EWSR1::WT1 Fusions in Neoplasms Other Than Conventional Desmoplastic Small Round Cell Tumor: Three Tumors Occurring Outside the Female Genital Tract.

Desmoplastic small round cell tumor (DSRCT) is a high-grade, primitive round cell sarcoma classically associated with prominent desmoplastic stroma, coexpression of keratin and desmin, and a characteristic EWSR1::WT1 gene fusion. DSRCT typically arises in the abdominopelvic cavity of young males with diffuse peritoneal spread and poor overall survival. Although originally considered to be pathognomonic for DSRCT, EWSR1::WT1 gene fusions have recently been detected in rare tumors lacking the characteristic morphologic and immunohistochemical features of DSRCT. Here, we report 3 additional cases of neoplasms other than conventional DSCRCT with EWSR1::WT1 gene fusions that occurred outside the female genital tract. Two occurred in the abdominopelvic cavities of a 27-year-old man and a 12-year-old girl, whereas the third arose in the axillary soft tissue of an 85-year-old man. All cases lacked prominent desmoplastic stroma and were instead solid and cystic with peripheral fibrous pseudocapsules and occasional intervening fibrous septa. Necrosis was either absent (1/3) or rare (2/3), and mitotic activity was low (<1 to 3 per 10 hpf). In immunohistochemical studies, there was expression of smooth muscle actin (3/3) and desmin (3/3), rare to focal reactivity for EMA (2/3), and variable expression of CK AE1/AE3 (1/3). Myogenin and MyoD1 were negative, and C-terminus-specific WT1 was positive in both cases tested (2/2). All 3 tumors followed a more indolent clinical course with 2 cases demonstrating no evidence of disease at 20 and 44 months after resection. The patient from case 3 died of other causes at 14 months with no evidence of recurrence. DNA methylation profiling showed that the 3 cases clustered with DSRCT; however, they demonstrated fewer copy number variations with 2 cases having a flat profile (0% copy number variation). Differential methylation analysis with hierarchical clustering further showed variation between the 3 cases and conventional DSRCT. Although further study is needed, our results, in addition to previous reports, suggest that EWSR1::WT1 gene fusions occur in rare and seemingly distinctive tumors other than conventional DSRCT with indolent behavior. Proper classification of these unusual soft tissue tumors with EWSR1::WT1 gene fusions requires direct correlation with tumor morphology and clinical behavior, which is essential to avoid overtreatment with aggressive chemotherapy.

Advances in the classification of round cell sarcomas.

Round cell sarcomas represent a diagnostic challenge for pathologists, owing to the poorly differentiated features of these high-grade tumours. The diagnosis of round cell sarcoma requires large immunohistochemical panels and molecular testing in many cases. This spectrum of malignancies is largely dominated by Ewing sarcomas (ESs), which represent the most common family of these tumours. Nonetheless, new families have been delineated in the past few years, with the addition of two additional families in the 2020 World Health Organization classification of bone and soft tissue tumours, namely sarcomas with CIC rearrangements and sarcomas with BCOR alterations. EWSR1, one of the genes involved in the driver fusion of ESs, is also implicated in the translocation of many other tumours with heterogeneous lineages and variable levels of aggressiveness. Round cell sarcomas associated with fusions inwhichEWSR1is partnered with genes encoding transcription factors distinct from those of the 'Ewing family' represent a heterogeneous group of rare tumours that require further study to determine whether their fusions may or not define a specific subgroup. They include mainly sarcomas with NFATc2 rearrangements and sarcomas with PATZ1 rearrangements. At this point, PATZ1 fusions seem to be associated with tumours of high clinical and morphological heterogeneity. Molecular studies have also helped in the identification of more consistent biomarkers that give tremendous help to pathologists in triaging, if not diagnosing, these tumours in practice. This review compiles the latest accumulated evidence regarding round cell sarcomas, and discusses the areas that are still under investigation.

Natural Changes in Radiological and Radiomics Features on MRIs of Soft-Tissue Sarcomas Naïve of Treatment: Correlations With Histology and Patients' Outcomes.

