Clinical recommendations for treatment of localized angiosarcoma: A consensus paper by the Italian Sarcoma Group.

Angiosarcoma (AS) represents a rare and aggressive vascular sarcoma, posing distinct challenges in clinical management compared to other sarcomas. While the current European Society of Medical Oncology (ESMO) clinical practice guidelines for sarcoma treatment are applicable to AS, its unique aggressiveness and diverse tumor presentations necessitate dedicated and detailed clinical recommendations, which are currently lacking. Notably, considerations regarding surgical extent, radiation therapy (RT), and neoadjuvant/adjuvant chemotherapy vary significantly in localized disease, depending on each different site of onset. Indeed, AS are one of the sarcoma types most sensitive to cytotoxic chemotherapy. Despite this, uncertainties persist regarding optimal management across different clinical presentations, highlighting the need for further investigation through clinical trials. The Italian Sarcoma Group (ISG) organized a consensus meeting on April 1st, 2023, in Castel San Pietro, Italy, bringing together Italian sarcoma experts from several disciplines and patient representatives from "Sofia nel Cuore Onlus" and the ISG patient advocacy working group. The objective was to develop specific clinical recommendations for managing localized AS within the existing framework of sarcoma clinical practice guidelines, accounting for potential practice variations among ISG institutions. The aim was to try to standardize and harmonize clinical practices, or at least highlight the open questions in the local management of the disease, to define the best evidence-based practice for the optimal approach of localized AS and generate the recommendations presented herein.

Regorafenib in advanced solitary fibrous tumour: Results from an exploratory phase II clinical study.

BACKGROUND: To investigate the activity of regorafenib in advanced solitary fibrous tumour (SFT). METHODS: An Italian monocentric investigator-initiated exploratory single-arm Phase II trial was conducted of regorafenib in adult patients with advanced and progressive SFT, until progression or limiting toxicity. Prior treatment with antiangiogenics was allowed. Primary and secondary end-points were: overall response rate (ORR) by Choi criteria, and ORR by RECIST, progression-free survival (PFS), overall survival (OS). RESULTS: From January 2016 to February 2021, 18 patients were enroled [malignant-SFT = 13; dedifferentiated-SFT (D-SFT) = 4; typical-SFT (T-SFT) = 1]. Fourteen patients were pre-treated, in 12 cases with antiangiogenics (median [m-] lines of treatment = 3). Sixteen patients were evaluable for response (one screening failure; one early discontinuation). Six/16 (35.2%) required a definitive dose reduction. ORR by Choi was 37.5% (95% CI: 15.2-64.6), with 6/16 (37.5%) partial responses (PR), 6/16 (37.5%) stable disease (SD) and 4/16 (25%) progressions; 5/6 responses occurred in patients pre-treated with antiangiogenics. No responses were detected in D-SFT. Best RECIST responses were: 1/16 (6.2%) PR, 12/16 (75%) SD, 3/16 (18.8%) progressions. At 48.4 month m-FU, m-PFS by Choi was 4.7 (inter-quartile range: 2.4-13.1) months, with 31.2% patients progression-free at 1 year. CONCLUSION: Regorafenib showed activity in SFT, with 30% patients free-from-progression at one year. Responses were observed also in patients pretreated and refractory to another antiangiogenic agents. However, ORR and m-PFS were lower than reported with other antiangiogenics, and this was possibly due to discrepancies in the patient population and the high-rate of dose reductions.

Laparoscopic Cholecystectomy in Children: The Experience of Two Centers Focusing on Indications and Timing in the Era of "New Technologies".

BACKGROUND: In children, laparoscopic cholecystectomy (LC) is now considered the gold standard for gallbladder (GB) removal. In the past, hemolytic disorders associated with cholelithiasis represented the most frequent conditions requiring LC; this is being overtaken by cholelithiasis and biliary conditions in overweight or ex-premature children. AIMS: This study aims to describe current indications and timing for LC in pediatric patients. METHODS: Retrospective study. Data on previous medical therapy, ultrasound, pre- and intraoperative aspects, and histology were collected for patients treated in 2020-2023. RESULTS: In total, 45 patients were enrolled: 15 who underwent urgent surgery and 30 electives. Groups differed in terms of obesity rate, symptoms, ultrasound features, and intraoperative status. The most relevant risk factors for surgical complexity were age and pubertal stage, elevated cholestasis indexes, and gallbladder wall thickness > 3 mm at ultrasound. GB wall thickening ≥3 mm, US Murphy sign, fluid collections, and gallbladder distention on ultrasound correlated with high surgical scores. CONCLUSIONS: Indications for laparoscopic cholecystectomy in children seem to evolve caused by changing characteristics of the pediatric population. Patients with overweight/obesity may develop more complex GB diseases. Asymptomatic patients should be considered for surgery after observation, considering age and/or pubertal maturation when other risk factors are absent.

