Undifferentiated Sarcoma Research Articles

Pediatric Hepatic Cystic Lesions: Differential Diagnosis and Multimodality Imaging Approach.

When a pediatric hepatic cystic lesion is identified at imaging, the differential diagnosis may be broad, including developmental, infectious, neoplastic, and posttraumatic or iatrogenic causes. The location of a cystic lesion and its number, size, composition, and relationship to the biliary system are features that help in narrowing the differential diagnosis. An incidentally detected simple hepatic cyst is the most commonly encountered. Ciliated foregut cysts are typically located in hepatic segment IVa. The presence of multiple cysts should raise suspicion for fibropolycystic liver disease, a group of related lesions-including biliary hamartoma and choledochal cyst-caused by abnormal embryologic development of the ductal plate. Communication of the cystic lesion with the biliary tree can confirm the diagnosis of choledochal cyst. In a neonate with jaundice, a cystic lesion at the porta hepatis should raise suspicion for choledochal cyst versus cystic biliary atresia. Hepatic abscess can appear cystlike, though typically with internal contents. In an immunocompromised child, multiple cystlike lesions should raise concern for fungal microabscesses. A complex cystic mass in a young child should raise suspicion for mesenchymal hamartoma, which can evolve into undifferentiated embryonal sarcoma if untreated. Hepatic hematoma and biloma can appear cystlike in children with a history of trauma or recent intervention. In neonates with an umbilical vein catheter (UVC), an intrahepatic cyst along the course of the UVC should raise concern for infusate extravasation. Familiarity with imaging findings and clinical features is essential for achieving accurate diagnosis of pediatric hepatic cystic lesions, which in turn can guide appropriate clinical management. Online supplemental material is available for this article. ©RSNA, 2022.

Neoadjuvant transcatheter arterial chemoembolization and systemic chemotherapy for the treatment of undifferentiated embryonal sarcoma of the liver in children.

BACKGROUNDUndifferentiated embryonal sarcoma of the liver (UESL) is a rare and aggressive mesenchymal tumor in children. Herein, we describe our experience in neoadjuvant therapy (NAT) and subsequent surgery for the treatment of UESL in children.AIMTo evaluate the efficacy of NAT and explore a new choice for successful operation of UESL in children.METHODSWe retrospectively analyzed six patients newly diagnosed with unresectable UESL who received NAT and then surgery at our center between January 2004 and December 2019. The tumor was considered unresectable if it involved a large part of both lobes of the liver or had invaded the main hepatic vessels or inferior vena cava. The NAT included preoperative transcatheter arterial chemoembolization (TACE) and systemic chemotherapy. The patients were 4 boys and 2 girls with a mean age of 7 years. The longest tumor at presentation ranged from 8.6 to 14.8 cm (mean, 12 cm). Extrahepatic metastases were present in 2 cases. Preoperative systemic chemotherapy was administered 3 wk after TACE. Tumor resection was performed 3 wk after one or two cycles of NAT. The patients received systemic chemotherapy after surgery.RESULTSAll patients successfully underwent NAT and complete resection. The tumor volumes decreased by 18.2%–68.7%, with a mean decrease of 36% after 1 cycle of NAT (t = 3.524, P = 0.017). According to the Response Evaluation Criteria In Solid Tumors criteria, 4 patients had a partial response and underwent surgery, while 2 had stable disease and received another cycle of NAT before surgery. Massive tumor necrosis was seen on pathological examination of the surgical specimen: > 90% necrosis in two, > 50% necrosis in three, and 25% necrosis in 1, with an average of 71.8%. Post-NAT complications included fever, nausea and vomiting, and mild bone marrow suppression. Elevated alanine transaminase levels occurred in all patients, which returned to normal within 7–10 d after treatment. No cardiac or renal toxicity, severe hepatic dysfunction, bleeding and non-target embolization were observed in the patients. The median follow-up period was 8 years with an overall survival of 100%.CONCLUSIONNAT effectively reduced tumor volume, cleared the tumor margin, and caused massive tumor necrosis. This may be a promising choice for successful surgery of UESL in children.

Plocabulin, a Novel Tubulin Inhibitor, Has Potent Antitumour Activity in Patient-Derived Xenograft Models of Soft Tissue Sarcoma.

A clinically relevant subset of patients with soft tissue sarcoma presents with either locally advanced or upfront metastatic disease, or will develop distant metastases over time, despite successful treatment of their primary tumour. The currently available systemic agents to treat such advanced cases only provide modest disease control and are not active in all histological subtypes. Thus, there is an unmet need for novel and more efficacious agents to improve the outcome of this rare disease. In the current preclinical in vivo study, we evaluated plocabulin, a novel tubulin inhibitor, in five distinct histological subtypes of soft tissue sarcoma: dedifferentiated liposarcoma, leiomyosarcoma, undifferentiated sarcoma, intimal sarcoma and CIC-rearranged sarcoma. The efficacy was tested in seven patient-derived xenograft models, which were generated by the engraftment of tumour fragments from patients directly into nude mice. The treatment lasted 22 days, and the efficacy of the drug was assessed and compared to the doxorubicin and vehicle groups by volumetric analysis, histopathology and immunohistochemistry. We observed tumour volume control in all the tested histological subtypes. Additionally, in three sarcoma subtypes, extensive central necrosis, associated with significant tumour regression, was seen. This histological response is explained by the drug’s vascular-disruptive properties, reflected by a decreased total vascular area in the xenografts. Our results demonstrate the in vivo efficacy of plocabulin in the preclinical models of soft tissue sarcoma and corroborate the findings of our previous study, which demonstrated similar vascular-disruptive effects in gastrointestinal stromal tumours—another subtype of soft tissue sarcoma. Our data provide a convincing rationale for further clinical exploration of plocabulin in soft tissue sarcomas.