BACKGROUND: Because of long diagnostic intervals, soft-tissue sarcoma (STS) patients can undergo several MRIs before treatments. However, only the latest pre-treatment MRI is used in clinical practice and the natural changes in MRI presentations of STS occurring before any medical procedure remain unknown. PURPOSE: To qualitatively and quantitatively depict the natural history of MRI presentations of STS prior to medical intervention, to investigate their prognostic value, and to compare methods to calculate the changes in radiomics features (named delta-radiomics features). STUDY TYPE: Retrospective. SUBJECTS: Sixty-eight patients with locally advanced histologically proven STS and two pre-treatment contrast-enhanced (CE) MRIs (median age: 64 years, median delay between MRIs: 77 days). FIELD STRENGTH/SEQUENCE: Two-dimensional (2D) turbo spin echo (TSE) T1-weighted-imaging (WI) and T2-WI; 2D TSE or 3D gradient echo CE-T1-WI at 1.5 T. Radiomics analysis was performed on 2D TSE CE-T1-WI. ASSESSMENT: Three radiologists independently reported morphological features, evaluating changes in STS dimensions, intra-tumoral necrotic and hemorrhagic signals and heterogeneity, and changes in the tumor peritumoral enhancement, edema, and tail sign. After homogenizing the MRIs to account for differences in acquisition parameters, STS were 3D-segmented on both CE-T1-WI MRIs and radiomic features (RFs) were extracted. Changes in RFs between the two MRIs were calculated according to five methods: absolute, absolute/time between MRIs, relative, relative/time between MRIs, and log ratio. Histopathological samples were reviewed to count mitosis and Ki67 immunostaining. Survival data regarding local relapse, metastatic relapse, and disease-related deaths were collected. STATISTICAL TESTS: Reproducibility analysis (using intra-class correlation coefficient and [weighted] kappa), hierarchical clusterings based on changes in RFs, survival analyses (using Cox regressions), and association with histopathology (using Student's t-test, Wilcoxon, or Chi-squared test). A P-value of <0.05 was considered to be statistically significant. RESULTS: There were 15 and 26 local and metastatic progressions, respectively. Average tumor size increase between scans was +39.8%. Metastatic relapse-free survival (MFS) was associated with: increases in size, tumor heterogeneity on T1-WI, T2-WI, and CE-T1-WI, necrotic signal, peritumoral enhancement, and tail sign. Local relapse-free survival (LFS) was associated with: increase in tumor heterogeneity on T1-WI, necrotic signal, hemorrhagic signal and peritumoral edema, and clusters based on the logarithmic changes in RFs (Log-RF). Increase in heterogeneity on CE-T1-WI and Log-RF clusters were independent predictors for MFS and LFS, respectively, in stepwise multivariate Cox regression (hazard ratio [HR] = 2.78 and HR = +∞ respectively). Associations were found between changes in necrotic signal, heterogeneity on CE-T1-WI and peritumoral enhancement, and histological markers of proliferation. DATA CONCLUSION: Changes in MRI presentation of STS before any treatment are frequent, associated with histopathology, and could help in patients' prognostication, in addition to baseline MRI feature. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY: Stage 3.

Reconstruction of elbow flexion after sarcoma excision by a unipolar pedicled latissimus dorsi flap.

INTRODUCTION: The latissimus dorsi flap is widely used in plastic surgery for covering the upper limb but also for reconstruction the function of the elbow or shoulder. We describe a case of a sarcoma of the anterior compartment of the arm, the surgical removal then the covering and reconstruction of the elbow flexion. This case was carried out by a unipolar pedicled flap of the latissimus dorsi. MATERIAL AND METHODS: Three steps were performed (excision, flap preparation and flap fixation). The functional results (muscle strength, MRC scale) and range of motion (ROM) were analyzed. We performed a small literature review to compare the results. RESULTS: A complete excision (R0) was carried out with a good vitality of the latissimus dorsi flap. A rapid scarring was obtained, allowing an early start of adjuvant radiotherapy. Muscular strength was 33% less compared to preoperative, MRC scale was classified 4. ROM of the elbow were rated at -10/0/130. One year after the operation, the patient is still in remission. CONCLUSION: Our functional results are comparable to those found in the literature. The muscle strength in our case appears to be superior, probably linked to a brachio-radialis muscle still functional. No difference in function has been found in the literature between a unipolar or a bipolar transfer of the latissimus dorsi. This case report confirms the reliable and effective nature of the latissimus dorsi flap. The use of this flap for reconstruction after sarcoma surgery has only few reports in the literature.

Surgical Margins and Adjuvant Therapies in Malignant Phyllodes Tumors of the Breast: A Multicenter Retrospective Study.