Pathological and radiological response following neoadjuvant treatments in primary localized resectable myxofibrosarcoma and undifferentiated pleomorphic sarcoma of the extremities and trunk wall.

BACKGROUND: To explore the correlation between pathological and radiological response to preoperative treatments and outcome in surgically treated patients with myxofibrosarcoma (MFS) and undifferentiated pleomorphic sarcoma (UPS). METHODS: All consecutive patients with primary localized MFS and UPS of the extremities and trunk wall surgically treated with curative intent at our center (2005-2021) were included. Clinical data including residual visible tumor (VT%) on surgical specimen and Response Evaluation Criteria in Solid Tumor (RECIST) were retrieved. Kaplan-Meier curves for overall survival and disease-free survival, and cumulative incidence of local relapse and distant metastasis were estimated in a competing risk framework according to RECIST and VT%, overall and by treatment group. Cox and Fine and Gray multivariable models were performed. RESULTS: Of 693 patients affected by primary MFS and UPS, 233 (66 MFS and 167 UPS) were treated by neoadjuvant chemotherapy (naChT), radiotherapy (naRT), or both (naChT-RT). VT% was ≤5% in 13/46 (28.2%), 24/99 (24.2%), and 40/88 (45.4%) patients, respectively. There were 11/46 (29.7%), 22/99 (22.7%), and 23/88 (26.1%) RECIST partial responses and 18/46 (48.6%), 59/99 (60.8%), and 60/88 (68.2%) RECIST stable disease, respectively. In naChT, a trend for a better survival was observed when VT% ≤5% (p = .09), whereas RECIST partial responses and stable disease had the same outcome. VT% was not associated with outcome in naRT or naChT-RT, whereas RECIST response was. CONCLUSION: In primary localized MFS and UPS treated with neoadjuvant therapies, VT% seems more relevant than size reduction after naChT, whereas the opposite is true when naRT is administered alone or concurrent to ChT.

Effectiveness of irinotecan plus trabectedin on a desmoplastic small round cell tumor patient-derived xenograft.

This study exploited a novel patient-derived xenograft (PDX) of desmoplastic small round cell tumor (DSRCT), which reproduces histomorphological and molecular characteristics of the clinical tumor, to assess the activity of cytotoxic and targeted anticancer agents. Antitumor effect was moderate for doxorubicin, pazopanib and larotrectenib [maximum tumor volume inhibition (max TVI), 55-66%], while trabectedin had higher activity (max TVI, 82%). Vinorelbine, irinotecan and eribulin achieved nearly complete tumor growth inhibition (max TVI, 96-98%), although tumors regrew after the end of treatment. The combination of irinotecan with either eribulin or trabectedin resulted in complete responses, which were maintained until the end of the experiment for irinotecan plus trabectedin. Irinotecan-based combinations nearly abrogated the expression of proteins of the G2/M checkpoint, preventing cell entrance in mitosis, and induced apoptotic and necroptotic cell death. Consistently, irinotecan plus trabectedin resulted in reprogramming of DSCRT transcriptome, with downregulation of E2F targets, G2/M checkpoint and mitotic spindle gene sets. This study emphasizes the importance of patient-derived preclinical models to explore new treatments for DSRCT and fosters clinical investigation into the activity of irinotecan plus trabectedin.

Organ Infiltration and Patient Risk After Multivisceral Surgery for Primary Retroperitoneal Liposarcomas.

