Myxofibrosarcoma: prognostic factors and survival in a series of patients treated at a single institution

When Is It Important to Sequence Sarcomas and Other Mesenchymal Neoplasms? A Practical Guide to Molecular Testing

The increasingly widespread availability of next-generation sequencing has led to its incorporation as a diagnostic tool in pathology and a modality for identifying targetable alterations. However, sequencing is still a somewhat expensive and time-consuming. Here, we discuss tumor types for which (1) molecular testing is not generally indicated, (2) surrogate immunohistochemical markers have rendered molecular testing unnecessary, or (3) sequencing is important for diagnostic and therapeutic purposes. We also provide a practical framework to assist in decision-making for molecular testing of both classified and unclassified mesenchymal neoplasms, reflecting our practice in a tertiary sarcoma referral center.

Establishment and characterization of the novel myxofibrosarcoma cell line, SMU-MFS

Myxofibrosarcoma (MFS) is one of the most common soft-tissue sarcomas in elderly patients. Owing to the limited efficacy of chemotherapy and radiotherapy, complete resection is the only available curative treatment. Therefore, developing novel therapies for MFS is important to improve clinical outcomes. Herein, a novel MFS cell line, namely SMU-MFS, was established to better understand the biologic characteristics of MFS and develop new therapies. A tissue sample from the surgically resected tumor tissue of a 56-year-old patient with a tumor was subjected to primary culture. The cell line was established and authenticated by assessing the short tandem repeats of DNA microsatellites. The monolayer cultures of SMU-MFS cells exhibited constant growth, spheroid formation, and invasive capacity. Furthermore, the cells exhibited low chemosensitivity to doxorubicin, eribulin, and pazopanib, which are used to inhibit metastatic progression. In addition, of the four mice inoculated with SMU-MFS cells, tumors developed in two mice after 8 weeks. Altogether, the findings of this study suggest that the SMU-MFS cell line can be a useful tool for investigating MFS development and evaluating novel therapeutic agents.

Establishment and characterization of two novel patient-derived cell lines from myxofibrosarcoma: NCC-MFS7-C1 and NCC-MFS8-C1

Myxofibrosarcoma (MFS), an aggressive soft tissue sarcoma, presents a significant challenge because of its high recurrence rate, distal metastasis, and complex genetic background. Although surgical resection is the standard treatment for MFS, the outcomes are unsatisfactory and effective non-surgical treatment strategies, including drug therapy, are urgently warranted. MFS is a rare tumor that requires comprehensive preclinical research to develop promising drug therapies; however, only two MFS cell lines are publicly available worldwide. The present study reports two novel patient-derived MFS cell lines, NCC-MFS7-C1 and NCC-MFS8-C1. These cell lines have been extensively characterized for their genetic profile, proliferation, spheroid-forming capacity, and invasive behavior, confirming that they retain MFS hallmarks. Furthermore, we conducted comprehensive drug screening against these cell lines and six others previously established in our laboratory to identify potential therapeutic candidates for MFS. Among the screened agents, actinomycin D, bortezomib, and romidepsin demonstrated considerable antiproliferative effects that were superior to those of doxorubicin, a standard drug, highlighting their potential as novel drugs. In conclusion, NCC-MFS7-C1 and NCC-MFS8-C1 are valuable research resources that contribute to the understanding of the pathogenesis and development of novel therapies for MFS.

The effect of radiation or chemotherapy on the local recurrence, overall survival, and distant metastasis in patients with myxofibrosarcoma: A systematic review

BACKGROUND AND OBJECTIVES

Management of myxofibrosarcoma (MFS) is widely debated, and there is no consensus regarding the effect of adjuvant therapies on local recurrence (LR), distant metastasis (DM), or overall survival (OS). This study aims to determine the effect of adjuvant therapies on the aforementioned outcomes in patients with MFS.

METHODS

We conducted a systematic review via Medline, PubMed, CINAHL, Cochrane, Embase, and Google Scholar. Therapeutic studies that reported LR, DM, and OS following adjuvant therapies in patients with MFS were included. Statistical analysis and creation of hazard ratios were performed using Revman 5.3 (Cochrane Collaboration).

RESULTS

We identified 301 studies, 10 of which were included in the final analysis. Neither chemotherapy nor radiation affected the rate of LR (p = 0.73 and 0.17, respectively) or OS (p = 0.97 and 0.27, respectively). Chemotherapy was significantly associated with lower rates of DM (p = 0.03); however, there was no association between radiation and DM (p = 0.67).

CONCLUSION

There is a lack of consensus regarding the effect of neoadjuvant and adjuvant therapies on LR, DM, and OS in patients with MFS. Our systematic review found that radiation and chemotherapy were not significantly associated with OS or LR in patients with MFS. However, we identified a significant association between chemotherapy and lower rates of DM.

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.

An aggressive soft-tissue sarcoma of the extremity: A myxofibrosarcoma, grade 3 (FNCLCC system)

We report a case of myxofibrosarcoma of the posterior region of the femur, part of the group of soft-tissue sarcomas: a set of rare and heterogeneous tumors with various subtypes and different prognostic. It is characterized by local infiltrative activity and an extremely high rate of local recurrence. A 58-year-old man came to the Radiology Department to examine a voluminous round and expansive formation of the posterior thigh region. The patient stated that the mass had grown suddenly for about 3 months, maybe after a trauma, increasing in volume exponentially and causing him discomfort, embarrassment, and pain. The result of the first diagnostic approach, with the US, was unexpected and suspicious, and the radiologist wanted to do first a CT, and then maybe plan an MRI. The CT revealed an inhomogeneous density formation and in MRI the mass resulted to be compatible, with the radiologic pattern, with the diagnosis of a sarcoma of the soft tissue. The physicians had already alerted the pathological anatomy, as they suspected something malignant. So, some days after the MRI examination, the patient underwent histological sampling, confirming the suspicion: a myxofibrosarcoma (stage III) of the posterior region of the femoral region. The patient started on radio and chemotherapy, which increases survival and in the hope of reducing the size of the mass, and a strict follow-up was posed before doing the surgery.

A pulmonary mass extending into the left atrium through the pulmonary vein: a rare diagnosis with an unusual origin

INTRODUCTION

Myxofibrosarcoma usually occurs in the extremities of middle-aged to older adults. Metastatic myxofibrosarcomas generally emerge in the lung. In this case report, we aim to present a case of primary pulmonary myxofibrosarcoma with tumor thrombus extending into the left atrium without pulmonary vein or atrial invasion.

CASE PRESENTATION

A 55-year-old male who was being followed up due to a pulmonary nodule presented with a mass extending from the left lower lobe to the left atrium. No extrathoracic malignancy was detected in the pre-operative examination. The mass extending into the left atrium without invasion was excised with the lower lobe of the left lung. A post-operative histopathological examination revealed myxofibrosarcoma.

CONCLUSION

Very few cases of cervical, thoracic wall, mediastinum and cardiac primary myxofibrosarcoma have been documented, and to the best of our knowledge, only one primary pulmonary myxofibrosarcoma case has previously been reported in the English literature. Here, we present a case of primary pulmonary myxofibrosarcoma that extended to the left atrium through the pulmonary vein. In such rare clinical presentations, intracardiac tumor resection should precede pulmonary resection due to the possibility of catastrophic tumor embolisms.