BACKGROUND: The optimal threshold of surgical margins for breast malignant phyllodes tumors (MPTs) and the impact of adjuvant chemotherapy and radiotherapy were investigated. PATIENTS AND METHODS: We conducted a multicenter nationwide retrospective study of all MPT cases with central pathological review within the French Sarcoma Group. Endpoints were local recurrence-free survival (LRFS), metastasis-free survival (MFS), and overall survival (OS) rates. RESULTS: Overall, 212 patients were included in the study. All non-metastatic patients underwent primary surgical treatment, including 58.6% of conservative surgeries. An R0 resection was achieved in 117 patients (59.4%: 26.9% of patients with 1-2 mm margins, 12.2% of patients with 3-7 mm margins, 20.3% of patients with ≥ 8 mm margins). Ninety-four patients (45%) underwent a second surgery (SS) to obtain R0 margins, with a final mastectomy rate of 72.6%. Radiotherapy and chemotherapy were performed in 91 (43.1%) and 23 patients (10.9%), respectively, but were not associated with better outcomes. Mastectomy was significantly associated with better LRFS (p < 0.001). Margins of 0, 1, or 2 mm with SS were associated with better MFS (hazard ratio [HR] 0.3, p = 0.005) and OS (HR 0.32, p = 0.005) compared with margins of 0-1-2 mm without SS. Wider margins (> 8 mm) were not superior to margins of 3-7 mm (3-7 mm vs. > 8 mm; HR 0.81, p = 0.69). Age (HR 2.14, p = 0.038) and tumor necrosis (HR 1.96, p = 0.047) were found to be poor prognostic factors and were associated with MFS. CONCLUSIONS: This study suggests that 3 mm margins are necessary and sufficient for surgical management of MPTs, and emphasizes the importance of SS to obtain clear margins in case of 0-1-2 mm margins. No impact of adjuvant chemotherapy or radiotherapy was detected in this study.

Outcome of Patients with Soft-Tissue Sarcomas: An Age-Specific Conditional Survival Analysis.

BACKGROUND: Soft-tissue sarcomas (STSs) are a group of rare cancers that can occur at any age. Prognostic outcomes of patients with STS are usually established at the time of the patient's initial disease presentation. Conditional survival affords a dynamic prediction of prognosis for patients surviving a given period after diagnosis. Estimates of conditional survival can provide crucial prognostic information for patients and caregivers, guide subsequent cancer follow-up schedules, and impact decisions regarding management. This study aims to estimate conditional survival and prognostic factors in patients with STS according to age at diagnosis (≤75 years and ≥75 years). SUBJECTS, MATERIALS, AND METHODS: A total of 6,043 patients with nonmetastatic STS at first diagnosis who underwent complete surgical resection (R0 or R1) were assessed. Cox proportional hazards regression was used to establish prognostic factors of conditional metastasis-free survival and overall survival at 1, 2, and 5 years after diagnosis. RESULTS: Elderly patients have more adverse prognostic features at presentation and tend to receive less aggressive treatment than do younger patients. However, at baseline as well as at each conditional survival time point, the 5-year estimated probability of metastatic relapse decreases in both young and elderly patients and is almost identical in both groups at 2 years and 5 years after initial diagnosis. Prognostic factors for metastatic relapse and death change as patient survival time increases in both young and elderly patients. Grade, the strongest prognostic factor for metastatic relapse and death at baseline, is no longer predictive of metastatic relapse in patients surviving 5 years after initial diagnosis. Leiomyosarcoma is the histological subtype associated with the highest risk of metastatic relapse and death in young patients surviving 5 years after initial diagnosis. The positive impact on the outcome of peri-operative treatments tends to decrease and disappears in patients surviving 5 years after initial diagnosis. CONCLUSION: Conditional survival estimates show clinically relevant variations according to time since first diagnosis in both young and elderly patients with STS. These results can help STS survivors adjust their view of the future and STS care providers plan patient follow-up. IMPLICATIONS FOR PRACTICE: For patients with sarcoma who are followed up years after being treated for their disease, a common scenario is for the patient and caregivers to ask practitioners what the longer-term prognosis may be. The question posed to practitioners may be, "Doc, am I now cured? It's been 5 years since we finished treatment." Survival probability changes for patients who survive a given period of time after diagnosis, and their prognosis is more accurately described using conditional survival. By analyzing more than 6,000 sarcoma patients, an overall improvement was found in the risk of relapse as patients conditionally survive. Prognostic factors for metastatic relapse and death change as patient survival time increases in both young and elderly patients.