BACKGROUND: The extent of histological organ involvement (HOI) to organs and structures of a retroperitoneal liposarcoma may have prognostic implications. This study investigated incidence, characteristics, and risk association of HOI in these patients. PATIENTS AND METHODS: Data of patients who underwent multivisceral resection for primary liposarcoma (2009-2014) were retrospectively analyzed. HOI was the variable of interest and was classified into four degrees: absent (HOI-0), perivisceral (HOI-1), initial (HOI-2), and advanced (HOI-3). Primary endpoint was overall survival (OS). Secondary endpoint was disease-free survival (DFS). The prognostic value of HOI was adjusted for preoperative treatment and the Sarculator nomogram score. RESULTS: A total of 109 patients were included. HOI-0, HOI-1, HOI-2, and HOI-3 were detected in 9 (8.3%), 11 (10.1%), 43 (39.4%), and 46 (42.2%) patients. Median follow-up was 8.4 years [interquartile range (IQR) 7.2-9.6 years]. There were 68 recurrences and 50 patient deaths observed, resulting in a 10-year OS and DFS of 51.1% [95% confidence interval (CI) 41.9-62.1%] and 34.1% (95% CI 25.2-46.1%), respectively. Clinically relevant HOIs (HOI-2 and HOI-3) were found in 35/45 (77.8%) and 54/64 (84.4%) cases of well- and de-differentiated liposarcomas, respectively. On multivariable survival analysis, patients with HOI-3 had significantly shorter OS (HOI-3 vs HOI-0/HOI-1 HR 2.92; p = 0.012) and DFS (HOI-3 vs HOI-0/HOI-1 HR 2.23; p = 0.045), independently of the nomogram score (OS: HR 2.93; p < 0.001; DFS: HR 1.78; p = 0.003). CONCLUSIONS: Initial and advanced HOIs are frequently detected in both well-differentiated and de-differentiated liposarcomas, supporting that multivisceral resection may be needed. HOI stratifies the risk of patients with primary retroperitoneal liposarcoma.

Preoperative Neutrophil-to-Lymphocyte Ratio and a New Inflammatory Biomarkers Prognostic Index for Primary Retroperitoneal Sarcomas: Retrospective Monocentric Study.

PURPOSE: Inflammatory biomarkers and neutrophil-to-lymphocyte ratio (NLR) are associated with prognosis in several tumors. Data on sarcomas are limited, and insufficient on retroperitoneal sarcoma (RPS). EXPERIMENTAL DESIGN: Patients with primary RPS operated between 2002 and 2016 were included. Hemoglobin, monocytes, NLR, platelet-to-lymphocyte ratio (PLR) were retrieved and analyzed both individually and combined into a prognostic index (IBPI). Correlation with clinicopathologic variables was studied, as well as postoperative morbidity according to NLR and IBPI risk categories. The association between overall survival (OS) and biomarkers and, in addition, the 7-year Sarculator-predicted OS probability (pOS) was analyzed using univariable and multivariable Cox models. RESULTS: 423/463 patients had complete data. The median follow-up was 84 months. The median NLR was 3.3 (IQR, 2.4-4.7), with significant variation across histologies. NLR was the only biomarker that independently predicted OS (HR, 1.2; 95% CI, 1.03-1.40; P = 0.02). The IBPI showed good discrimination for subgroups at different OS (log-rank test P < 0.0001). The Cox model for pOS alone showed a 7-year index of prediction accuracy of 26.9, which increased to 29.5 when IBPI was added to pOS as a complementary prognostic tool. IBPI was also associated with the risk of serious infectious postoperative complications (P = 0.0094; noninfectious complications, P = 0.6463). CONCLUSIONS: NLR was an independent prognostic factor for OS in RPS. When combined into a prognostic index with hemoglobin, monocytes, and PLR, it serves as a readily available prognostic tool addressing tumor-related inflammation and helps in classifying RPS risk in addition to the Sarculator nomogram.

Unexpected Detection of Skeletal Muscle Renal Cell Carcinoma Metastasis With 99m Tc-EDDA/HYNIC-Tyr3-Octreotide (Tektrotyd) Scan.

ABSTRACT: Somatostatin receptor scintigraphy with 99m Tc-Tektrotyd is widely used for the investigation of neuroendocrine tumors. Overexpression of somatostatin receptors has been shown in different tumor types including lymphomas, breast carcinoma, and renal cell carcinoma (RCC). Isolated case reports have shown that RCC metastases can be identified using somatostatin receptor imaging such as Octreoscan scintigraphy and 68 Ga-DOTATATE PET/CT. We report the case of a 70-year-old man with a history of surgically removed RCC who referred to 99m Tc-Tektrotyd scintigraphy for the evaluation of a pancreatic tail lesion. The scan revealed intense tracer uptake in a left splenius cervicis muscle lesion that on biopsy was consistent with metastatic RCC.