Orbital metastasis of myxofibrosarcoma

Myxofibrosarcoma (MFS), a common sarcoma in adults, typically affects the extremities. Primary orbital involvement is uncommon, and orbital metastasis is exceedingly rare. We describe a case of orbital MFS due to metastasis and provide an updated literature review. A 56-year-old woman presented with 2 months of progressive right eye proptosis. Relevant history included left palmar MFS excised 2 years prior. Examination demonstrated proptosis and restriction in abduction of her right eye without optic nerve compromise. Imaging revealed a well-circumscribed right orbital mass. Initial biopsy showed glandular tissue with chronic inflammation without an evidence of malignancy. She subsequently developed worsening proptosis, complete ophthalmoplegia, and a new afferent pupillary defect. Repeat orbital excisional biopsy with deeper dissection demonstrated high-grade MFS consistent with metastasis. She underwent chemoradiation with resolution of her lesion. Literature review identified 12 previously reported cases of MFS, only two of which involved metastasis to the orbit and were associated with worse prognosis. This report highlights a rare case of orbital metastasis of MFS with high-grade features confirmed on histopathology and provides an updated literature review. Prompt diagnosis and complete removal of MFS located both systemically and in the orbit are essential due to the metastatic potential.

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.

Myxofibrosarcoma: Outcomes, Prognostic Factors, and Role of Neoadjuvant Radiation Therapy

Purpose

Myxofibrosarcoma (MFS) is a subtype of soft tissue sarcoma with a highly infiltrative growth pattern that leads to a higher risk of inadvertent positive surgical margins and local relapse. Poorly defined tumor margins also pose a challenge for radiation therapy (RT) planning, in terms of treatment volumes and administration of pre- versus postoperative RT. This study aims to evaluate local control and patterns of recurrence in patients with MFS treated with neoadjuvant RT followed by definitive surgical excision.

Methods and Materials

Multiple institutional databases were retrospectively searched for patients diagnosed with MFS between 2013 and 2021 who were exclusively treated with preoperative RT followed by definitive surgery at our institution. The endpoints of the study were defined as local tumor recurrence, distant metastasis, and death after the date of definitive surgery.

Results

Forty-nine patients met the inclusion criteria and were included in the final study. The median age at diagnosis was 67 years, and 71% of patients were male. The tumor was superficially located in 63% of patients, and the mean tumor size at presentation was 7.8 cm. All patients received neoadjuvant RT and completed their planned course of treatment. Neoadjuvant chemotherapy was administered in 22% of patients. Inadvertent excision (IE) before definitive treatment was performed in 25 patients (51%), 84% of which had superficially located tumors. All margins were assessed using frozen section analysis at the time of definitive surgery, and 100% of patients had negative surgical margins, with 25% having no residual tumor. With a median follow-up of 4.7 years, the 5-year local control rate was 87%, and 5-year overall survival was 98%. Tumor depth was associated with distant metastasis (P < .01).

Conclusions

Despite the infiltrative nature of MFS, preoperative RT followed by definitive surgical excision, especially in the setting of a reliable frozen section margin analysis, was associated with excellent local control.

Clear surgical margins as a prognostic indicator for disease recurrence, with no impact on survival rates in patients with myxofibrosarcoma

Myxofibrosarcoma presents an infiltrating growth pattern that results in a high tendency for local recurrence. Clear margin resection is challenging because of microscopic infiltration. The purpose of the present study was to analyze the overall and disease-free survival rates of patients with myxofibrosarcoma and the prognostic factors that determine both survival and disease recurrence. Among the 111 patients included in our study, the 5-year overall survival rate was 65.5%. An age of more than 65 years (hazard ratio [HR] 1.9 [95% confidence interval (CI) 1.4-5.6]; p < 0.001), a tumor size of more than 5 cm (HR 2.8 [95% CI 0.9-8.1]; p = 0.049) and the G3 tumor grade (HR 14.1 [95% CI 2.1-105.0]; p < 0.001) negatively affected overall survival. The 5-year recurrence-free survival rate was 49.4%. R1/R2-type resection (HR 2.4 [95% CI 1.0-5.6]; p = 0.048) had a detrimental effect on tumor recurrence. Clear margins had a positive impact on recurrence-free survival, but did not significantly affect overall patient survival, suggesting that other factors may play a more significant role in determining patient outcomes. A surgical margin of 2 mm was not sufficient to significantly influence the incidence of recurrence. Consequently, a wider surgical margin may be necessary to reduce the risk of myxofibrosarcoma recurrence.

Epidemiology and survival factors of appendicular myxofibrosarcoma: a SEER-retrospective study

Background

The low incidence of myxofibrosarcoma (MFS) makes high power studies difficult to perform. Demographic and prognostic factors for MFS and how they differ from all extremity soft tissue sarcomas (STS) are not well understood. The purpose of this study was to characterize a large cohort of patients with MFS and evaluate epidemiologic and survival factors when compared to all STS.

Materials and methods

We performed a retrospective review of the Surveillance, Epidemiology, and End Results (SEER) database from 2000 to 2015 to identify 1,440 patients diagnosed with MFS and 12,324 with STS. Survival curves were creased using Kaplan-Meier, and Cox regression analyses were performed to identify hazard ratios (HRs).

Results

Overall survival was greater for STS than MFS (79% vs. 67%). Patients with MFS had a higher average age at diagnosis than STS (62 vs. 56), and older age was strongly associated with decreased survivorship for MFS (HR = 7.94). A greater proportion of patients under 30 diagnosed with MFS were female when compared to STS (49.6% vs. 45.4%). The incidence of MFS and STS increased over the 15-year period, with MFS increasing at a greater rate than STS (1.25% vs. 2.59%). Survival increased for patients diagnosed after 2008 for both STS (9.4%) and MFS (13.2%).

Conclusions

There are differences between patient demographics and survival factors when comparing MFS to all STS. Monitoring changes in demographic and survival trends for rare STS subtypes like MFS is important to improve diagnostic algorithms and treatment options.

Analysis of clinical factors impacting recurrence in myxofibrosarcoma

Myxofibrosarcoma (MFS) is a malignant fibroblastic/myofibroblastic neoplasm with a prominent myxoid area. It has the clinical features of frequent local recurrence (LR) and occasional distant metastasis. Robust epidemiological data on MFS in China are lacking. The aim of this retrospective analysis was to determine the natural history of MFS, identify prognostic factors for recurrence and describe the real-life outcomes of MFS. We reviewed 52 patients with primary MFS from the First Affiliated Hospital of Nanjing Medical University diagnosed between 2016 and 2020. All tumors were subjected to retrospective univariate analysis for prognostic factors of the disease, including tumor size, grade, location and sex; patient age; planned operation; surgical margin; and laboratory results. The significant factors identified by univariate analysis were subsequently analyzed via multivariate analysis. Overall survival (OS), post-treatment LR and metastatic-free survival were assessed as outcomes. The median age was 61 years (range, 13-93). Fourteen (26.92%) patients exhibited low grade disease, and 38 (73.08%) exhibited high grade disease. Among the 29 males, and 23 females, 15 (28.85%) had tumors in the trunk, 37 (71.15%) had tumors in the extremities, 26 had undergone planned surgery, and 26 had unexpected unplanned operation. The margin was negative in 39 (75%) patients and positive in 13 patients (25%). The serum creatine kinase (CK) concentration was high level in 33 (63.46%) patients and low level in 19 (36.54%) patients. The serum lactate dehydrogenase (LDH) levels were low in 23 (44.23%) patients and high in 29 (55.77%) patients. LR was observed in 25 patients (48.08%), and 4 patients developed metastasis. A worse LR rate was found for patients with a low CK level (84.21%) than for those with a high CK level (27.27%) at 5 years (p < 0.05). The LR rate of patients who underwent planned surgery was lower than that of patients who underwent unplanned surgery (p < 0.05). There were significantly more patients with positive margins than patients with negative margins (92.30%, and 33.33%, respectively; p < 0.05). Moreover, superficial tumors were also associated with greater recurrence rate (2/20 [10%]) than deep tumors, (23/32 [71.86%]) [p < 0.05]. The probability of LR in patients with MFS was significantly greater in association with unplanned operations, positive margins, low serum CK levels or superficial tumor depth. These data could help identify high-risk patients; thus, more careful follow-up should be performed for higher-risk patients. Diagnosis and treatment at qualified regular medical centers can reduce the local recurrence rate of MFS.