Adult NTRK-rearranged spindle cell neoplasms of the viscera: with an emphasis on rare locations and heterologous elements

AbstractNTRK-rearranged mesenchymal neoplasms mostly affect the soft tissues of pediatric patients. Given the responsiveness to selective NTRK inhibitors, it remains critical to identify those ultra-rare cases occurring in the viscera of adults. In five females and two males aged 18–53 years, we characterized visceral mesenchymal tumors harboring TPM3-NTRK1 [uterine cervix (N = 2), pleura, prostate], LMNA-NTRK1 (lung), SQSTM1-NTRK3 (heart), and NTRK3 rearrangement with unknown fusion partner (colon/mesocolon) with RNA sequencing, FISH, RT-PCR, and immunohistochemistry. The tumors exhibited spindled to ovoid/epithelioid or pleomorphic cells, often arranged in fascicles, and were low-to-intermediate-grade and high-grade in three and four cases, respectively. Keloid-like stromal collagen and perivascular hyalinization was noted in five. Adenosarcoma-like appearances were observed in two, manifesting frond-like protrusions in one cervical tumor and phyllodes-like architecture in the prostatic tumor. Abrupt high-grade transformation into pleomorphic liposarcoma was found in another cervical tumor, while the pleural tumor contained intermixed rhabdomyoblasts. Pan-TRK immunostaining was positive in all cases. All cases expressed CD34, while five were S100-positive. CDKN2A homozygous deletion with concomitant p16 loss occurred in 4/7. Whole-exome sequencing identified TP53 mutation (c.672+2T>C, involving a splice site, with concomitant protein loss) in a cervical sarcoma, limited to its heterologous liposarcomatous component. At least moderate pan-TRK immunoreactivity was present in varying proportions of potential pathologic mimics, with BCOR-positive sarcoma (56%, 5/9), undifferentiated uterine sarcoma (50%, 3/6), and spindle cell/sclerosing rhabdomyosarcoma (33%, 2/6) being among the most frequent. This underscored the unsatisfactory specificity of pan-TRK immunohistochemistry and warranted molecular confirmation in the diagnosis of adult NTRK-rearranged visceral mesenchymal neoplasms. The current report highlights the ever-expanding clinicopathologic and genetic spectrum of this entity by describing the unprecedented cardiac and pleural locations and heterologous differentiation, as well as the second NTRK-rearranged “prostatic stromal sarcoma,” while substantiating CDKN2A deletion as a frequent occurrence.

Safety and feasibility of laterally extended endopelvic resection for sarcoma in the female genital tract: a prospective cohort study.

ObjectiveThis study aims to evaluate the safety and feasibility of laterally extended endopelvic resection (LEER) for sarcoma in the female genital tract.MethodsWe prospectively recruited gynecologic cancer patients with sarcoma arising from female genital tract who underwent LEER at Seoul National University Hospital from December 2016 to March 2021. Clinicopathologic characteristics, surgical outcomes including postoperative complications and pain control, and survival outcomes of the patients were investigated.ResultsA total of nine patients were registered for this study. The median age was 56 years. Carcinosarcoma (n=2, 22%), leiomyosarcoma (n=2, 22%), and undifferentiated uterine sarcoma (n=2, 22%) were common histology types. Complete resection was achieved in 88.9%. The most common location of pelvic sidewall tumors was infra-iliac acetabulum (66.7%). The pathologic outcome showed a median tumor size of 9.0 cm and internal iliac vessel resection with pelvic sidewall muscle was performed in all patients. The median estimated blood loss was 1,600 mL (range, 300–22,300), and the patients were postoperatively admitted to the intensive care unit for median 1 day (range, 0–8). Complete response was observed in 44.4% (4/9) in radiologic studies after LEER, and median progression-free survival, treatment-related survival, and overall survival were 3.3, 19.6, and 98.9 months, respectively.ConclusionLEER was feasible and safe in treating recurrent sarcoma presenting pelvic sidewall invasion with acceptable survival outcomes and manageable postoperative complications.

CIC-DUX4 sarcomas.