Renal cell carcinoma in children and adolescents: a retrospective study of a French-Italian series of 93 cases.

AIMS: Renal cell carcinomas (RCCs) represent 2-5% of kidney malignancies in children and adolescents. Appropriate diagnostic and classification are crucial for the correct management of the patients and in order to avoid inappropriate pre-operative chemotherapy, which is usually recommended if a Wilms' tumour is suspected. METHODS AND RESULTS: A French-Italian series of 93 renal cell carcinomas collected from 1990 to 2019 in patients aged less than 18 years was reclassified according to the 2016 World Health Organization (WHO) classification and the latest literature. TFE3 and TFEB fluorescence in-situ hybridisation (FISH) analyses and a panel of immunohistochemical stains were applied. The median age at diagnosis was 11 years (range = 9 months-17 years). MiT family (MiTF) translocation RCCs accounted for 52% of the tumours, followed by papillary (20%) and unclassified RCCs (13%). Other subtypes, such as SDHB-deficient and fumarate hydratase-deficient RCCs, represented 1-3% of the cases. We also described a case of ALK-rearranged RCC with a metanephric adenoma-like morphology. CONCLUSION: A precise histological diagnosis is mandatory, as targeted therapy could be applied for some RCC subtypes, i.e. MiTF-translocation and ALK-translocation RCC. Moreover, some RCC subtypes may be associated with a predisposition syndrome that will impact patients' and family's management and genetic counselling. A precise RCC subtype is also mandatory for the clinical management of the patients and inclusion in new prospective clinical trials.

Treatment strategies and outcomes of primary Myxofibrosarcomas in a large patients cohort.

BACKGROUND: this study analysed primary myxofibrosarcoma (MFS) to investigate patient outcomes focusing on histopathologic margins and perioperative treatments. PATIENTS AND METHODS: data from consecutive patients affected by primary and localized MFS of the extremities or trunk wall who underwent surgery (2002-2017) were analysed. Local recurrence (LR), amputation rate, incidence of distant metastasis (DM), and overall survival (OS) were studied. RESULTS: Of 293 included patients, 52 (17%) patients received perioperative treatments and 54 (18%) had positive microscopic histopathologic margins (R1). Median follow-up was 80 months (IQR, 49-109). 5-yr CCI of LR was 0.12 (SE: 0.02). Status of histopathologic margins (P < 0.001), tumour malignancy grade (P = 0.018) and size (P = 0023) were independent prognostic factor for LR. Nine amputations (amputation rate: 3%) were performed (N = 1 for primary tumour; N = 8 for LR). Larger tumour size (P = 0.015) and higher grade (P = 0.025) were independent prognostic factor for DM. 5-year OS was 0.84 (95%CI 0.79-0.88). Patient age (P = 0.008), tumour size (P = 0.013) and malignancy grade (P = 0.018) were independently associated to OS. In the subgroup of patients who had a re-excision for a primary MFS (N = 116, 40%), the presence of residual disease was not associated with LR, DM, or OS. CONCLUSION: in this study 5-year LR, DM and OS were 12%, 17%, and 84%, respectively. One in six patients had a positive surgical margin, which was a prognostic factor for LR, while DM and OS were predicted by tumour grade and size. Findings from this large patient cohort may set benchmarks for investigating new treatment options for MFS.

Refining the Approach to Patients with Primary Soft Tissue Sarcoma of the Extremities and Trunk Wall: Outcome Improvement Over Time at a Single Institution.