Myxofibrosarcoma in adolescents and young adults: a clinicopathologic study of 17 cases

Myxofibrosarcoma is a locally aggressive sarcoma that characteristically arises in the extremities of older patients. Cases arising at a younger age are rare, leading to diagnostic challenges. Our aim was to study the clinicopathologic features of myxofibrosarcoma in patients aged ≤40 years. Cases of myxofibrosarcoma and myxoid malignant fibrous histiocytoma arising in patients aged ≤40 years with clinical follow-up were collected from multiple institutions. Hematoxylin and eosin slides were evaluated for mitoses, necrosis, and epithelioid areas. Seventeen cases were identified (13 females, 4 males; 16-39 years; median 32 years), tumors ranged from 2.2 to 34 cm (median 4.1 cm). Anatomic sites included proximal extremity (9), distal extremity (4), trunk (1), and head/neck (3). Ten were superficial, and 6 were deep-seated. Three cases were predominantly epithelioid. In untreated resection specimens, 6 were FNCLCC grade 1, 4 grade 2, and 2 grade 3. Follow-up (6-204 months, median 36 months) revealed that 2 patients experienced local recurrences, 1 distant metastasis, and 2 patients both. The 5-year overall survival (OS) and event-free survival (EFS) were 84% and 55.9%, respectively. Tumor depth and necrosis were correlated with inferior OS (P = .025, P = .005), while tumor depth was also associated with worse EFS (P = <.001). We conclude that myxofibrosarcomas arising in adolescents and young adults show similar behavior compared to their older adult counterparts. Tumor depth and necrosis are poor prognostic factors in myxofibrosarcoma in this age group. Awareness that myxofibrosarcoma can rarely present in this population is important for accurate diagnosis.

Mediastinal Myxofibrosarcoma Harboring Loss-of-Function MSH2 Variant in a Patient With Lynch Syndrome: A Case Report and Literature Review

Myxofibrosarcoma is a malignant fibroblastic neoplasm that commonly arises in the extremities, with mediastinum being a very rare location. The development of sarcomas is uncommon in patients with Lynch syndrome. We present a Lynch syndrome patient with synchronous cecal adenocarcinoma and mediastinal myxofibrosarcoma with both harboring the same loss-of-function MSH2 alteration (c.2634 + 1G > A splice region variant). Metastatic myxofibrosarcoma in the left chest wall developed 6 months after the initial diagnosis. The clinical presentation, imaging findings, histopathology, and molecular studies along with differential diagnoses are presented and discussed.

Is the Thickness of the Margin Associated With Local Recurrence and Survival in Patients With Myxofibrosarcoma?

BACKGROUND

Myxofibrosarcoma (MFS) is a spectrum of aggressive soft tissue fibroblastic neoplasms characterized by variable myxoid stroma, pleomorphism, and a distinctive curved vascular pattern; these tumors are associated with a high likelihood of recurrence. Better local tumor control (a tumor-free margin) is believed to be important to minimize the risk of recurrence, but the effect of surgical resection margin status on local recurrence and survival in MFS is not as well-characterized as it might be.

QUESTIONS/PURPOSES

(1) Is margin width associated with local recurrence? (2) Is there a relationship between greater margin thickness and improved overall and disease-free survival (DFS)? (3) Is worsening French Federation of Cancer Centers grade associated with local recurrence and poorer overall survival?

METHODS

Using a database of patients with bone and soft tissue tumors at a tertiary university hospital, we retrospectively reviewed the medical records of 282 patients who had soft tissue sarcomas and who had been surgically treated by a multidisciplinary bone and soft tissue tumor care team between January 2010 and December 2021. Of these 282 patients, 38 were identified as having MFS. Patients who received surgical care for MFS outside our institution (unplanned resection) (four patients) and whose surgical margins were not reported as microscopic numerical data (10) were excluded from the analysis. We estimated survival and local recurrence and examined factors potentially influencing these outcomes. Patient demographics, tumor characteristics, surgical margin distance (in mm), and disease-related outcomes were recorded. The minimum follow-up was 3 months (median 41.5 months, range 3 to 128 months).

RESULTS

Overall 1-year local recurrence-free rates were 66.7% (95% CI 50% to 88%). Patients with positive margins were more likely to have local recurrence than patients with negative margins (HR 10.91 [95% CI 2.61 to 45.66]; p = 0.001). Patients with an inadequate margin (positive margin or a negative margin of 1 mm or less) had a greater risk of local recurrence (HR 9.96 [95% CI 1.22 to 81.44]; p = 0.032). Patients with positive margins or margins less than or equal to 1 mm had worse 2-year local recurrence-free survival than did those with margins of greater than 1 mm (46.9% [95% CI 16% to 76%] versus 91.7% [95% CI 75% to 100%]; p = 0.005). The mean overall survival was 98 months (95% CI 77.2 to 118.8). The Kaplan-Meier overall 1-, 2- and 5-year estimated rates of survival were 88% (95% CI 75% to 100%), 79.2% (95% CI 64.5% to 97.2%), and 73.5% (95% CI 57.2 % to 94.5%), respectively. Positive surgical margins were associated with decreased overall survival (HR 6.96 [95% CI 1.39 to 34.89]; p = 0.018). There was a mean DFS time of 4.25 months (95% CI 0.92 to 7.59) in microscopically positive patients, 75.5 months (95% CI 37.47 to 113.53) in patients with margins 1 mm or less, and 118 months (95% CI 99.23 to 136.77) in patients with margins over 1 mm. There was a statistical difference between DFS times according to surgical margin classification (p < 0.001). With the numbers we had, we could not detect any difference between the histologic grades determined by the French Federation of Cancer Centers grading system in terms of local recurrence (HR 3.80 [95% CI 0.76 to 18.94]; p = 0.103) and overall survival (HR 6.91 [95% CI 0.79 to 60.13]; p = 0.080). Tumor size was the prognostic factor associated with a higher local recurrence rate among all factors analyzed as univariate (HR 1.18 [95% CI 1.05 to 1.32]; p = 0.004).

CONCLUSION

A surgical procedure with a sufficient negative surgical margin distance appears to be associated with a lower proportion of patients who experience a local recurrence and is associated with overall patient survival. It is difficult to define what a sufficient margin is, but in our patients, it appears to be greater than 1 mm.Level of Evidence Level III, therapeutic study.

Modeling Myxofibrosarcoma: Where Do We Stand and What Is Missing?

Myxofibrosarcoma (MFS) is a malignant soft tissue sarcoma (STS) that originates in the body's connective tissues. It is characterized by the presence of myxoid (gel-like) and fibrous components and typically affects patients after the fifth decade of life. Considering the ongoing trend of increasing lifespans across many nations, MFS is likely to become the most common musculoskeletal sarcoma in the future. Although MFS patients have a lower risk of developing distant metastases compared with other STS cases, MFS is characterized by a high frequency of local recurrence. Notably, in 40-60% of the patients where the tumor recurs, it does so multiple times. Consequently, patients may undergo multiple local surgeries, removing the risk of potential amputation. Furthermore, because the tumor relapses generally have a higher grade, they exhibit a decreased response to radio and chemotherapy and an increased tendency to form metastases. Thus, a better understanding of MFS is required, and improved therapeutic options must be developed. Historically, preclinical models for other types of tumors have been instrumental in obtaining a better understanding of tumor development and in testing new therapeutic approaches. However, few MFS models are currently available. In this review, we will describe the MFS models available and will provide insights into the advantages and constraints of each model.