Collagen regeneration template in the management of full-thickness wounds: a prospective multicentre study.

OBJECTIVE: To evaluate the tolerance and healing rate of a collagen regeneration template in covering full-thickness wounds, including rate of adverse events. METHOD: In this prospective, multicentre study, patients with a full-thickness wound underwent two-stage surgery consisting of implantation of a collagen regeneration template followed by a split-thickness skin graft (STSG). Patients were followed-up for 12 months. Adverse events arising from either the implantation or STSG were evaluated. RESULTS: Of the 33 patients included in the study, 29 completed the full follow-up period. During the study, 13 adverse events occurred at the treated wound site, as reported by 11 patients during follow-up. These included local infection (n=5), a diffuse infection (n=1) and non-infectious seroma under the silicon layer (n=1). The mean percentage of take of the collagen template at 21±7 days after implantation was 81.2% of the treated surface. The mean percentage of take of STSG at 28 days after grafting was 84.4% of grafted surface. STSG was successful in 28 patients, but was completely rejected at 12 months for one patient. Mean functional score at 12 months, as evaluated by the treating surgeons, was 76.8/100 and mean aesthetic score was 62.7/100. CONCLUSION: This study found use of a collagen regeneration template to be a safe procedure for the coverage of full thickness-wounds.

Secondary Reconstruction of Calvarial Defects by Using Free Flap: Report of Consecutive Cases and Analysis of Strategy.

INTRODUCTION: Multiplication of incisions and/or radiotherapy on the scalp, lead to skin necrosis and chronic osteitis. In this situation, reconstructive surgery can be useful to cover complex lack of tissue. MATERIALS AND METHODS: The 5 patients were treated with the neurosurgery department of our hospital. The procedure included debridement of the infected calvarian bone and tissues and coverage by free antebrachial flap. A 2 stages skin graft, using a dermal regeneration template, or direct closure was used for the donor site. Evaluation of flap quality and donor site morbidity was done during hospitalization and 3 months after the procedure. RESULTS: The procedure was achieved on 5 patients. All the patients were healed 3 months after surgery. For 1 patient, a second procedure was done in emergency for anastomosis revision. There was non-complication concerning the donor site. All the patients healed with a good coverage. CONCLUSION: Treatment of calvarian bone necrosis needs a very good and reliable coverage, such as free flap can provide. In our opinion, the antebrachial free flap is an interesting option, despite the fact that it is still underused for scalp coverage.

Alternative PDGFD rearrangements in dermatofibrosarcomas protuberans without PDGFB fusions.

Dermatofibrosarcoma protuberans is underlined by recurrent collagen type I alpha 1 chain-platelet-derived growth factor B chain (COL1A1-PDGFB) fusions but ~ 4% of typical dermatofibrosarcoma protuberans remain negative for this translocation in routine molecular screening. We investigated a series of 21 cases not associated with the pathognomonic COL1A1-PDGFB fusion on routine fluorescence in situ hybridization (FISH) testing. All cases displayed morphological and clinical features consistent with the diagnosis of dermatofibrosarcoma protuberans. RNA-sequencing analysis was successful in 20 cases. The classical COL1A1-PDGFB fusion was present in 40% of cases (n = 8/20), and subsequently confirmed with a COL1A1 break-apart FISH probe in all but one case (n = 7/8). 55% of cases (n = 11/20) displayed novel PDGFD rearrangements; PDGFD being fused either to the 5' part of COL6A3 (2q37.3) (n = 9/11) or EMILIN2 (18p11) (n = 2/11). All rearrangements led to in-frame fusion transcripts and were confirmed at genomic level by FISH and/or array-comparative genomic hybridization. PDGFD-rearranged dermatofibrosarcoma protuberans presented clinical outcomes similar to typical dermatofibrosarcoma protuberans. Notably, the two EMILIN2-PDGFD cases displayed fibrosarcomatous transformation and homozygous deletions of CDKN2A at genomic level. We report the first recurrent molecular variant of dermatofibrosarcoma protuberans involving PDGFD, which functionally mimic bona fide COL1A1-PDGFB fusions, leading presumably to a similar autocrine loop-stimulating PDGFRB. This study also emphasizes that COL1A1-PDGFB fusions can be cytogenetically cryptic on FISH testing in a subset of cases, thereby representing a diagnostic pitfall that pathologists should be aware of.