BACKGROUND: The improved outcome of extremity soft tissue sarcoma patients surgically treated until 2007 at the authors' institution was previously reported. This study updates the analysis at a later follow-up and extends the patients' cohort to assess changes in outcomes over time for extremity and superficial trunk soft tissue sarcoma (ESTSTS) treated at a single referral center. METHODS: All consecutive patients with primary localized adult-type ESTSTS surgically treated at the authors' institution between 1987 and 2017 were included and divided into group 1 (1987-2002) and group 2 (2003-2017) according to primary surgery year. Crude cumulative incidence (CCI) of sarcoma-specific mortality (SSM), local recurrence (LR), and distant metastases (DM) were calculated in a competing-risks framework. DM-free survival (DMFS) and post-DM survival were also assessed. RESULTS: The study identified 2382 patients. The median follow-up was 104 months (range, 63-127 months), and the post-DM follow-up was 76 months (range, 37-126 months). Since 2003, an increased adoption of preoperative treatments was observed: the use of chemotherapy, radiotherapy and combined chemoradiotherapy went from 10.5% to 23.7%, from 1.7% to 17.8%, and from 1% to 11.8% respectively. This change in treatment strategies was associated to an improvement in CCI-SSM (27.8% vs 19.5%; P < 0.001), CCI-LR (14.1 vs 7.5%; P < 0.001), DMFS (57.9% vs 65.8%; P = 0.004), and post-DM (12.2% vs 20.1%; P = 0.012), but not in CCI-DM. CONCLUSIONS: Increased adoption of preoperative treatments and greater availability of medical agents in the recent years were associated to better outcomes. New treatments are eagerly awaited for further improvement of outcome for ESTSTS patients because no major changes have been observed since 2003.

Weekly cisplatin with or without imatinib in advanced chordoma: A retrospective case-series analysis from the Italian Rare Cancers Network.

BACKGROUND: To report on a retrospective case-series analysis of weekly cisplatin (wCDDP) as a single agent or combined with imatinib (wCDDP/I) in patients with advanced chordoma treated within the Italian Rare Cancer Network. METHODS: Adult patients with a diagnosis of advanced, brachyury-positive chordoma, treated from April 2007 to October 2020 with wCDDP or wCDDP/I were retrospectively identified. Imatinib was withheld at the same time as wCDDP. Response according to Response Evaluation Criteria in Solid Tumors, overall survival (OS), and progression-free survival (PFS) were analyzed. RESULTS: Thirty-three consecutive patients were identified (wCDDP as front-line n = 8 [24.2%]; wCDDP as a further line n = 25 [75.8%]; prior imatinib n = 25 [75.8%]; evidence of progression before starting wCDDP n = 33). Of 32 patients evaluable for response (wCDDP, n = 22 [68.8%]; wCDDP/I, n = 10 [31.3%]), best response was stable disease (SD) in 27 patients (84.3%) and progression in 5 patients (15.6%). At a median follow-up of 54 months, the median OS (m-OS) was 30.3 months (interquartile range [IQR], 18.1-56.6), the m-PFS was 8.0 months (IQR, 5.1-17.0), the 6-month PFS rate was 65.2%, and the 12-month PFS rate was 30.3%. Of 22 patients who received wCDDP, the best response was SD in 18 patients (81.8%) and progression in 4 patients (18.2%), and the m-PFS was 8.0 months (IQR, 5.1-17.0 months). Of 10 patients who received treatment with wCDDP/I, the best response was SD in 9 patients (90%) and progression in 1 patient (10%), and the m-PFS was 9.3 months (IQR, 4.9-26.5 months). CONCLUSIONS: This series suggests that wCDDP, both as a single agent and combined with imatinib, has antitumor activity in chordoma. Although no dimensional responses were observed, 65% and 30% of previously progressive patients were progression-free at 6 and 12 months, respectively. A prospective study is warranted.

Predictive Value of MRP-1 in Localized High-Risk Soft Tissue Sarcomas: A Translational Research Associated to ISG-STS 1001 Randomized Phase III Trial.

