patient visited our outpatient clinic with multiple painful and rapidly enlarging subcutaneous nodules on his right forearm. Initially, the condition was misdiagnosed as multiple lipomas. The final pathology revealed characteristics consistent with low-grade myxofibrosarcoma.

Myxoid spindle cell sarcoma with ETV6-NTRK3 fusion

Myxoid spindle cell sarcoma is a rare sarcoma with a demanding histopathologic diagnosis due to the absence of pathognomic immunohistochemistry markers. Genetics include complex karyotypic alterations without characteristic molecular abnormalities for this entity. NTRK alterations are rare findings with great clinical importance since they can be therapeutically targeted with two NTRK inhibitors. Herein we present a case of an adult unclassified myxoid spindle cell sarcoma with ETV6/NTRK3 fusion gene, which is a molecular finding characteristic for infantile fibrosarcoma.

Sinonasal/basicranial myxofibrosarcoma: a report of 6 surgical cases combined with a literature review

OBJECTIVE

The aim of this study was to report 6 cases of sinonasal/basicranial myxofibrosarcoma and review demographic data, clinical symptoms, diagnostic methods, therapeutic methods, and prognosis on this subject in the literature.

METHODS

We conducted a retrospective analysis of six patients referred to our hospital during a 10-year period from 2010 to 2020.

RESULTS

In this series, there were four males and two females. The tumours originated from the maxillary sinus in all six cases. The symptoms were nonspecific, and all patients underwent endoscopic resection alone or combined with open resection. The postoperative period was uneventful. All patients were diagnosed with myxofibrosarcoma. After a median follow-up period of 36 (6-52) months, the recurrence rate of MFS was 66.7% (4/6), and the mortality rate was 50% (3/6).

CONCLUSION

Sinonasal/basicranial MFS is a rare neoplasm, and the most common primary site is the maxillary sinus. When diagnosing MFS, osteolysis may help rule out benign lesions. So far surgery is the mainstay of treatment for sinonasal/basicranial MFS. Our surgical strategy using endoscopic resection or endoscopic resection combined with open resection to achieve a negative surgical margin and using re-excision operations to treat relapsed cases may be recommended to rhinologists who treat MFS. Prospective randomised trials are needed to study the role of chemotherapy, radiotherapy, and our surgical strategy for sinonasal/basicranial MFS. Diagnosing patients at an earlier stage and better patient compliance with follow-up plans may improve the prognosis of patients.

Margin Assessment in Soft Tissue Sarcomas: Review of the Literature

Simple Summary

Many classifications to assess margins status for soft tissue sarcomas are reported in the literature. Most of the series are heterogeneous and variable in size, making it difficult to compare results from study to study. Thus, which is the best way to assess margins in order to predict the risk of local recurrence is still debated. The aim of this narrative review is to provide a comprehensive assessment of the literature on margins, and to highlight the need for a uniform description of the margin status for patients with soft tissue sarcomas (STS).

Abstract

Adequacy of margins must take into consideration both the resection margin width (quantity) and anatomic barrier (quality). There are several classification schemes for reporting surgical resection margin status for soft tissue sarcomas (STS). Most of the studies regarding treatment outcomes in STS included all histologic grades and histological subtypes, which include infiltrative and non-infiltrative subtypes and are very heterogeneous in terms of both histologic characteristics and treatment modalities (adjuvant treatments or not). This lack of consistency makes it difficult to compare results from study to study. Therefore, there is a great need for evidence-based standardization concerning the width of resection margins. The aim of this narrative review is to provide a comprehensive assessment of the literature on margins, and to highlight the need for a uniform description of the margin status for patients with STS. Patient cases should be discussed at multidisciplinary tumor boards and treatments should be individualized to clinical and demographic characteristics, which must include also a deep knowledge of specific histotypes behaviors, particularly infiltrative ones.

Metastatic Myxofibrosarcoma with Durable Response to Temozolomide Followed by Atezolizumab: A Case Report

Myxofibrosarcoma (MFS) is a well-recognized histotype of soft tissue sarcomas that generally presents with localized disease. Herein, we describe the case of a patient with metastatic MFS who experienced durable response to sixth-line therapy with temozolomide. Upon further progression, his tumor was notable for a high tumor mutational burden, and he was subsequently treated with seventh-line immunotherapy, atezolizumab, achieving a second durable response. This case highlights the role of immunotherapy after administration of alkylating agents. Review of the literature indicates that recurrent tumors treated with alkylating agents often experience hypermutation as a means of developing resistance and that checkpoint inhibitors are subsequently effective in these tumors. KEY POINTS: To the authors' knowledge, this is the first report of a patient with myxofibrosarcoma with high tumor mutational burden after administration of temozolomide monotherapy. Hypermutation may be a resistance mechanism for patients with soft tissue sarcoma who develop resistance to alkylating agents. Checkpoint inhibition may be effective therapy in patients with soft tissue sarcoma with high tumor mutational burden as a consequence of alternate systemic therapy resistance.