CIC-DUX4 sarcoma (CDS) is a high-grade undifferentiated round cells sarcoma that belongs to the undifferentiated round cell sarcomas family. It represents less than one percent of sarcomas, defining a rarest among rare malignancies. It affects young adults, displaying soft tissue mass. Considered very aggressive, a high proportion of cases display an advanced disease with lung metastasis at diagnosis. Here we discuss recent progress in molecular characterization of CDS, the main tracks of CDS biology and the current and future prospects of therapeutic approaches. CDS is characterized by a specific oncogenic translocation CIC::DUX4 that induce ETV4 overexpression. Patients with CDS show an aggressive clinical course and have a significantly unfavorable outcome compared to Ewing sarcoma. As of today, there is a lack of consensus on whether they should be treated with an Ewing-like approach, as currently done by most sites, or regarded as high-grade soft tissue sarcoma (STS). Anyway, when feasible, combination regimens including anthracycline and alkylating agents should be favored and patients should not benefit from a therapeutic de-escalation. Overall, registration within clinical trials and prospective registries is recommended. Overall, CDS showed a poor prognosis regardless of the patterns of treatment that warrant biological studies to better understand the disease.

Undifferentiated Hepatic Sarcoma: A Rare Case

Primary hepatic undifferentiated pleomorphic sarcoma (UPS) is a rare malignant mesenchymal tumor with a nonspecific clinical and radiologic presentation. Primary hepatic UPS is often a diagnosis of exclusion made by multiple immunohistological testing that rules out hepatic, hematologic, neural, and epithelial origin. Stains for mesenchymal origin are usually the only positive stain and do not demonstrate evidence of specific mesenchymal cell differentiation. We report a case of a 56-year-old male with no significant past medical history that presented with complaint of epigastric abdominal pain of six months duration. A computed tomography (CT) scan of the abdomen and pelvis exhibited numerous hepatic masses involving right and left hepatic lobe. A CT-guided core needle biopsy discovered undifferentiated/pleomorphic sarcoma. Histomorphology showed spindle cell neoplasm without recognizable hepatic tissue. Immunohistochemistry (IHC) stains were positive for smooth muscle actin (SMA) but failed to establish a more specific histogenesis. Furthermore, IHC stains revealed spindle neoplastic cells with focal and patchy positive h-caldesmon (approximately 10-15% of neoplastic cells), and negative for desmin. Given these results, the diagnosis of undifferentiated/pleomorphic sarcoma was established. It is imperative to consider UPS in the differential diagnosis of large liver lesions without evidence of differentiation. Early identification of this rare tumor can prevent the possibility of distant metastasis and improve survival among patients.

"Malignant Mesenchymoma" Revisited: A Clinicopathologic Study of Leiomyosarcomas With Osteosarcomatous Differentiation.

Leiomyosarcoma (LMS) is the most common sarcoma in adults. Rarely, LMS dedifferentiates into an undifferentiated sarcoma. Very few cases of LMS with heterologous osteosarcomatous differentiation (OS) have been reported. The purpose of this study was to evaluate the clinicopathologic features of LMS with OS. Of 5570 LMS cases diagnosed from 2006 to 2022, 15 cases (0.2%) of LMS with OS were identified, affecting 13 females and 2 males; ages ranged from 32 to 66 years (median: 53y). Ten tumors arose in the uterus, 2 in the retroperitoneum, and 1 each in the mesentery, mediastinum, and rectum. Primary tumors ranged from 7 to 20cm (mean: 16cm). The LMS components showed conventional spindle cell morphology in most cases; 3 cases showed marked pleomorphism; 3 cases contained an epithelioid component; and 1 case showed myxoid features. In 5 cases OS was identified in the primary tumor, whereas in 10 cases OS was first detected in metastases. One metastatic and 2 primary LMS showed both OS and chondrosarcomatous differentiation. Prominent osteoclastic giant cells were seen in the OS components in 11 cases. Mitotic activity ranged from 17 to 61/10HPF with tumor necrosis in 10 cases. Twelve patients developed metastases; sites included lungs, diaphragm, kidney, adrenal glands, colon, small intestine, liver, bone, and pancreas. At last follow-up, 8 patients had died of disease, and 4 patients were alive with metastases. The interval between OS and death ranged from 3 weeks to 18 months (median: 6.5mo). Development of OS in LMS is exceptionally rare. This form of heterologous differentiation may occur in both primary tumors and metastases. LMS with OS is highly aggressive with poor outcomes. Awareness of this phenomenon is important to avoid misdiagnosis as osteosarcoma.

Clinical and Pathologic Characterization of 94 Radiation-Associated Sarcomas: Our Institutional Experience.