MRP-1 is implicated in multidrug resistance and was described as prognostic in high-risk patients with soft-tissue sarcoma (STS) in a previous study. The current research aimed to validate MRP-1 prognostic/predictive value in localized sarcomas treated with anthracyclines plus ifosfamide within the ISG-1001 phase III study. In addition, the inhibitory activity on MRP-1 was investigated in preclinical studies to identify new combinations able to increase the efficacy of standard chemotherapy in STS. MRP-1 expression was assessed by IHC in tissue microarrays from patients with STS and tested for correlation with disease-free survival (DFS) and overall survival (OS). In vitro studies tested the efficacy of MRP-1 inhibitors (nilotinib, ripretinib, selumetinib, and avapritinib) in sarcoma cell lines. The effect of combinations of the most active MRP-1 inhibitors and chemotherapy was measured on the basis of apoptosis. MRP-1 was evaluable in 231 of 264 cases who entered the study. MRP-1 expression (strong intensity) was independently associated with worse DFS [HR, 1.78; 95% confidence interval (CI), 1.11-2.83; P = 0.016], in the multivariate analysis, with a trend for a worse OS (HR, 1.78; 95% CI, 0.97-3.25; P = 0.062). In vitro studies showed that the addition of MRP-1 inhibitors (nilotinib or avapritinib) to doxorubicin plus palifosfamide, significantly increased cell death in SK-UT-1 and CP0024 cell lines. MRP-1 is an adverse predictive factor in localized high-risk patients with STS treated with neoadjuvant anthracyclines plus ifosfamide followed by surgery. In vitro findings support the clinical assessment of the combination of chemotherapy and MRP-1 inhibitors as a promising strategy to overcome the drug ceiling effect for chemotherapy.

Oncological outcomes after major vascular resections for primary retroperitoneal liposarcoma.

BACKGROUND: The surgical management of retroperitoneal sarcomas frequently involves complex multivisceral resections, however retroperitoneal liposarcoma (LPS) rarely invade major abdominal vessels. The aim of the study was to assess association of major vascular resections with outcome of primary LPS. METHODS: All consecutive patients who underwent resection at our institutions for primary LPS between 2002 and 2019 were included. A propensity matched analysis was performed, adjusting the groups for the variables of Sarculator, to assess the effect of vascular resection on oncological outcomes. RESULTS: Overall 425 patients were identified. Twenty-four (5%) patients had vascular resection. At final pathology 18 patients had vascular infiltration, 2 vascular encasement and 4 involvement without infiltration. Vascular resection was associated with longer operative time (480' vs. 330'; p < 0.001) and greater need for transfusions (4 vs. 0 units; p < 0.001), and was burdened by a higher rate of major complications (54% vs. 25%; p = 0.002). After propensity matched analysis, patients undergoing vascular resection had a lower 5-year OS (60% vs. 81%; p = 0.05), and a higher incidence of local and distant recurrence at 5 years (local: 45% vs. 24%, p = 0.05; distant: 20% vs. 0%, p = 0.04). CONCLUSIONS: Vascular resection is feasible and safe even in the context of multivisceral resection for primary retroperitoneal liposarcomas, although associated to a higher complication rate. However, the independent association between vascular involvement and a higher risk of local recurrence, distant metastases and death may imply a more aggressive biology, which should be factored in the initial management of this complex disease.

Mechanisms of responsiveness to and resistance against trabectedin in murine models of human myxoid liposarcoma.

Myxoid liposarcoma (MLPS) is a rare soft-tissue sarcoma characterised by the expression of FUS-DDIT3 chimera. Trabectedin has shown significant clinical anti-tumour activity against MLPS. To characterise the molecular mechanism of trabectedin sensitivity and of resistance against it, we integrated genomic and transcriptomic data from treated mice bearing ML017 or ML017/ET, two patient-derived MLPS xenograft models, sensitive to and resistant against trabectedin, respectively. Longitudinal RNA-Seq analysis of ML017 showed that trabectedin acts mainly as a transcriptional regulator: 15 days after the third dose trabectedin modulates the transcription of 4883 genes involved in processes that sustain adipocyte differentiation. No such differences were observed in ML017/ET. Genomic analysis showed that prolonged treatment causes losses in 4p15.2, 4p16.3 and 17q21.3 cytobands leading to acquired-resistance against the drug. The results dissect the complex mechanism of action of trabectedin and provide the basis for novel combinatorial approaches for the treatment of MLPS that could overcome drug-resistance.

YAP1-TFE3-fused hemangioendothelioma: a multi-institutional clinicopathologic study of 24 genetically-confirmed cases.