Gemcitabine-Containing Chemotherapy for the Treatment of Metastatic Myxofibrosarcoma Refractory to Doxorubicin: A Case Series

Background: Myxofibrosarcoma is a type of soft-tissue sarcoma that is associated with high rates of local recurrence and distant metastases. The first-line treatment for metastatic soft-tissue sarcoma has conventionally been doxorubicin-based. Recent evidence suggests that myxofibrosarcoma may be molecularly similar to undifferentiated pleomorphic sarcoma (UPS), which is particularly sensitive to gemcitabine-based therapy. The goal of this study was to evaluate the activity of gemcitabine-containing regimens for the treatment of metastatic myxofibrosarcoma refractory to doxorubicin. Material and Methods: We retrospectively evaluated seven consecutive cases of metastatic myxofibrosarcoma at our institution treated with gemcitabine-based therapy in the second-line setting, after progression on doxorubicin. Baseline clinical and baseline characteristics were collected. Primary endpoints were objective response rate (ORR), progression-free survival (PFS) and overall survival (OS). Results: After progression on first-line doxorubicin, a partial, or complete radiological response was observed in four of seven patients who received gemcitabine-based chemotherapy. With a median follow-up of 14 months, median progression-free and overall survival were 8.5 months and 11.4 months, respectively. Conclusions: Gemcitabine-based chemotherapy was associated with encouraging response rates in this cohort, similar to those seen in UPS. Both entities could be studied together for novel gemcitabine-based regimens.

Development and validation of a prognostic nomogram for predicting the overall survival of myxofibrosarcoma patients: a large population-based study

Background

Although some studies have explored prognostic factors of myxofibrosarcoma (MFS), the sample sizes were small, generally fewer than 100 patients. There is still no effective prognostic model for MFS patients based on a large population and comprehensive factors. The present study was designed to establish and validate a large population-based, clinically relevant prognostic nomogram for predicting 3- and 5-year overall survival (OS) in patients with MFS.

Methods

We identified patients with MFS (ICD-O-3 code: 8811/3) who were diagnosed between 2004 and 2015 from the Surveillance, Epidemiology, and End Results database and separated them into training and validation cohorts (7:3 ratio). Survival was described using the Kaplan-Meier method. Univariate and multivariate Cox regression analyses were used to identify prognostic factors of survival. An individual nomogram was established to predict OS at 3 and 5 years in MFS patients. The discriminative ability and predictive accuracy of the nomogram were compared to those of the traditional American Joint Committee on Cancer (AJCC) staging system in the training and validation cohorts. Finally, MFS patients were divided into two subgroups based on the prognostic index (PI) score of the nomogram, and the survival outcomes of the subgroups were compared.

Results

A total of 1,270 patients were included. Age at diagnosis, total number of in situ or malignant tumors, tumor size, tumor site, tumor extension, AJCC stage, surgical status, chemotherapy, and radiotherapy were the independent predictors of survival and were included in the nomogram. The nomogram had C-indexes of 0.806 in the training cohort and 0.783 in the validation cohort, which were greater than those of the sixth edition of the AJCC staging system (training cohort, 0.669 and validation cohort, 0.674). Decision curve analysis (DCA) revealed that the nomogram was useful with high clinical net benefits. Survival outcomes were significantly different between the different risk subgroups (P<0.001).

Conclusions

A novel nomogram based on a large population was constructed to evaluate survival outcomes for MFS. Its predictive efficacy was markedly superior than that of the traditional sixth edition of the AJCC staging system.

Systemic Inflammation Is Associated with Oncological Outcome in Patients with High-Grade Myxofibrosarcoma of the Extremities: A Retrospective Analysis

BACKGROUND

The aim of this retrospective study is to verify whether preoperative systemic inflammatory markers (serum C-reactive protein [CRP] and neutrophil-lymphocyte ratio [NLR]) can help in predicting the disease-specific survival (DSS) and local recurrence (LR) rate in adult patients affected by localized myxofibrosarcoma (MFS) of the extremities.

METHODS

We reviewed 126 adult patients with primary, localized MFS of the limbs. We analyzed DSS and LR.

RESULTS

Median age at the time of surgery was 68 years (range 19-92). Median CRP was 0.4 mg/dL and median NLR was 2.8. A worse DSS was found in patients who had preoperative CRP >0.5 mg/dL (p = 0.002) and in those with NLR >3.5 (p < 0.001). In multivariate analysis, tumor size and grade as well as preoperative CRP values and NLR were confirmed to be prognostic factors in terms of DSS. An increased risk of LR was found in multivariate analysis in patients with a tail sign and with high gadolinium enhancement at preoperative MRI.

CONCLUSIONS

Patients with high preoperative CRP and NLR levels, as well as large and high-grade tumors, might be considered as candidates for additional, more aggressive treatment approaches or more stringent follow-up schedules.