Heart Transplantation as a Treatment Option for Recurrent Myxofibrosarcoma: A Clinical Case

Myxofibrosarcoma is one of the most rare tumors of the heart. Surgical resection is the principal method of treatment; however, in some cases, radical removal of the tumor is not possible. Here, we present a case of heart transplant in a patient who experienced recurrent myxofibrosarcoma of the left atrium and examine the morphological features of this tumor. A 40-year-old female patient presented for treatment for heart failure of a high functional class. An examination revealed a tumor in the left atrial cavity, which was subsequently surgically removed. Morphological examination revealed an inflammatory myofibroblastic tumor. After 2 years, the patient's tumor recurred. The tumor was removed, and a morphological study again diagnosed myxofibrosarcoma of the heart. A year later, recurrence was again diagnosed. Instrumental examination determined that the tumor had incurred into the mitral valve and possibly spread to the myocardium. Tumor resection was not possible, and the need to perform a heart transplant was determined. The given case contributes to the practical conclusion that heart transplant contributes to an increase in the life expectancy for patients with inoperable cases of cardiac sarcoma.

Fibroblast Activation Protein Expression in Sarcomas

Objectives

Fibroblast activation protein alpha (FAP) is highly expressed by cancer-associated fibroblasts in multiple epithelial cancers. The aim of this study was to characterize FAP expression in sarcomas to explore its potential utility as a diagnostic and therapeutic target and prognostic biomarker in sarcomas.

Methods

Available tissue samples from patients with bone or soft tissue tumors were identified at the University of California, Los Angeles. FAP expression was evaluated via immunohistochemistry (IHC) in tumor samples (n = 63), adjacent normal tissues (n = 30), and positive controls (n = 2) using semiquantitative systems for intensity (0 = negative; 1 = weak; 2 = moderate; and 3 = strong) and density (none, <25%, 25-75%; >75%) in stromal and tumor/nonstromal cells and using a qualitative overall score (not detected, low, medium, and high). Additionally, RNA sequencing data in publicly available databases were utilized to compare FAP expression in samples (n = 10,626) from various cancer types and evaluate the association between FAP expression and overall survival (OS) in sarcoma (n = 168).

Results

The majority of tumor samples had FAP IHC intensity scores ≥2 and density scores ≥25% for stromal cells (77.7%) and tumor cells (50.7%). All desmoid fibromatosis, myxofibrosarcoma, solitary fibrous tumor, and undifferentiated pleomorphic sarcoma samples had medium or high FAP overall scores. Sarcomas were among cancer types with the highest mean FAP expression by RNA sequencing. There was no significant difference in OS in patients with sarcoma with low versus high FAP expression.

Conclusion

The majority of the sarcoma samples showed FAP expression by both stromal and tumor/nonstromal cells. Further investigation of FAP as a potential diagnostic and therapeutic target in sarcomas is warranted.

The Prognostic Relevance of MRI Characteristics in Myxofibrosarcoma Patients Treated with Neoadjuvant Radiotherapy

To improve local control, neoadjuvant radiotherapy (nRT) followed by surgery is the standard of care in myxofibrosarcoma (MFS) because of its infiltrative growth pattern. Nevertheless, local recurrence rates are high. Data on prognostic factors for poor clinical outcomes are lacking. This retrospective study thus investigates the prognostic relevance of magnetic resonance imaging (MRI) characteristics before and after nRT in 40 MFS patients, as well as their association with disease-free survival (DFS) and overall survival (OS). A vascular pedicle, defined as extra-tumoral vessels at the tumor periphery, was observed in 12 patients (30.0%) pre-nRT and remained present post-nRT in all cases. Patients with a vascular pedicle had worse DFS (HR 5.85; 95% CI 1.56-21.90; p = 0.009) and OS (HR 9.58; 95% CI 1.91-48.00; p = 0.006). An infiltrative growth pattern, referred to as a tail sign, was observed in 22 patients (55.0%) pre-nRT and in 19 patients (47.5%) post-nRT, and was associated with worse DFS post-nRT (HR 6.99; 95% CI 1.39-35.35; p = 0.019). The percentage of tumor necrosis estimated by MRI was increased post-nRT, but was not associated with survival outcomes. The presence of a tail sign or vascular pedicle on MRI could support the identification of patients at risk for poor clinical outcomes after nRT.

Cathepsin protease expression in infiltrative soft tissue sarcomas: cathepsin-K correlates with infiltrative tumor growth and clinical outcomes

Cathepsin proteases, activated in the lysosomes, are upregulated in many cancers. Intraoperative detection systems of microscopic residual tumor using cathepsin-mediated release of fluorescent nanoparticles may guide surgical excisions to improve local control. We sought to define the genetic and proteomic expression of cathepsins and their clinicopathological correlates in myxofibrosarcoma and undifferentiated pleomorphic sarcoma (UPS)-soft tissue sarcomas with high rates of positive resection margins and local recurrence-and to establish a cellular justification for cathepsin-dependent systems to identify residual cancer in the resection bed. Real-time quantitative polymerase chain reaction analysis of 58 fresh-frozen tumor specimens revealed that 56 (97%) had elevated mRNA expression of ≥1 cathepsin, including cathepsin-B (79%), cathepsin-K (59%), cathepsin-L (71%), and -S (71%). Immunohistochemical analysis of these fresh-frozen specimens revealed that 98% of tumors were positive for one or more of cathepsin-B (85%), cathepsin-K (50%), cathepsin-L (63%), and -S (10%). Strong cathepsin-K expression was associated with greater risks of local recurrence (hazard ratio, 3.78; p = 0.044) and disease-specific mortality (hazard ratio, 3.70; p = 0.025). Immunohistochemical analysis of 33 formalin-fixed paraffin-embedded block samples revealed that 97% were positive for cathepsin-B (88%), cathepsin-K (76%), cathepsin-L (52%), or -S (52%) at the tumor periphery; cathepsin-K positivity correlated with a radiographic tail-like sign (p = 0.004) and microscopic infiltrative growth (p = 0.020). We conclude that cathepsins are broadly overexpressed in myxofibrosarcoma and UPS, and cathepsin-K may be an immunohistochemical marker of local infiltration and poorer prognosis that could be used to guide precision surgery.

Immunohistochemical Evaluation of Candidate Biomarkers for Fluorescence-Guided Surgery of Myxofibrosarcoma Using an Objective Scoring Method

INTRODUCTION

Myxofibrosarcoma (MFS) is the most common soft-tissue sarcoma subtype in elderly patients. Local recurrence (LR) remains a major concern as the lack of intraoperative guidance and an infiltrative growth pattern with long, slender tails hamper surgeons' ability to achieve adequate resection margins for MFS. Fluorescence-guided surgery (FGS) could overcome this concern by delineating tumor tissue during surgery. One of the most important steps to successful FGS is to define a tumor-specific biomarker that is highly overexpressed in tumor tissue while low or absent in adjacent healthy tissue. The aim of this study is to evaluate the expression of eight previously selected promising biomarkers for FGS in MFS tissue samples with adjacent healthy tissue using immunohistochemistry (IHC).

METHODS

The following eight biomarkers were stained in seventeen paraffin-embedded MFS samples: tumor endothelial marker-1 (TEM-1, also known as endosialin/CD248), vascular endothelial growth factor receptor-1 (VEGFR-1, also known as Flt-1), vascular endothelial growth factor receptor-2 (VEGFR-2, also known as Flk1), vascular endothelial growth factor-A (VEGF-A), epidermal growth factor receptor (EGFR), insulin-like growth factor-1 receptor (IGF-1R), platelet derived growth factor receptor-α (PDGFR-α), and cluster of differentiation 40 (CD40, also known as TNFRSF5). A pathologist specializing in sarcoma annotated the margin between the tumor and adjacent healthy tissue in each MFS tissue sample. Subsequently, we used an objective IHC scoring method to assess and compare the difference in staining intensity between the tumor and adjacent healthy tissue, which is crucial for the use of FGS.