Radiation-associated sarcomas are an uncommon complication of therapeutic radiation. However, their prevalence has increased with the more widespread use of this treatment modality. The clinical, pathologic and genetic characteristics of radiation-associated sarcomas are not fully understood. In this study we describe the features of 94 radiation-associated sarcomas reviewed at our institution between 1993 and 2018, evaluate their overall survival (OS) and progression-free survival (PFS) outcomes, and compare them with their sporadic counterparts reviewed within the same time period. Histologic subtypes of all radiation-associated sarcomas included 31 (33%) undifferentiated sarcomas, 20 (21%) osteosarcomas, 17 (18%) angiosarcomas, 10 (11%) malignant peripheral nerve sheath tumor (MPNST), 9 (10%) leiomyosarcomas, 4 (4%) myxofibrosarcomas, and 3 (3%) rhabdomyosarcomas. Six patients had a documented cancer predisposition syndrome. The most common preceding neoplasms included adenocarcinoma (47%) and squamous cell carcinoma (19%), with a mean latency of 13 years. Multivariable Cox survival analysis demonstrated that advanced stage at diagnosis based on pT category (AJCC eighth edition) and fragmented resection were associated with worse survival outcomes. In addition, there was a statistically significant difference in PFS between radiation-associated undifferentiated sarcomas and MPNST when compared to their sporadic counterparts using the Kaplan-Meier method and Log-rank analysis. Overall, our study shows that radiation-associated sarcomas comprise a wide clinico-pathologic spectrum of disease, with a tendency for aggressive clinical behavior. This study further delineates the understanding of these uncommon diseases. Future studies are necessary to better understand the genetic and epigenetic changes that drive the differences in behavior between these tumors and their sporadic counterparts, and to offer better treatment options.

ETMR-03. Intra- and extra-cranial BCOR-ITD tumours are separate entities within the BCOR-rearranged family

BCOR-ITD tumours form an emerging family of aggressive entities with an internal tandem duplication (ITD) in the last exon of the BCOR gene. The family includes cerebral tumours, termed central nervous system BCOR-ITD (CNS BCOR-ITD), and sarcomatous types described in the kidney as clear cell sarcoma of the kidney (CCSK), in the endometrium as high-grade endometrial stromal sarcoma (HG-ESS), in bone, and in soft tissue as undifferentiated round cell sarcoma (URCS) or primitive myxoid mesenchymal tumour of infancy (PMMTI). Based on a series of 33 retrospective cases, including 10 CNS BCOR-ITD and 23 BCOR-ITD sarcomas, we interrogated the homogeneity of the entity regarding clinical, radiological and histopathological findings, and molecular signatures. Whole transcriptomic sequencing and DNA methylation profiling were used for unsupervised clustering. Histopathological review revealed marked differences between CNS BCOR-ITD and BCOR-ITD sarcomas. These two groups were consistently segregated by unsupervised clustering of expression (n=22) and DNA methylation (n=21) data. Proximity between the two groups may result from common somatic changes within key pathways directly related to the novel activity of the ITD itself. Conversely, comparison of gene signatures with single-cell RNAseq atlases suggests that the distinction between BCOR-ITD sarcomas and CNS BCOR-ITD may result from differences in cells of origin.

Molecular features of undifferentiated sarcoma of soft tissue and carcinoma.

e23519 Background: Both undifferentiated sarcoma of soft tissue and undifferentiated carcinomas can arise in multiple tissue and are with an aggressive clinical course. While undifferentiated sarcomas that remain a diagnosis of exclusion and show extreme genomic complexity, less is known about undifferentiated carcinoma. Methods: Sixty-two patients diagnosed as undifferentiated sarcoma (n = 36, 10 bone/limbs, 9 abdomen, 9 pelvis, and 8 chest/intrathoracic) or carcinoma (n = 26, excluding undifferentiated carcinoma of nasopharynx and thyroid, 15 chest/intrathoracic, 8 abdomen, and 3 pelvis) were recruited in the study. Mutational analysis was performed by next-generation sequencing of 1021 tumor related genes, which enabled analysis of TMB and MSI as well. PD-L1 expression data was available in 24 patients. Results: Fifty-eight patients (93.5%, 58/62) had at least 1 mutation identified and 542 SNV, 115 CNV and 5 fusions were identified in total in the 62 patients. The top 5 mutant genes were TP53 (56.5%, 35/62), TERT (11.3 %, 7/62), SMARCA4 (9.7%, 6/62), LRP1B (9.7%, 6/62), and MLL2 (9.7%, 6/62). Interestingly, mutation in TP53 was more common in undifferentiated carcinoma (73.08%, 19/26) than sarcoma (44.44%, 16/36, p = 0.0377). Two ERBB2 CNV and 1 KIF5B-RET fusion were identified in 2 gastric carcinoma and 1 lung large cell carcinoma. However, no carcinoma but 2 sarcoma (1 polymorphic undifferentiated sarcoma in the limb and 1 undifferentiated small round cell sarcoma in the lung) showed MSI-H, with TMB as high as 22.08 and 65.28 respectively, while the median TMB was 3.84 mutations/Mb. Among the 24 patients with PD-L1 data, 16 were > 1%, and 5 were > 50%, with no significant difference between undifferentiated carcinoma and sarcoma. Conclusions: In spite of the genome complexity in undifferentiated sarcoma of soft tissue and carcinoma, there was limited actionable mutations in these two aggressive tumors. However, immunotherapy should be considered since over half of these patients were PD-L1 positive and nearly a quarter of them had high PD-L1 expression.

Phase I study of pegylated liposomal doxorubicin in combination with cyclophosphamide and vincristine in pediatric patients with relapsed/refractory sarcoma and other malignant solid tumors.