Free serratus anterior artery perforator flap: a case report with an anatomic and radiological study.

Perforator flaps have become very popular in reconstructive surgery. The thoracodorsal and lateral thoracic artery perforator flaps are highly studied, and successful clinical series have been reported, whereas the literature concerning the lateral intercostal and serratus anterior artery perforator flaps is quite poor and their vascular anatomy needs yet to be clarified. We describe a case of free serratus anterior artery perforator flap for the reconstruction of a dorsal defect of the foot, followed by an anatomic and radiological study. A 17-year-old boy reported a fracture of the first and second metatarsal bone of the left foot, with a dorsal skin defect, due to a motorcycle accident. After the osteosynthesis treatment, a perforator was identified through a handheld Doppler in the lateral chest area and a cutaneous paddle was designed. Retrograde dissection revealed the perforator's direct link to the serratus anterior pedicle. In our knowledge, an elucidated method to preoperatively visualize the perforating vessel of the serratus anterior artery has not yet been described. Thus, an anatomic study on 8 hemithorax and a radiological study on 33 computed tomographic angiographies of the chest were carried out to clarify the vascular anatomy of the serratus anterior artery perforators and to verify the possibility of their preoperative visualization. The authors believe that the serratus anterior artery perforator could be preoperatively investigated, thus making this flap a valuable option when harvesting a perforator flap in the lateral chest area.

Chronic ischaemia does not appear to hinder healing with Integra(®) : implementation at a tibial artery bypass site.

Wounds with exposed vessels, especially in artery bypass procedures, can pose a barrier to adequate skin healing. Skin grafts or flaps are sometimes difficult to perform in the face of the ischaemia that is often present in such cases. We report a case of a 73-year-old man who presented with grade IV peripheral arterial disease necessitating salvage of the lower limb using artery bypass surgery. Immediate exposure of femorotibial artery secondary to skin necrosis following the bypass led us to propose an innovative means of wound coverage using Integra(®) , a well-known dermal regeneration template. The wound healed uneventfully with an appearance similar to that of the adjacent skin. Integra(®) seems to be less demanding in terms of the vascular wound bed and the degree of oxygenation than a conventional skin graft. This finding could support further indications for this dermal regeneration template.

Autologous fat grafting for cosmetic breast augmentation: a systematic review.

BACKGROUND: Breast augmentation is one of the most popular aesthetic surgical procedures. The only potential alternative is autologous fat grafting (AFG), which is not new in principle. This procedure has been used on native breasts since 2009, following the recommendations of some learned societies. OBJECTIVES: We performed a systematic review to determine the current worldwide status of fat grafting for aesthetic breast augmentation. METHODS: A systematic review of the literature following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis criteria was conducted using the PubMed, EmBASE, and Cochrane library databases. This protocol was registered at the National Institute for Health Research, Prospective Register of Systematic Reviews. RESULTS: A total of 42 articles published between 1987 and July 2014 were included. Most of the studies had a low level of evidence, with only one level 2 study, published by Spear (2014), a prospective cohort study which included 10 patients. The publications were from North America, Europe, and Asia. The indications were aesthetic augmentation (92.4%) and congenital malformation (7.6%). Two cases of cancer were reported among the 2023 patients included (0.09%), with a mean follow-up of 22 months, although the follow-up was insufficient for medium- and long-term cancer diagnoses. CONCLUSIONS: AFG seems to be a major tool in this field, but we must remain cautious about its systematization for this indication. Preoperative patient selection is essential but underreported. AFG appears particularly relevant in breast malformations. We believe that this method should be practiced within the scope of a national or international registry with proper follow-up of patients.

Integration of pre-treatment computational radiomics, deep radiomics, and transcriptomics enhances soft-tissue sarcoma patient prognosis.