RESULTS

TEM-1, VEGF-A, and PDGFR-α stained all MFS tumors, while the other biomarkers did not show expression in all MFS tumors. Ultimately, TEM-1 was identified as the most suitable biomarker for FGS in MFS based on higher tumor-to-background (TBR) staining intensity compared to VEGF-A and PDGFR-α, regardless of preoperative therapy.

CONCLUSION

TEM-1-targeted FGS tracers should be further investigated to optimize MFS treatment.

Exosome-Based Liquid Biopsy Approaches in Bone and Soft Tissue Sarcomas: Review of the Literature, Prospectives, and Hopes for Clinical Application

The knowledge of exosome impact on sarcoma development and progression has been implemented in preclinical studies thanks to technological advances in exosome isolation. Moreover, the clinical relevance of liquid biopsy is well established in early diagnosis, prognosis prediction, tumor burden assessment, therapeutic responsiveness, and recurrence monitoring of tumors. In this review, we aimed to comprehensively summarize the existing literature pointing out the clinical relevance of detecting exosomes in liquid biopsy from sarcoma patients. Presently, the clinical utility of liquid biopsy based on exosomes in patients affected by sarcoma is under debate. The present manuscript collects evidence on the clinical impact of exosome detection in circulation of sarcoma patients. The majority of these data are not conclusive and the relevance of liquid biopsy-based approaches in some types of sarcoma is still insufficient. Nevertheless, the utility of circulating exosomes in precision medicine clearly emerged and further validation in larger and homogeneous cohorts of sarcoma patients is clearly needed, requiring collaborative projects between clinicians and translational researchers for these rare cancers.

Oncologic outcomes in myxofibrosarcomas: the role of a multidisciplinary approach and surgical resection margins

BACKGROUNDS

Myxofibrosarcomas (MFS) are malignant soft tissue sarcomas with an infiltrative growth pattern and propensity for local recurrence(LR).We aimed to assess our management of MFS and make recommendations about the role of a multidisciplinary team approach and margin widths.

METHODS

Fifty-seven patients were identified with MFS treated at a single sarcoma centre between 1998 and 2020. Patients were stratified based on whether they presented for a planned resection (59.6%) or after an unplanned resection (40.4%) performed at a non-specialized facility. All patients underwent radiotherapy before definitive surgery.

RESULTS

73.7% underwent a combined onco-plastic approach. The 5 year LRFS rate was 78.2% (84.4%, planned, versus 70.1%, unplanned, P = 0.194) and found comparable oncological outcomes between the planned and unplanned groups for the 5 year metastasis free survival (74.5% versus 86.1%, P = 0.257), disease free survival (70.1% versus 72.4%, P = 0.677), and Overall Survival (64.5% versus 75.9%, P = 0.950). Margin width ≥ 2 cm was obtained in 84.2% of cases and improved local control (HR = 0.22; 95% CI 0.06-0.81; P = 0.023), metastasis (HR = 0.24; 95% CI 0.07-0.80; P = 0.019) and mortality rates (HR = 0.23; 95% CI 0.09, 0.61; P = 0.003) compared to <2 cm. Margin width > 3 cm did not further affect oncological outcomes.

CONCLUSION

Our study shows that a multidisciplinary team approach allows the achievement of low local recurrence rate and good oncological outcomes of myxofibrosarcomas, regardless of presentation status. We recommend a minimum of 2 cm margin width.

[Myxosarcoma in the cervical region in a teddy bear hamster (Mesocricetus auratus)]

This case report describes a rare case of a myxosarcoma in a 1-year-old teddy bear hamster presenting with a mass in the cervical region. The fine-needle aspiration cytology revealed high numbers of pleomorphic spindle-shaped cells found in a viscous mucinous background. The presumptive cytological diagnosis was malignant spindle cell neoplasia based on marked criteria of malignancy of the mesenchymal cell population. The abundant matrix in the background was suggestive of a myxosarcoma. The hamster died during surgery and a necropsy was performed. Histopathology was in complete agreement with the cytological report. Immunohistochemistry revealed the tumour to be vimentin positive with alcian-blue positive matrix and confirmed the presumptive diagnosis of a myxosarcoma. This case shows that fine-needle aspiration cytology can be utilized as a minimally invasive diagnostic tool in small mammals to classify mass lesions. However, so far little is known about the biological behaviour of myxosarcoma in the hamster as case descriptions are rare.

A combined, supraclavicular, infraclavicular, transaxillary, and posterior subscapular approaches for en bloc resection of giant myxofibrosarcoma

Background

Myxofibrosarcoma (MFS) is a rare and locally infiltrative tumor that commonly occurs in extremities in older adults; however, truncal and head and neck cases have been reported. They are characterized by multinodular growth, incomplete fibrous septa, and myxoid stroma. Surgical resection is the mainstay of treatment.

Case Description

The authors report a case of a combined, supraclavicular, infraclavicular, transaxillary, and posterior subscapular approaches for resection of giant MFS.

Conclusion

The anatomical complexity and rarity of tumors involving the brachial plexus impose many challenges onto surgeons performing surgical resections. Treatment choices and surgical outcomes rely heavily on meticulous multidisciplinary planning, anatomical knowledge, careful dissection, and extent of resection. This case is unique in utilizing four different approaches to the brachial plexus to resect one tumor.

Primary thyroid gland myxofibrosarcoma: a case report and review of the literature

Background

Myxofibrosarcoma is a common soft tissue sarcoma of the extremities, which occurs very rarely in the thyroid gland.

Case presentation

We report the case of a 61-year-old male who presented with a swelling of the left side of the neck and a newly emerged hoarseness. Ultrasound depicted a hypoechoic thyroid nodule with microcalcifications that was highly suspicious for malignancy. He underwent a left hemithyroidectomy. Histopathological examination and immunohistochemical studies revealed a myxofibrosarcoma of the thyroid gland.

Conclusion

Myxofibrosarcoma of the thyroid gland is extremely rare. The diagnosis is based on histopathological features. Radical surgery achieving tumor-free resection margins remains the only chance for cure. However, the role of radiotherapy and/or chemotherapy is still under debate. Due to their high tendency for locoregional recurrence, a close follow-up after surgery is mandatory.

Epidemiologic Survey of Myxofibrosarcoma Using Data from the Bone and Soft Tissue Tumor Registry in Japan

BACKGROUND

Myxofibrosarcoma is a common sarcoma among older patients, with locally infiltrative behavior and a predilection for local postoperative recurrence. Some studies have reported the factors affecting prognosis, although only a few have mentioned the previous staging classification systems. This study investigated the clinical overview and prognosis of myxofibrosarcoma to determine the optimal treatment.

METHODS

This retrospective study analyzed the records of 349 patients with myxofibrosarcoma in the nationwide Bone and Soft Tissue Tumor Registry in Japan from 2006 to 2015. Clinical features, treatment options, and patient outcomes were investigated.

RESULTS

Ultimately, 349 patients were identified. The overall survival rates were 93.1% at 2 years and 84.3% at 5 years. A multivariate analysis was performed using the Cox proportional hazards model. The study identified four significant prognostic factors for survival: tumor size, depth, compartment status, and location. The prognostic score was calculated by summing the scores of all the factors. The overall survival rate was 69.3% at 5 years for the patients with prognostic scores of 6 or higher. Conversely, the patients with prognostic scores of 2 or lower had a survival rate of 95.6% at 5 years.

CONCLUSIONS

Among myxofibrosarcomas, those larger than 5 cm, deep-seated, invaded into the external compartment, or in axial body parts were associated with a significantly worse prognosis. Adjuvant radiotherapy and chemotherapy did not contribute significantly to a better prognosis. Previous staging classification systems are impractical for prognosis prediction. Therefore, new classifications are needed. Further research on new treatment methods for patients with a poor prognosis will be crucial in the future.