11519 Background: Pegylated liposomal doxorubicin (PLD) was found to have improved toxicity profile, especially with regards to reduced cardiotoxicity. The objectives of this study were to determine the maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D) of PLD in combination with cyclophosphamide and vincristine (PCV regimen) and describe the toxicities and response of this regimen. Methods: This was an open-label, single-center, single-arm phase I study utilizing a “3 + 3” design. The primary endpoint was the MTD of PLD, and the secondary endpoints included safety, objective response rate (ORR), disease control rate (DCR), and progression-free survival (PFS). Efficacy was evaluated using RECIST 1.1. PFS was defined as the time from treatment until disease progression or death. This study included cohort A and cohort B. Three dose levels were studied in cohort A, PLD 30 mg/m2 (L1), 40 mg/m2 (L2) or 50 mg/m2 (L3) d1 + cyclophosphamide and mesna at 1 g/m2/d d1-2 + vincristine 1.5 mg/m2/d (≯2mg) d1 every 3 weeks. As the endpoint of the study could not be reached, we changed the dose of cyclophosphamide and mesna to 1.5 g/m2/d d1 in cohort B. Results: Eleven in cohort A and 34 in cohort B were enrolled, the median age was 6 years (range 1-15). Forty-three patients were eligible and evaluable for toxicity, and 35 (77.8%) patients were evaluable for response. Diagnoses were rhabdomyosarcoma (n = 29, 64.4%), Ewing's sarcoma (n = 4), and others. The median number of prior regimens was 2 (range 1-5). The most common adverse event (AE) was grade 3 or grade 4 neutropenia with a proportion of 90.9% and 65.5% in cohort A and cohort B, respectively. There was no significant difference in ORR (60% vs. 48%) and DCR (90% vs. 88%) between the two cohorts. The ORR (60% vs. 0, P = 0.019) and DCR (96.7% vs. 40%, P = 0.006) were significantly higher in Group 1 (rhabdomyosarcoma, Ewing's sarcoma, Wilm's tumor, fibrosarcoma, undifferentiated sarcoma) compared with Group 2 (neuroblastoma, osteosarcoma, embryonal sarcoma, epithelioid sarcoma, extrarenal rhabdoid tumor). The 12-month PFS of Group 1 was also better than Group 2 (79% vs. 60%, P = 0.041). Conclusions: The PCV regimen demonstrated an acceptable toxicity profile and promising clinical efficacy in pediatric patients with R/R rhabdomyosarcoma, Ewing's sarcoma, Wilm's tumor, fibrosarcoma, and undifferentiated sarcoma. Increasing the dose of cyclophosphamide did not improve the efficacy, but increased the toxicity. The RP2D for future studies is PLD 30 mg/m2/d for one day. Clinical trial information: NCT04213612. [Table: see text]

Excess of blood TNFa-R as a sign of recurrence of G1 soft tissue sarcomas in older men and G3 soft tissue sarcomas in older women.

11556 Background: Tumor necrosis factor alpha (TNFa) and its receptor (TNFa-R) play an important role in tumor genesis. However, their involvement in the recurrence of sarcomas is poorly studied. The purpose of this study was to analyze levels of TNFa and TNFa-R in the blood of patients with recurrent soft tissue sarcomas. Methods: The study included 64 male and female patients, mean age 63.4±5.2 years. Main groups included patients with recurrent G1 and G3 soft tissue sarcomas T2bN0M0; comparison groups included patients with primary G1 and G3 soft tissue sarcomas T2bN0M0. 95% of tumors were liposarcomas, with solitary rhabdamyosarcomas, myxofibrosarcomas, epithelioid and undifferentiated sarcomas. All recurrent patients had previously underwent surgical and radiation treatment for primary sarcomas and their relapses (up to 2 episodes), with the last surgery more than 1 year ago. Control groups (n = 10 each) included healthy donors of similar age. Levels of TNFa and TNFa-R were measured in the blood serum by ELISA before the treatment. Results: No significant differences were found between TNFa levels in patients with primary and recurrent soft tissue sarcomas and in donors. Levels of TNFa-R in men with primary G3 sarcomas were 1.5 times (p < 0.05) higher compared with donors, 1.7 times (p < 0.05) higher than in men with primary G1 sarcomas, and 1.3 times (p < 0.05) higher than in women with primary G3 sarcomas. TNFa-R increased by 1.7 times (p < 0.05) in all men with recurrent sarcomas regardless of the tumor grade, compared with the levels in healthy men; however, in G1 it was 1.9 times (p < 0.05) higher than in men with primary G1 sarcomas, while in G3 it did not differ significantly from the levels in men with primary G3 sarcomas. TNFa-R in women increased only in recurrent G3 sarcomas by 2.5 times compared to healthy women. No differences were observed in TNFa-R levels between men and women with recurrent G3 sarcomas. Conclusions: An excess of TNFa-R in the blood is characteristic for the recurrent soft tissue sarcomas G1 in older men and G3 in older women. At the same time, high grade tumors in men are accompanied by an increase in TNFa-R in the blood in both primary and recurrent sarcomas.