Our objective was to capture subgroups of soft-tissue sarcoma (STS) using handcraft and deep radiomics approaches to understand their relationship with histopathology, gene-expression profiles, and metastatic relapse-free survival (MFS). We included all consecutive adults with newly diagnosed locally advanced STS (N = 225, 120 men, median age: 62 years) managed at our sarcoma reference center between 2008 and 2020, with contrast-enhanced baseline MRI. After MRI postprocessing, segmentation, and reproducibility assessment, 175 handcrafted radiomics features (h-RFs) were calculated. Convolutional autoencoder neural network (CAE) and half-supervised CAE (HSCAE) were trained in repeated cross-validation on representative contrast-enhanced slices to extract 1024 deep radiomics features (d-RFs). Gene-expression levels were calculated following RNA sequencing (RNAseq) of 110 untreated samples from the same cohort. Unsupervised classifications based on h-RFs, CAE, HSCAE, and RNAseq were built. The h-RFs, CAE, and HSCAE grouping were not associated with the transcriptomics groups but with prognostic radiological features known to correlate with lower survivals and higher grade and SARCULATOR groups (a validated prognostic clinical-histological nomogram). HSCAE and h-RF groups were also associated with MFS in multivariable Cox regressions. Combining HSCAE and transcriptomics groups significantly improved the prognostic performances compared to each group alone, according to the concordance index. The combined radiomic-transcriptomic group with worse MFS was characterized by the up-regulation of 707 genes and 292 genesets related to inflammation, hypoxia, apoptosis, and cell differentiation. Overall, subgroups of STS identified on pre-treatment MRI using handcrafted and deep radiomics were associated with meaningful clinical, histological, and radiological characteristics, and could strengthen the prognostic value of transcriptomics signatures.

Comprehensive Molecular Characterization of a Large Series of Calcified Chondroid Mesenchymal Neoplasms Widening Their Morphologic Spectrum.

Recently, FN1 fusions to receptor tyrosine kinase genes have been identified in soft tissue tumors with calcified chondroid matrix named calcifying chondroid mesenchymal neoplasms (CCMNs). We collected 33 cases of CCMN from the French network for soft tissue and bone tumors. We performed whole-exome RNA sequencing, expression analysis, and genome-wide DNA methylation profiling in 33, 30, and 20 cases of CCMN compared with a control group of tumors, including noncalcified tenosynovial giant cell tumor (TGCT). Among them, 15 cases showed morphologic overlap with soft tissue chondroma, 8 cases with tophaceous pseudogout, and 10 cases with chondroid TGCT. RNA-sequencing revealed a fusion of FN1 in 76% of cases (25/33) with different 5' partners, including most frequently FGFR2 (14 cases), TEK or FGFR1. Among CCMN associated with FGFR1 fusions, 2 cases had overexpression of FGF23 without tumor-induced osteomalacia. Four CCMN had PDGFRA::USP8 fusions; 3 of which had histologic features of TGCT and were located in the hip, foot, and temporomandibular joint (TMJ). All cases with FN1::TEK fusion were located at TMJ and had histologic features of TGCT with or without chondroid matrix. They formed a distinct cluster on unsupervised clustering analyses based on whole transcriptome and genome-wide methylome data. Our study confirms the high prevalence of FN1 fusions in CCMN. In addition, through transcriptome and methylome analyses, we have identified a novel subgroup of tumors located at the TMJ, exhibiting TGCT-like features and FN1::TEK fusions.

Improved Metastatic-Free Survival after Systematic Re-Excision Following Complete Macroscopic Unplanned Excision of Limb or Trunk Soft Tissue Sarcoma.

BACKGROUND: Whether re-excision (RE) of a soft tissue sarcoma (STS) of limb or trunk should be systematized as adjuvant care and if it would improve metastatic free survival (MFS) are still debated. The impact of resection margins after unplanned macroscopically complete excision (UE) performed out of a NETSARC reference center or after second resection was further investigated. METHODS: This large nationwide series used data from patients having experienced UE outside of a reference center from 2010 to 2019, collected in a French nationwide exhaustive prospective cohort NETSARC. Patient characteristics and survival distributions in patients reexcised (RE) or not (No-RE) are reported. Multivariate Cox proportional hazard model was conducted to adjust for classical prognosis factors. Subgroup analysis were performed to identify which patients may benefit from RE. RESULTS: Out of 2371 patients with UE for STS performed outside NETSARC reference centers, 1692 patients were not reviewed by multidisciplinary board before treatment decision and had a second operation documented. Among them, 913 patients experienced re-excision, and 779 were not re-excised. Characteristics were significantly different regarding patient age, tumor site, size, depth, grade and histotype in patients re-excised (RE) or not (No-RE). In univariate analysis, final R0 margins are associated with a better MFS, patients with R1 margins documented at first surgery had a better MFS as compared to patients with first R0 resection. The study identified RE as an independent favorable factor for MFS (HR 0.7, 95% CI 0.53-0.93; p = 0.013). All subgroups except older patients (>70 years) and patients with large tumors (>10 cm) had superior MFS with RE. CONCLUSIONS: RE might be considered in patients with STS of limb or trunk, with UE with macroscopic complete resection performed out of a reference center, and also in originally defined R0 margin resections, to improve LRFS and MFS. Systematic RE should not be advocated for patients older than 70 years, or with tumors greater than 10 cm.