Head‑to‑head assessment of [68Ga]Ga-DOTA-FAPI-04 PET/CT vs [18F]FDG PET/CT in fibroblastic tumors

OBJECTIVES

We aimed to evaluate [⁶⁸Ga]Ga-DOTA-FAPI-04 versus [¹⁸F]FDG PET/CT in the application of fibroblastic tumors.

METHODS

Twenty participants with 6 subtypes of fibroblastic tumors prospectively underwent ¹⁸F-FDG and [⁶⁸Ga]Ga-DOTA-FAPI-04 PET/CT examinations to evaluate the lesions. PET/CT findings were confirmed by surgical pathology of fifteen participants, puncture biopsy of two participants, or imaging follow-up of three participants. Two independent sample t tests were used to compare the uptake of [¹⁸F]FDG vs [⁶⁸Ga]Ga-DOTA-FAPI-04 in primary, recurrent and metastatic lesions. One-way ANOVA was used to compare the uptake of [¹⁸F]FDG or [⁶⁸Ga]Ga-DOTA-FAPI-04 among primary, recurrent, and metastatic lesions. The uptake of [⁶⁸Ga]Ga-DOTA-FAPI-04 vs [¹⁸F]FDG in different histopathological lesions was compared by two independent sample t tests.

RESULTS

Twenty participants were confirmed to have 38 lesions. Although there was no significant difference in the detection of lesions between [⁶⁸Ga]Ga-DOTA-FAPI-04 and [¹⁸F]FDG PET/CT (38 vs 36, p = 0.493), the uptake of [⁶⁸Ga]Ga-DOTA-FAPI-04 in lesions was significantly higher than that of [¹⁸F]FDG (p < 0.001), including primary (p < 0.001), recurrent (p = 0.018) and metastatic (p < 0.001) lesions. The SUVmax of [⁶⁸Ga]Ga-DOTA-FAPI-04 in primary and recurrent lesions was higher than that in metastasis (p = 0.034 and p = 0.015, respectively). The SUVmax of [⁶⁸Ga]Ga-DOTA-FAPI-04 in primary and recurrent malignant lesions was significantly higher than that of the intermediate (p < 0.001). The SUVmax of [⁶⁸Ga]Ga-DOTA-FAPI-04 in one participant of recurrent SFT with 5 lesions was significantly lower after treatment than before treatment (p = 0.016).

CONCLUSIONS

[⁶⁸Ga]Ga-DOTA-FAPI-04 outperformed [¹⁸F]FDG PET/CT in displaying the primary, recurrent and metastatic lesions of fibroblastic tumors.

Establishment and characterization of NCC-MFS6-C1: a novel patient-derived cell line of myxofibrosarcoma

Myxofibrosarcoma (MFS) is a rare and aggressive mesenchymal malignancy characterized by complex karyotypes with heterogeneous clinical features. The standard treatment for primary MFS is curative resection; however, the utility of systemic chemotherapy and radiotherapy has not been established. Although patient-derived cancer cell lines are a key bioresource for developing novel therapies, the number of MFS cell lines available from public cell banks is limited by the rarity of the disease, and large-scale drug screening has not yet been performed. To address this issue, we aimed to establish and characterize a novel MFS cell line. We successfully established a cell line, NCC-MFS6-C1, which harbors genetic abnormalities common in MFS and exhibits aggressive phenotypes such as continuous growth, spheroid formation, and invasion in tissue culture conditions. We performed drug screening using NCC-MFS6-C1 along with five MFS cell lines established in our laboratory and clarified the response spectrum of 214 existing anticancer agents. We found that two anticancer agents, gemcitabine and romidepsin, showed considerable antiproliferative effects, and these observations were concordant with the findings of our previous report, in which these agents attenuated the proliferation of five previously reported MFS cell lines. We conclude that NCC-MFS6-C1 is a useful resource for studying MFS.

TIMP3::ALK fusions characterize a distinctive myxoid fibroblastic tumor of the vocal cords: a report of 7 cases

We report 7 cases of an indolent, variably myxoid tumor of the vocal cords, characterized by overt cellular atypia with large cells containing intranuclear and intracytoplasmic vacuoles, delicate curvilinear vessels, and sparse inflammatory infiltrate. Six patients were male, aged 15 to 65 years, and 1 patient was a 54-year-old female. All tumors were located in the superficial portion of the vocal cord. One patient suffered a recurrence that was completely resected; all patients with available follow-up data currently have no evidence of disease. The tumors contained alternating areas with myxoid stroma and more compacted regions with tumor cells organized in short fascicles, interwoven with delicate curvilinear vasculature. Overt cellular atypia with large cells containing intranuclear and intracytoplasmic vacuoles or resembling ganglion cells was present in all cases but mitoses and necrosis were absent. ALK immunostaining was positive in all cases, while most tumors were negative for smooth muscle actin. Targeted RNA-sequencing revealed an identical TIMP3::ALK fusion with exon 1 of TIMP3 gene being fused with exon 12 of ALK gene in all analyzable cases. For various reasons discussed, it remains unclear whether this tumor represents a mere subtype of IMT or a separate entity. Nevertheless, it is a morphologically distinct and diagnostically challenging lesion that needs to be recognized by surgical pathologists in order to prevent overdiagnosis in this clinically very delicate area.

Myxofibrosarcoma landscape: diagnostic pitfalls, clinical management and future perspectives

Myxofibrosarcoma (MFS) is a common entity of adult soft tissue sarcomas (STS) characterized by a predilection of the extremities and a high local recurrence rate. Originally classified as a myxoid variant of malignant fibrous histiocytoma, this musculoskeletal tumor has been recognized since 2002 as a distinct histotype showing a spectrum of malignant fibroblastic lesions with myxoid stroma, pleomorphism and curvilinear vessels. Currently, the molecular pathogenesis of MFS is still poorly understood and its genomic profile exhibits a complex karyotype with a number of aberrations including amplifications, deletions and loss of function. The diagnosis is challenging due to the unavailability of specific immunohistochemical markers and is based on the analysis of cytomorphologic features. The mainstay of treatment for localized disease is represented by surgical resection, with (neo)-adjuvant radio- and chemotherapy. In the metastatic setting, chemotherapy represents the backbone of treatments, however its role is still controversial and the outcome is very poor. Recent advent of genomic profiling, targeted therapies and larger enrollment of patients in translational and clinical studies, have improved the understanding of biological behavior and clinical outcome of such a disease. This review will provide an overview of current diagnostic pitfalls and clinical management of MFS. Finally, a look at future directions will be discussed.

Management of Myxofibrosarcoma and Undifferentiated Pleomorphic Sarcoma

Undifferentiated pleomorphic sarcoma (UPS) and myxofibrosarcoma (MFS) are genomically complex tumors commonly diagnosed in the extremities or trunk of elderly patients. They likely represent a spectrum of disease differentiated by myxoid stroma and curvilinear vessels observed in MFS but not in UPS. Limb-sparing surgery is the standard of care although the infiltrative nature of MFS mandates wider resection margins than are necessary for UPS. UPS are conversely associated with high risks of distal recurrence, often prompting recommendations for adjuvant chemotherapy. In both histologies, anthracycline-based therapies or gemcitabine and docetaxel are used to manage advanced disease; immunotherapy may be of benefit in a subset of patients.