Epidemiological and demographic characteristics of gynecological sarcoma: Results of the prospective intergroup registry for gynecological sarcoma in Germany (REGSA–NOGGO RU1).

e17630 Background: Gynecological sarcomas (GS) are orphan diseases associated with poor prognosis. With the aim to improve our understanding of GS, the German registry for gynecological sarcoma (REGSA) prospectively recorded patients’ data with GS treated in real-life clinical practice at initial diagnosis and the time of relapse. Herein, we present the analysis of demographic and epidemiological data of patients with GS at the time of initial diagnosis. Methods: An exploratory analysis among different histological subtypes of GS was performed and patients’ data were compared to data of the healthy standard population. We analyzed the following variables: age, body mass index (BMI), Eastern Cooperative Oncology Group (ECOG) performance status, ethnicity, lifestyle habits, pregnancies, and comorbidities. Results: Data of 389 patients with GS were descriptively evaluated. Leiomyosarcoma (LMS) was the most common histological subtype (47.3%), followed by low-grade endometrial stromal sarcoma (LG-ESS; 17.7%), high-grade ESS (HG-ESS; 10.4%), adenosarcoma (AS; 9.1%) and undifferentiated uterine sarcoma (UUS; 6.2%). Overall, 9.4% of all GS were classified as “other” rarer histological subtypes. The mean age of patients was 57.4 years. The youngest were the patients with LG-ESS (54.3 years), whereas patients with AS were the oldest ones (61.7 years). There were no statistically significant differences in average age nor in BMI among patients with different histological subtypes of GS. In contrast, compared to the standard population, the BMI of patients with GS was significantly higher (27.5 kg/m² vs 25.1 kg/m², p< 0.001). Overall, 70.7% of all patients with LMS had FIGO stage I or II. Therefore, it is not surprising that most of patients had ECOG performance status 0 (68.3%). According to the countries of recruitment (i.e. Germany, Austria, Switzerland), 92.8% of patients were Caucasian. REGSA patients were less likely to be smokers compared to the national average of German women (13.4% vs 18.6%). One or two births per patient were reported in 58.2% of patients. In comparison the current birth ratio in Germany is approximately 1.5 children per woman. Hypertension was the most common comorbidity as observed in 33.2% of all cases, followed by thyroid diseases (18.6%). The prevalence of hypertension in the German female standard population is approximately 30% and approximately every third person will be affected by thyroid diseases in their lifetime. Conclusions: REGSA data showed no statistically significant differences in terms of demographic variables between different histological subtypes of GS, whereas statistically significant difference such as BMI was identified as compared to the standard population. Further research is needed to specify risk factors of GS in order to promote primary prevention of this fatal disease.

Prevalence of ultra-rare undifferentiated round cells sarcoma of bone and soft tissue after genomic classification.

11559 Background: Over the last decade, the category of undifferentiated round cell sarcomas (URCS), defined by the absence of Ewing sarcoma-associated translocations, has emerged. Aim of this study was to assess prevalence of each entity and outcome after genomic classification. Methods: Ewing sarcoma and other URCS diagnosed between 1920 and 2020 were reviewed. All URCS with available material were analyzed with FISH, RT-qPCR and/or Archer FusionPlex Sarcoma Panel. Demographic and treatment were collected. Survival was analyzed in patients with available follow-up. Results: 1995 cases identified, 20 cases lacked material for further genetic analysis and were excluded. 1975 cases were classified as follows: 1925 Ewing sarcomas (97.47%), 25 CIC-rearranged sarcomas (1.27%), 16 BCOR-CCNB3 rearranged sarcomas (0.81%), 2 EWSR1-NFATC2 sarcoma (0.1%), one each as CIC-LEUTX and FUS-NFATC2 rearranged sarcoma (0.05% each), and 5 as unclassified URCS (0.25%). A different presentation according to tumor type was shown in 43/50 ultra-rare tumors (Table). Forty-one/50 cases had available follow-up: 20/41 patients underwent surgery, 14/41 surgery+radiotherapy, 6 radiotherapy only, and no local treatment for 1 patient. Chemotherapy was administrated to 36/41 patients (Ewing sarcoma drugs in 16/22 CIC-DUX-4 and 8/11 BCOR-CCNB3; osteosarcoma drugs in 2/11 BCOR-CCNB3, and doxorubicin/ifosfamide in 2/22 CIC-DUX4 and 2/5 URCS; not specified in 6 cases). The 3-years overall survival (OS) was 32.7%f for CIC-rearranged sarcomas (75% in localize disease, 7,7% for the advanced disease, p 0.0084), 81.8% for BCOR-CCNB3 sarcomas (87.5% localized, 66.7% advanced; p 0.0734), and 60% for URCS (p 0.057). 1 patient with CIC-LEUTX sarcoma presenting with metastases died 13 months from diagnosis, 1 patient with FUS-NFATC2 and 1 with EWSR1-NFATC2 rearrenged sarcomas were alive without disease at 8 and 5 years from onset. Conclusions: Prevalence of URCS characterized by a combination of morphologic observation ad molecular techniques is provided. The majority of the cases underwent surgery or surgery combined with radiotherapy, and Ewing-like chemotherapy. The survival difference among different entities underscores the need of accurate subclassification of round cell sarcomas. Novel drugs for CIC-DUX-4 sarcomas presenting with metastases are needed. [Table: see text]