YAP1-TFE3-fused hemangioendothelioma is an extremely rare malignant vascular tumor. We present the largest multi-institutional clinicopathologic study of YAP1-TFE3-fused hemangioendothelioma to date. The 24 cases of YAP1-TFE3-fused hemangioendothelioma showed a female predominance (17 female, 7 male) across a wide age range (20-78 years old, median 44). Tumors were most commonly located in soft tissue (50%), followed by bone (29%), lung (13%), and liver (8%), ranging from 3 to 115 mm in size (median 40 mm). About two-thirds presented with multifocal disease, including 7 cases with distant organ metastasis. Histopathologically, we describe three dominant architectural patterns: solid sheets of coalescing nests, pseudoalveolar and (pseudo)vasoformative pattern, and discohesive strands and clusters of cells set in a myxoid to myxohyaline stroma. These patterns were present in variable proportions across different tumors and often coexisted within the same tumor. The dominant cytomorphology (88%) was large epithelioid cells with abundant, glassy eosinophilic to vacuolated cytoplasm, prominent nucleoli and well-demarcated cell borders. Multinucleated or binucleated cells, prominent admixed erythrocytic and lymphocytic infiltrates, and intratumoral fat were frequently present. Immunohistochemically, ERG, CD31, and TFE3 were consistently expressed, while expression of CD34 (83%) and cytokeratin AE1/AE3 (20%) was variable. CAMTA1 was negative in all but one case. All cases were confirmed by molecular testing to harbor YAP1-TFE3 gene fusions: majority with YAP1 exon 1 fused to TFE3 exon 4 (88%), or less commonly, TFE3 exon 6 (12%). Most patients (88%) were treated with primary surgical resection. Over a follow-up period of 4-360 months (median 36 months) in 17 cases, 35% of patients remained alive without disease, and 47% survived many years with stable, albeit multifocal and/or metastatic disease. Five-year progression-free survival probability was 88%. We propose categorizing YAP1-TFE3-fused hemangioendothelioma as a distinct disease entity given its unique clinical and histopathologic characteristics in comparison to conventional epithelioid hemangioendothelioma.

Dedifferentiation within well-differentiated liposarcoma of the extremity or trunk: Implications for clinical management.

BACKGROUND: In extremity or trunk liposarcoma, the implications of a dedifferentiated (DD) component within a well-differentiated (WD) tumor are unclear. We evaluated outcomes after surgery and identified potential predictors of survival in these patients compared to those with an entirely WD tumor. METHODS: Retrospective data were collected for patients who underwent complete resection from 2009 to 2019. Cumulative incidences of local recurrence (LR) and distant metastasis (DM) were calculated, and overall survival (OS) was estimated. Associations between OS and clinicopathologic variables were evaluated by univariable models. RESULTS: A total of 210 patients with MDM2-verified tumors were studied, including 58 (27.6%) with DD. In primary disease, LR occurred only in DD and worse OS was observed versus WD (p < 0.001). In recurrent disease, the LR incidences were similar between WD and DD (p = 0.559); however, worse OS persisted in DD (p = 0.004). The incidence of DM was extremely low (3.8%) and limited to DD. Higher grade (p < 0.001) and DD size (p = 0.043), but not overall tumor size were associated with worse OS. CONCLUSIONS: In extremity or trunk liposarcoma, the presence of DD leads to significantly worse outcomes in both primary and recurrence diseases. Further study is needed to determine if these patients benefit from adjunct therapies (e.g., radiation).

Molecular Determinants of Soft Tissue Sarcoma Immunity: Targets for Immune Intervention.

Soft tissue sarcomas (STSs) are a family of rare malignant tumors encompassing more than 80 histologies. Current therapies for metastatic STS, a condition that affects roughly half of patients, have limited efficacy, making innovative therapeutic strategies urgently needed. From a molecular point of view, STSs can be classified as translocation-related and those with a heavily rearranged genotype. Although only the latter display an increased mutational burden, molecular profiles suggestive of an "immune hot" tumor microenvironment are observed across STS histologies, and response to immunotherapy has been reported in both translocation-related and genetic complex STSs. These data reinforce the notion that immunity in STSs is multifaceted and influenced by both genetic and epigenetic determinants. Cumulative evidence indicates that a fine characterization of STSs at different levels is required to identify biomarkers predictive of immunotherapy response and to discover targetable pathways to switch on the immune sensitivity of "immune cold" tumors. In this review, we will summarize recent findings on the interplay between genetic landscape, molecular profiling and immunity in STSs. Immunological and molecular features will be discussed for their prognostic value in selected STS histologies. Finally, the local and systemic immunomodulatory effects of the targeted drugs imatinib and sunitinib will be discussed.