Molecular and clinicopathological analysis revealed an immuno-checkpoint inhibitor as a potential therapeutic target in a subset of high-grade myxofibrosarcoma

This study aimed to identify differences in genetic alterations between low- and high-grade lesions in myxofibrosarcoma (MFS) and to examine the efficacy of immune checkpoint inhibitors in 45 patients with MFS. First, genetic differences between low- and high-grade components within the same tumor were analyzed in 11 cases using next-generation sequencing. Based on the obtained data, Sanger sequencing was performed for TP53 mutations in the remaining 34 patients. Loss of heterozygosity (LOH) analysis was performed at the TP53 and RB1 loci. Immunohistochemistry was performed for FGFR3, KIT, MET, programmed death receptor ligand 1 (PD-L1), CD8, FOXP3, and mismatch repair proteins. The microsatellite instability status was also evaluated in all cases. TP53 deleterious mutations and LOH at TP53 and RB1 loci were detected significantly more frequently in high-grade than in low-grade MFS (P = 0.0423, 0.0455, and 0.0455, respectively). LOH at the RB1 locus was significantly associated with shorter recurrence-free survival in both univariate and multivariate analyses. TP53 alterations, such as mutation and LOH, were more frequently observed in low-grade areas within high-grade MFS than in pure low-grade MFS. The positive PD-L1 expression rate was 35.6% (16/45), and all these 16 cases were high-grade. A high density of both CD8+ and FOXP3+ tumor-infiltrating lymphocytes was associated with PD-L1 positivity. LOH at the RB1 locus was identified an independent adverse prognostic factor for recurrence-free survival in patients with MFS. Immune checkpoint inhibitors may be a therapeutic option for a subset of high-grade MFS.

Myxofibrosarcoma of the abdominal wall : A case report and literature review

INTRODUCTION

Myxofibrosarcoma (MFS) is a subtype of soft tissue sarcoma characterized by diffuse infiltration patterns. Myxofibrosarcoma arises often in extremities. Its occurrence in the abdominal wall is extremely rare. Herein, we present here a case of high-grade MFS of the abdominal wall discovered in a 58-year-old woman complaining of an abdominal mass.

PRESENTATION OF CASE

This report illustrates the case of a female who presented a mass in the right lower quadrant of the abdomen. Abdominal computed tomography (CT) scan revealed a well-circumcised, heterogeneous soft tissue mass. We performed a wide margin excision of the mass. Histology concluded in myxofibrosarcoma of the abdominal wall. Adjuvant radiotherapy was performed.

CLINICAL DISCUSSION

We reported successful surgical treatment for myxofibrosarcoma of the abdominal wall. To our knowledge, this is the second report in English literature. MFS is a subtype of soft tissue sarcoma with a locally infiltrative behavior. To ensure the best curative treatment, It is important to excise the tumor with wide margins. Knowing that MFS has a propensity for local recurrence (16 to 57 %), adjuvant radiotherapy has emerged as an efficient treatment for improving local control. The role of chemotherapy is controversial and has not shown effects on survival.

CONCLUSION

Myxofibrosarcoma is a connective tissue neoplasm. Its occurrence in the abdominal wall is extremely rare. Surgical treatment with large negative margins is the cornerstone of the treatment. Adjuvant radiotherapy is essential in preventing local recurrences.

Case Report: Inguinal Myxofibrosarcoma Arising From the Surgical Site of Resected Squamous Cell Carcinoma

Myxofibrosarcoma (MFS) is a rare soft tissue sarcoma that originates in the mesenchymal tissue and occurs mainly in the limbs of elderly patients. Herein, we present the case of a 64-year-old woman who underwent extensive left vulvar resection and bilateral lymphadenectomy for vulvar squamous cell carcinoma 6 months previously. A mass was found again at the original surgical site of the left groin 3 months prior, and its size had increased significantly in the past 1 month, with ulceration and pus. Magnetic resonance imaging (MRI) showed a 10-cm mass in the left groin area; fluoro18-labeled deoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) showed a marked increase in mass metabolism in the left groin area, which was highly suspected to be a recurrence of squamous cell carcinoma. Subsequently, the patient underwent surgery and the postoperative pathology and immunohistochemistry confirmed MFS. In conclusion, MFS has rarely been reported to arise from the surgical site of squamous cell carcinoma. Our case study demonstrates that MFS should be included in the differential diagnosis of superficial masses in patients with a prior surgical history who present with a soft tissue mass at the surgical site, especially for recently developed rapidly increasing masses. This study aimed to systematically review the clinical features, diagnosis, differential diagnosis, treatment, and prognosis of this disease based on our case and related published literature and to provide clinicians with a broader perspective on the differential diagnosis of soft tissue tumors.

Clinicopathological Assessment of Cancer/Testis Antigens NY-ESO-1 and MAGE-A4 in Highly Aggressive Soft Tissue Sarcomas

We aimed to investigate the clinical significance of the expression of NY-ESO-1 and MAGE-A4 in soft tissue sarcoma (STS). Immunostaining for NY-ESO-1, MAGE-A4, and Ki67 was performed using pathological specimens harvested from 10 undifferentiated pleomorphic sarcoma (UPS), nine myxofibrosarcoma (MFS), and three malignant peripheral nerve sheath tumor (MPNST) patients treated at our hospital. We examined the correlation of NY-ESO-1 and MAGE-A4 expression levels with tumor size, histological grade, and SUVmax values. Positive cell rates of various markers were also compared between patients in remission and those who were not in remission. The rates of cases positive for NY-ESO, MAGE-A4, and Ki67 were 50%, 63.6%, and 90.9%, respectively. The average rates of cells positive for NY-ESO, MAGE-A4, and Ki67 in all STS types were 18.2%, 39.4%, and 16.8%, respectively. A positive correlation was observed between rates of cells positive for NY-ESO-1 and MAGE-A4 and between NY-ESO-1 and MAGE-A4 expression levels and clinical features. There was no significant difference in the positive cell rate of NY-ESO-1 or MAGE-A4 between remission and non-remission cases. Our results suggest that NY-ESO-1 and MAGE-A4 expression may be useful for the diagnosis and prognostication of UPS, MFS, and MPNST.

Overall Survival of Patients with Myxofibrosarcomas: An Epidemiological Study

Myxofibrosarcoma (MFS) is a rare mesenchymal soft tissue sarcoma type, with a high local recurrence (LR) rate. Robust epidemiological data on MFS are lacking. We, therefore, aimed to identify prognostic factors and describe real-life outcomes of a large cohort of 908 MFS patients obtained from the nationwide database of the Netherlands Cancer Registry and diagnosed between 2002 and 2019. Median Overall survival (OS) was 155 (range 0.1-215) months, with a five-year OS of 67.7%. No improvement of OS was found over time. Multivariable Cox regression survival analysis demonstrated known prognostic factors for OS, such as older age, tumour size, and histological grade with the addition of sex. Surgery at sarcoma expertise centres, instead of general hospitals, was associated with better OS outcomes. In a subcohort of 177 patients, 39% developed LR with a median time to recurrence of 20 months. From LR on, the median OS was 64.0 months (CI 95% 38.5-89.5). In 28%, distant metastases were diagnosed with a median OS of 34.3 months (CI 95% 28.8-39.8) after diagnosis of the primary tumour. In this largest nationwide cohort so far, survival outcomes and recurrence rates for MFS patients did not improve over time, emphasizing the need to improve treatment strategies and suggesting a role for sarcoma expertise centres.

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.

A Functional Precision Oncology Approach to Identify Treatment Strategies for Myxofibrosarcoma Patients

In this era of precision medicine, numerous workflows for the targeting of high-recurrent mutations in common tumor types have been developed, leaving patients with rare diseases with few options. Here, we implement a functional precision oncology approach utilizing comprehensive genomic profiling in combination with high-throughput drug screening, to identify tumor-specific drug sensitivities for patients with rare tumor types such as myxofibrosarcoma. From a patient with a high-grade myxofibrosarcoma, who was enrolled in the Englander Institute for Precision Medicine (EIPM) program, we established patient-derived 3D sarco-spheres and xenograft models for functional testing. In the absence of a large cohort of clinically similar cases, high-throughput drug screening was performed on the patient-derived cells, and compared with two other myxofibrosarcoma lines and a benign fibroblast line to functionally identify tumor-specific drug sensitivities. The addition of functional drug sensitivity testing to complement genomic profiling identified multiple therapeutic options that were further validated in patient derived xenograft models. Genomic analyses detected the frequently known codeletion of the tumor suppressors CDKN2A/B together with the methylthioadenosine phosphorylase (MTAP) and a TP53 E286fs*50 mutation. High-throughput drug screening demonstrated tumor-specific sensitivity to compounds targeting the cell cycle. Based on genomic analysis and high-throughput drug screening, we show that targeting the cell cycle in these tumors is a powerful approach. IMPLICATIONS: This study demonstrates the potential of functional testing to aid clinical decision making for patients with rare or molecularly complex malignancies when combined with comprehensive genomic profiling.