In vitro evidence that combination treatment with anti-PD-1 and anti-CD47 immunotherapy may not be efficient in human soft tissue sarcoma.

e23560 Background: Soft tissue sarcomas (STSs) are rare mesenchymal tumors. With more than 70 histological subtypes of STSs, studies defining robust biomarkers of therapeutic value are lacking. Even with the improvements in local control rates, metastases and death occur in 50% of patients that are diagnosed with high-risk STSs. Across nearly all sarcoma types, macrophages dominate the immune landscape of STSs. While immune checkpoint inhibitors (ICIs) represent the major immunotherapeutic approach in malignancies with a high load of T cells, the anti-CD47 anti-cancer therapy mostly promotes macrophage-mediated phagocytosis. The efficacy of both therapies is critically dependent on the composition of the tumor microenvironment. Methods: In our study, we evaluated the potential additive effects of combining the anti-PD-1 immunotherapy and anti-CD47 immunotherapy ex vivo. The proportions of tumor cells and tumor-infiltrating lymphocytes were characterized ex vivo from resected tumors of 73 patients who underwent surgery for STS. The expression of CD47 on tumor cells was analyzed by immunohistochemistry. Cell suspensions were obtained from freshly resected tumors and the proportions of CD45+, CD45-, CD3+, CD4+, and CD8+ cells were measured by flow cytometry. The effect of the anti-PD-1 blockade, anti-CD47 blockade, and the combinatorial application of anti-PD-1 and anti-CD47 therapies on the immune cell activation in vitro was investigated by culturing of cell suspensions at a concentration 0.3x106/ul in the presence/absence of therapeutic monoclonal antibody (Nivolumab 2 ug/ml; anti-CD47 clone MIAP410 20ug/ml) and evaluated by a cytokine Luminex assay (Milliplex® MAP Human Cytokine Bead Panel (Sigma Aldrich) for TNFα, IFNγ, and IL-2 cytokines analysis). Results: The addition of anti-PD1 to CD3/CD28 stimulation drastically increased the production of all cytokines analyzed. This increase in pro-inflammatory cytokine secretion was even more pronounced after adding an anti-CD47 monoclonal antibody to the cell culture. However, a combinatorial application of anti-PD-1 and anti-CD47 agents in vitro was found to limit rather than potentiate the immune activation in the TME of human STS. On an individual level, the most profound response to anti-PD-1 was observed in high-grade leiomyosarcoma and the most profound response to anti-CD47 therapy was observed in an undifferentiated pleiomorphic sarcoma. Conclusions: Our data suggest that combinatorial strategies based on ICIs and anti-CD47 blockade may not provide the desired outcome in STSs. Both therapies, anti-PD-1, and anti-CD47 alone, could however bear a therapeutic potential in selected tumors after close evaluation of the CD47 and PD-1 expression status, as well as the extent of T cell/macrophage infiltration.

Single-cell RNA-seq of a soft-tissue sarcoma model reveals the critical role of tumor-expressed MIF in shaping macrophage heterogeneity.

SUMMARYThe standard of care is unsuccessful to treat recurrent and aggressive soft-tissue sarcomas. Interventions aimed at targeting components of the tumor microenvironment have shown promise for many solid tumors yet have been only marginally tested for sarcoma, partly because knowledge of the sarcoma microenvironment composition is limited. We employ single-cell RNA sequencing to characterize the immune composition of an undifferentiated pleiomorphic sarcoma mouse model, showing that macrophages in the sarcoma mass exhibit distinct activation states. Sarcoma cells use the pleiotropic cytokine macrophage migration inhibitory factor (MIF) to interact with macrophages expressing the CD74 receptor to switch macrophages’ activation state and pro-tumorigenic potential. Blocking the expression of MIF in sarcoma cells favors the accumulation of macrophages with inflammatory and antigen-presenting profiles, hence reducing tumor growth. These data may pave the way for testing new therapies aimed at re-shaping the sarcoma microenvironment, in combination with the standard of care.

Role of CT and MRI image fusion and computer assisted simulation technique in guiding type Ⅲ and Ⅳ primary pelvic sarcoma surgeries