Technical considerations for isolated limb perfusion: A consensus paper.

BACKGROUND: Isolated limb perfusion (ILP) is a well-established surgical procedure for the administration of high dose chemotherapy to a limb for the treatment of advanced extremity malignancy. Although the technique of ILP was first described over 60 years ago, ILP is utilised in relatively few specialist centres, co-located with tertiary or quaternary cancer centres. The combination of high dose cytotoxic chemotherapy and the cytokine tumour necrosis factor alpha (TNFα), mandates leakage monitoring to prevent potentially serious systemic toxicity. Since the procedure is performed at relatively few specialist centres, an ILP working group was formed with the aim of producing technical consensus guidelines for the procedure to streamline practice and to provide guidance for new centres commencing the technique. METHODS: Between October 2021 and October 2023 a series of face to face online and hybrid meetings were held in which a modified Delphi process was used to develop a unified consensus document. After each meeting the document was modified and recirculated and then rediscussed at subsequent meeting until a greater than 90% consensus was achieved in all recommendations. RESULTS: The completed consensus document comprised 23 topics in which greater than 90% consensus was achieved, with 83% of recommendations having 100% consensus across all members of the working group. The consensus recommendations covered all areas of the surgical procedure including pre-operative assessment, drug dosing and administration, perfusion parameters, hyperthermia, leakage monitoring and theatre logistics, practical surgical strategies and also post-operative care, response evaluation and staff training. CONCLUSION: We present the first joint expert-based consensus statement with respect to the technical aspects of ILP that can serve as a reference point for both existing and new centres in providing ILP.

Analysis of the Peritumoral Tissue Unveils Cellular Changes Associated with a High Risk of Recurrence.

BACKGROUND: The management of soft-tissue sarcoma (STS) relies on a multidisciplinary approach involving specialized oncological surgery combined with other adjuvant therapies to achieve optimal local disease control. Purpose and Results: Genomic and transcriptomic pseudocapsules of 20 prospective sarcomas were analyzed and revealed to be correlated with a higher risk of recurrence after surgery. CONCLUSIONS: A peritumoral environment that has been remodeled and infiltrated by M2 macrophages, and is less expressive of healthy tissue, would pose a significant risk of relapse and require more aggressive treatment strategies.

Giant Cell Tumors With HMGA2::NCOR2 Fusion : Clinicopathologic, Molecular, and Epigenetic Study of a Distinct Entity.

Giant cell tumors (GCTs) with high mobility group AT-Hook 2 ( HMGA2 )::nuclear receptor corepressor 2 ( NCOR2 ) fusion are rare mesenchymal tumors of controversial nosology, which have been anecdotally reported to respond to CSFR1 inhibitors. Here, we performed a comprehensive study of 6 GCTs with HMGA2::NCOR2 fusion and explored their relationship with other giant cell-rich neoplasms. Tumors occurred in 4 females and 2 males ranging in age from 17 to 32 years old (median 24). Three lesions originated in subcutaneous soft tissue and 3 in bone. Tumor size ranged from 20 to 33 mm (median 27 mm). The lesions had a nodular/multinodular architecture and were composed of sheets of mononuclear "histiocytoid" cells with uniform nuclei intermingled with multinucleated giant cells. Mitotic activity was low and nuclear atypia and metaplastic bone were absent. Variable findings included necrosis, cystic degeneration, lymphocytic infiltrate (sometimes forming nodules), and xanthogranulomatous inflammation. On immunohistochemistry, all cases focally expressed pan-keratin and were negative with SATB2 and H3.3G34W. Whole RNA-sequencing was performed in all cases of GCT with HMGA2::NCOR2 fusion and a subset of giant cell-rich tumors (tenosynovial-GCT, n = 19 and "wild-type" GCT of soft tissue, n = 9). Hierarchical clustering of RNA-sequencing data showed that GCT with HMGA2::NCOR2 fusion formed a single cluster, independent of the other 2 entities. Methylome profiling showed similar results, but the distinction from "wild-type" GCT of soft tissue was less flagrant. Gene expression analysis showed similar levels of expression of the CSF1/CSFR1 axis between GCT with HMGA2::NCOR2 fusion and tenosynovial-GCT, supporting their potential sensitivity to CSFR1 inhibitors. Clinical follow-up was available for 5 patients (range: 10 to 64 mo; median 32 mo). Three patients (60%) experienced local recurrences, whereas none had distant metastases or died of disease. Overall, our study confirms and expands previous knowledge on GCT with HMGA2::NCOR2 fusion and supports its inclusion as an independent entity.