Establishment and Characterization of NCC-MFS5-C1: A Novel Patient-Derived Cell Line of Myxofibrosarcoma

Myxofibrosarcoma (MFS) is a highly aggressive malignancy with complex karyotypes and a postoperative recurrence tendency, owing to its strong invasiveness. Although systemic chemotherapy is considered in patients with unresectable MFS, the efficacy of conventional chemotherapy is hitherto unclear. Recently, drug screening analysis using a large number of tumor cell lines has been attempted to discover novel therapeutic candidate drugs for common cancers. However, the number of MFS cell lines is extremely small because of its low incidence-this hinders the conduction of screening studies and slows down the development of therapeutic drugs. To overcome this problem, we established a novel MFS cell line, NCC-MFS5-C1, which was shown to harbor typical MFS genetic abnormalities and thus had useful properties for in vitro studies. We conducted the largest integrated screening analysis of 210 drugs using NCC-MFS5-C1 cells along with four MFS cell lines, which we previously reported. Bortezomib (a proteasome inhibitor) and romidepsin (a histone deacetylase inhibitor) showed stronger antitumor effects than the standard drug, doxorubicin. Therefore, the NCC-MFS5-C1 cell line can potentially contribute to elucidating MFS pathogenesis and developing a novel MFS treatment.

Vascular Proximity Increases the Risk of Local Recurrence in Soft-Tissue Sarcomas of the Thigh-A Retrospective MRI Study

Simple Summary

Proximity to major vessels increases risk of local recurrence in soft tissue sarcomas of the thigh. When major vessels were observed to be surrounded by the tumor on preoperative MRI, vascular resection and by-pass reconstruction offered a better local control.

Abstract

The aim of this study was to establish the prognostic effects of the proximity of the tumor to the main vessels in patients affected by soft tissue sarcomas (STS) of the thigh. A total of 529 adult patients with deeply seated STS of the thigh and popliteal fossa were included. Vascular proximity was defined on MRI: type 1 > 5 mm; type 2 ≤ 5 mm and >0 mm; type 3 close to the tumor; type 4 enclosed by the tumor. Proximity to major vessels type 1–2 had a local recurrence (LR) rate lower than type 3–4 (p < 0.001). In type 4, vascular by-pass reduced LR risk. On multivariate analysis infiltrative histotypes, high FNLCC grade, radiotherapy administration, and type 3–4 of proximity to major vessels were found to be independent prognostic factors for LR. We observed an augmented risk of recurrence, but not of survival as the tumor was near to the major vessels. When major vessels were found to be surrounded by the tumor on preoperative MRI, vascular resection and bypass reconstruction offered a better local control.

Risk factors for the development of local recurrence in extremity soft-tissue sarcoma

INTRODUCTION

Local recurrence (LR) is one of the main pitfalls in surgery for extremities soft tissue sarcoma (eSTS). Achieving clear histopathological margins is the most important factor to reduce the risk of LR, but the ability to do so depends on not only surgical technique but also the interplay between tumor biology, anatomical location and surgical approach. The balance between postoperative morbidity and oncological benefits in reducing the risk of LR needs to be considered.

AREAS COVERED

This review will cover which etiological factors for the development of eSTS lead to an increased risk of LR and discuss histological subtypes that have a high risk of LR and which surgical and neoadjuvant therapeutic strategies can minimize the risk of LR.

EXPERT OPINION

The traditional view that surgical radicality always results in low rates of LR, while marginality alone always leads to high rates of relapse, is outdated. In the modern era of surgical oncology, limb salvage and high-level function after resectional surgery are the key surgical goals. The best results are achieved by combining effective neoadjuvant treatments with planned bespoke oncological operations that consider the biological and anatomical factors of each individual sarcoma.

Oncological Outcomes in Patients with Appendicular Myxofibrosarcomas: A Retrospective Study

BACKGROUND

Myxofibrosarcoma (MFS) is notorious for its infiltrative growth pattern, making wide excisions difficult to achieve. Our objective was to assess the impact of surgical margins and other factors that affected rates of local recurrence (LR), distant metastasis (DM), and overall survival (OS) of individuals undergoing resection for MFS.

METHODS

We retrospectively reviewed the medical records of 209 patients with appendicular soft tissue sarcomas between January 2012 and June 2018. Of these, 29 patients (14%) were diagnosed with myxofibrosarcoma. These patients underwent a total of 33 resections. The pathological analyses were conducted by an experienced musculoskeletal (MSK) pathologist. Demographics data, operative details, adjuvant therapy, and oncological outcomes were assessed.

RESULTS

Of the 29 patients (33 resections), the overall LR rate was 24% (7/29) and the 2-year LR rate was 17% (5/29). Factors associated with negative oncological outcomes were as follows: tumor size ≤10 cm (2-year local recurrence-free rates (LRFRs), 65%; 95% CI, 44-86%; p=0.02) and positive surgical margins grouped with surgical margins ≤0.1 cm (hazard ratio (HR), 11.74; 95% CI, 1.41-97.74; p=0.02). Chemotherapy and radiotherapy together increased the 2-year LRFR (LRFR, 100%; 95% CI, 100%, p=0.001). Two-year DM and OS rates were 15% and 79%, respectively. Female gender was a predictor of distant metastasis. Local recurrence had a negative impact on overall survival. Intraoperative analysis of resection margin accuracy was 75% (12/16) when non-MSK pathologists were involved but 100% accurate (12/12) when analyzed by an MSK pathologist.

CONCLUSION

Myxofibrosarcomas showed high LR rates after treatment. Close margins (≤0.1 cm) should be considered as a risk factor for LR, and LR is associated with negative overall survival. Neoadjuvant therapy in terms of combined chemotherapy and radiation therapy associates with decreased LR rates. If intraoperative assessment of margins is to be done, it should be performed by an experienced MSK pathologist.

Idiopathic and radiation-induced myxofibrosarcoma in the head and neck-case report and literature review

BACKGROUND

Myxofibrosarcoma (MFS), especially radiation-Induced MFS (RIMFS) in the head and neck, is an extremely rare malignant fibroblastic tumor. The diagnosis and treatment of MFS remain great challenges. In the present study, we presented one case of RIMFS. Combined with previous literature, the clinical features, essentials of diagnosis, and treatment modalities of MFS in the head and neck were reviewed to better understand this rare entity.

CASE PRESENTATION

We reported a case of RIMFS under the left occipital scalp in a 20-year-old girl with a history of medulloblastoma surgery and radiotherapy in 2006. A total tumor resection was performed with preservation of the overlying scalp the underlying bone, and no adjuvant therapy was administered after the first operation. The postoperative pathological diagnosis was high-grade MFS. The tumor relapsed 6 months later, and then, a planned extensive resection with negative surgical margins was carried out, followed by radiotherapy. No relapse occurred in a 12-month postoperative follow-up.

CONCLUSIONS

Planned gross total resection (GTR) with negative margins is the reasonable choice and footstone of other treatments for MFS. Ill-defined infiltrated borders and the complicated structures make it a great trouble to achieve total resection of MFS in the head and neck, so adjuvant radiotherapy and chemotherapy seem more necessary for these lesions.