Objective: To explore the possible clinical benefits of CT/MRI image fusion and computer-assisted simulation techniques in guiding type Ⅲ and Ⅳ primary pelvic bone tumor surgeries. Methods: The clinic data of primary bone sarcomas patients treated at Department of Bone and Soft Tissue,Zhenghzhou University Affiliated Cancer Hospital from January 2019 to December 2021 were retrospectively analyzed. Based on whether the CT and MRI image fusion technique was utilized for tumor evaluation and surgical planning,the patients were divided into image fusion group (n=21) or control group (n=27). There were 7 male and 14 female patients included in the image fusion group, with the age of (37.0±10.4) years(range: 18 to 67 years). In the control group, there were 10 males and 17 females with the age of (39.7±15.2) years (range: 16 to 65 years). Both groups included osteosarcoma,chondrosarcoma and undifferentiated polymorphic sarcoma as the pathological diagnosis. Clinical information such as gender,age,pathological diagnosis,location of disease,and metastasis at diagnosis were collected. Surgical related information such as duration of surgery,blood loss,surgical margin,and wound complications were also obtained. Periodical follow-ups every 3 months were performed for all patients to monitor the status of local recurrence,distant metastasis,and survival information. Independent t test and χ² test were used for data comparison between groups. Results: Significant reduced duration of surgery was observed in the image fusion group in comparison with control group both in type Ⅲ and Ⅳ surgeries ((144.0±31.6)min vs. (248.2±56) min,t=-8.084, P<0.01); (173.0±42.0)min vs. (306.1±62.0)min, t=-4.518, P<0.01). Blood loss was significantly reduced in the image fusion group compared with the control group ((484.8±226.3)ml vs. (836.1±359.8)ml,t=-4.130, P<0.01). In addition, significant lower ratio of R1 margin and recurrence rates of type Ⅲ and Ⅳ surgeries were found in the image fusion group comparing with the control group (4.8%(1/21) vs. 22.2%(6/27), χ²=4.214, P=0.040; 4.8%(1/21) vs. 22.2%(6/27), χ²=4.214, P=0.040).In the image fusion group, there were 3 cases of incision infection, 1 of which underwent secondary debridement.And in thecontrol group there were 7 cases of incision infection, 3 of which underwent secondary debridement. There was no significant difference in the incidence of complications between the two groups (14.2%(3/21)vs. 25.9%(7/27), χ²=0.645, P=0.422). Up to the last follow-up, 1 patient died in the image fusion group and 2 patients died in the control group, the difference was not statistically significant (χ²=1.885, P=0.220). Conclusion: Compared with the traditional operation,the image fusion technique can significantly reduce the duration of surgery,blood loss and lower the recurrence rate by achieving better surgical margins.

Undifferentiated Embryonal Sarcoma of the Liver Involving All Major Hepatic Veins Treated by Left Extended Trisectionectomy

Introduction Over the past few years, liver surgery has been in constant evolution and gained many improvements that helped surgeons push limits further. A complex procedure such as left extended trisectionectomy, as described by Makuuchi in 1987, may be performed in selected cases. Aim Describe a case of successful resection of a huge bilobar liver sarcoma involving all hepatic veins from a young female patient, in which the blood outflow was preserved through an inferior right hepatic vein, leaving only segment 6 as liver remnant. Case Report. A 19-year-old female with a 3-month history of abdominal pain, vomiting, and weight loss was referred for our evaluation. CT scan and MRI revealed a heterogeneous and bulky expansive hepatic lesion, sparing only segment 6, with an estimated volume of 530 cm3, corresponding to a 1.2 FLR/BW ratio. The tumor involved the three major hepatic veins, but an inferior right hepatic vein was present, draining the spared segment 6. She was submitted to a left trisectionectomy extended to the caudate lobe and segment 7, including resection of all hepatic veins and lymphadenectomy of the hepatic pedicle. She was discharged on the 7th postoperative day without complications. The histopathological and immunohistochemical analysis demonstrated an undifferentiated embryonal sarcoma of the liver. Conclusion Inferior right hepatic vein-preserving left extended trisectionectomy is a safe and feasible procedure that should be performed by a hepatobiliary team experienced in major complex hepatectomies.

BCOR-CCNB3 sarcoma with concurrent RNF213-SLC26A11 gene fusion: a rare sarcoma with altered histopathological features after chemotherapy

BackgroundChemotherapy is a common approach for cancer treatment, but intrinsic genetic mutations in different individuals may cause different responses to chemotherapy, resulting in unique histopathological changes. The genetic mutation along with the distinct histopathological features may indicate new tumor entities. BCOR-CCNB3 sarcomas is a kind of Ewing-like sarcomas (ELS) occurring mostly in bone and soft tissues. No gene fusion other than BCOR-CCNB3 has been found in this type of tumor.Case presentationWe herein report a case of 17-year-old male patient, presented with a mass on his left shoulder that was diagnosed as undifferentiated small round cell sarcoma according to core biopsy. The patient received 5 courses of preoperational chemotherapy, and the tumor was resected and analyzed. Primitive small round cells and larger myoid cells in the resected tumor tissue but not in biopsy were observed, and arterioles stenosis and occlusion were also detected, indicating a dramatic change of histopathological features of this tumor. In addition, the immunohistochemical results showed the altered staining patterns of BCOR, bcl2, CyclinD1, TLE1, AR, SMA, CD117, STAB2, CD56, and CD99 in tumor tissues after chemotherapy. Notably, RNA sequencing revealed a RNF213-SLC26A11 fusion in the tumor sample.ConclusionsThe BCOR-CCNB3 sarcoma with RNF213-SLC26A11 fusion may indicate a subset of tumors that undergo histopathological changes in response to chemotherapy. More similar cases in the future may help to clarify the clinical meanings of RNF213-SLC26A11 fusion in BCOR-CCNB3 sarcomas and the underlying mechanisms.