Deep learning predicts patients outcome and mutations from digitized histology slides in gastrointestinal stromal tumor.

Risk assessment of gastrointestinal stromal tumor (GIST) according to the AFIP/Miettinen classification and mutational profiling are major tools for patient management. However, the AFIP/Miettinen classification depends heavily on mitotic counts, which is laborious and sometimes inconsistent between pathologists. It has also been shown to be imperfect in stratifying patients. Molecular testing is costly and time-consuming, therefore, not systematically performed in all countries. New methods to improve risk and molecular predictions are hence crucial to improve the tailoring of adjuvant therapy. We have built deep learning (DL) models on digitized HES-stained whole slide images (WSI) to predict patients' outcome and mutations. Models were trained with a cohort of 1233 GIST and validated on an independent cohort of 286 GIST. DL models yielded comparable results to the Miettinen classification for relapse-free-survival prediction in localized GIST without adjuvant Imatinib (C-index=0.83 in cross-validation and 0.72 for independent testing). DL splitted Miettinen intermediate risk GIST into high/low-risk groups (p value = 0.002 in the training set and p value = 0.29 in the testing set). DL models achieved an area under the receiver operating characteristic curve (AUC) of 0.81, 0.91, and 0.71 for predicting mutations in KIT, PDGFRA and wild type, respectively, in cross-validation and 0.76, 0.90, and 0.55 in independent testing. Notably, PDGFRA exon18 D842V mutation, which is resistant to Imatinib, was predicted with an AUC of 0.87 and 0.90 in cross-validation and independent testing, respectively. Additionally, novel histological criteria predictive of patients' outcome and mutations were identified by reviewing the tiles selected by the models. As a proof of concept, our study showed the possibility of implementing DL with digitized WSI and may represent a reproducible way to improve tailoring therapy and precision medicine for patients with GIST.

Natural speed of growth of untreated soft-tissue sarcomas: A dimension-based imaging analysis.

PURPOSE: The interval from first symptoms to diagnosis, staging and referral to reference center can last months for soft-tissue sarcoma (STS) patients. Meanwhile, patients can undergo different imaging that capture the 'natural' tumor changes, before medical intervention. Aim was to depict these 'natural' dimensional variations and to correlate them with patients' outcome. METHODS: Single-center retrospective study including all consecutive adults with newly-diagnosed STS, ≥2 pre-treatment imaging (CT-scan or MRI) on the tumor (Exam-0 and Exam-1), and managed in reference center between 2007 and 2018. Longest diameter (LD) and volume were calculated on both examinations to obtain the naïve dimensional growth before any intervention. SARCULATOR nomogram was applied on data at Exam-0 and Exam-1. Correlations with overall, metastatic and local relapse-free survivals (OS, MFS and LFS), and with pre-treatment pathological features were performed. RESULTS: 137 patients were included (median age: 65 years). Average naïve growth was +39.4% in LD and +503% in volume during an average Exam-0-to-Exam-1 interval of 130 days. The 10-year distant metastasis and OS predictions were different at Exam-0 and Exam-1 (P < 0.0001 for both). All the changes in radiological measurements significantly correlated with pre-treatment number of mitosis, grade and complex genomic (P-value range: <0.0001-0.0481). Multivariate Cox modeling identified the relative change in LD/month and absolute change in LD/month as independent predictors for OS and LFS, respectively (P = 0.0003 and 0.0001, respectively). CONCLUSION: When available, the natural speed of growth on pre-treatment imaging should be evaluated to improve the estimation of pre-treatment histological grade and patients' OS and LFS.