Well-differentiated Liposarcoma Research Articles

Diagnosing liposarcoma on (peri)-renal mass biopsy: A clinicopathological study of 30 cases.

Classification of renal neoplasms on small tissue biopsies is in increasing demand, and maintaining broad differential diagnostic considerations in this setting is necessary. When evaluating a renal or perirenal tumour biopsy with sarcomatoid morphology, together with sarcomatoid renal cell carcinoma and sarcomatoid urothelial carcinoma as top diagnostic considerations, it is vital to additionally consider the possibility of well-differentiated and de-differentiated liposarcoma. This study reports a series of 30 biopsy samples from sites in or around the kidney collected from four institutions in which the correct diagnosis was either well-differentiated or de-differentiated liposarcoma. The majority (26 of 30, 87%) of lesions were accurately diagnosed on biopsy sampling, all of which incorporated testing for MDM2 by immunohistochemistry (IHC), fluorescence in-situ hybridisation (FISH) or a combination of the two as part of the diagnostic work-up. Tumour expression of MDM2 by IHC without confirmatory FISH analysis was sometimes (30%) sufficient to reach a diagnosis, but demonstration of MDM2 amplification by FISH was ascertained in the majority (57%) of biopsy samples. A diagnosis of de-differentiated liposarcoma was not definitively established until resection in four (13%) patients, as no MDM2 testing was performed on the corresponding pre-operative biopsies. When a retroperitoneal tumour is not clinically suspected, histological consideration of a liposarcoma diagnosis may be overlooked. Implementation of ancillary immunohistochemical and cytogenetic testing can ultimately lead to a definitive diagnosis in this potentially misleading anatomical location.

GLI1 Coamplification in Well-Differentiated/Dedifferentiated Liposarcomas: Clinicopathologic and Molecular Analysis of 92 Cases

GLI1(12q13.3) amplification is identified in a subset of mesenchymal neoplasms with a distinct nested round cell/epithelioid phenotype. MDM2 and CDK4 genes are situated along the oncogenic 12q13-15 segment, amplification of which defines well-differentiated liposarcoma (WDLPS)/dedifferentiated liposarcoma (DDLPS). The 12q amplicon can occasionally include GLI1, a gene in close proximity to CDK4. We hereby describe the first cohort of GLI1/MDM2/CDK4 coamplified WD/DDLPS. The departmental database was queried retrospectively for all cases of WD/DDLPS having undergone next-generation (IMPACT) sequencing with confirmed MDM2, CDK4, and GLI1 coamplification. Clinicopathologic data were obtained from a review of the medical chart and available histologic material. Four hundred eighty-six WD/DDLPS cases underwent DNA sequencing, 92 (19%) of which harbored amplification of the GLI1 locus in addition to MDM2 and CDK4. These included primary tumors (n = 60), local recurrences (n = 29), and metastases (n = 3). Primary tumors were most frequently retroperitoneal (47/60,78%), mediastinal (4/60,7%), and paratesticular (3/60, 5%). Average age was 63 years, with a male:female ratio of 3:2. The cohort comprised of DDLPS (86/92 [93%], 6 of which were comprised of WDLPS with early dedifferentiation) and WDLPS without any longitudinal evidence of dedifferentiation (6/92, 7%%). One-fifth (13/86,17%) of DDLPS cases showed no evidence of a well-differentiated component in any of the primary, recurrent, or metastatic specimens. Dedifferentiated areas mostly showed high-grade undifferentiated pleomorphic sarcoma-like (26/86, 30%) and high-grade myxofibrosarcoma-like (13/86, 16%) morphology. A disproportionately increased incidence of meningothelial whorls with/without osseous metaplasia was observed as the predominant pattern in 16/86 (19%), and GLI1-altered morphology as described was identified in a total of 10/86 (12%) tumors. JUN (1p32.1), also implicated in the pathogenesis of WD/DDLPS, was coamplified with all 3 of MDM2, CDK4, and GLI1 in 7/91 (8%) cases. Additional loci along chromosomal arms 1p and 6q, including TNFAIP3, LATS1, and ESR1, were also amplified in a subset of cases. In this large-scale cohort of GLI1 coamplified WD/DDLPS, we elucidate uniquely recurrent features including meningothelial whorls and GLI-altered morphology in dedifferentiated areas. Assessment of tumor location (retroperitoneal or mediastinal), identification of a well-differentiated liposarcoma component, and coamplification of other spatially discrete genomic segments (1p and 6q) might aid in distinction from tumors with true driver GLI1 alterations.

Imaging features of perinephric myxoid pseudotumors of fat.

Retrospectively evaluate multimodality imaging features of perinephric myxoid pseudotumor of fat (PMPTF). Institutional cases of PMPTF with CT, MRI and/or ultrasound evaluation from 1/1/2020 to 9/1/2023 were retrospectively reviewed. Patient demographics and clinical history were reviewed, and imaging features recorded. 14 patients with pathologically-proven PMPTF were identified (11M, 3 F; mean age 66.7 ± 17.0years; range 40-87years). Three patients (18%) had bilateral lesions; a total of 17 PMPTFs were reviewed. 15/17 (88%) were biopsy-proven; two cases were diagnosed by imaging only in patients with a contralateral biopsy-proven PMPTF. All evaluable specimens were negative for MDM2 amplification. 11/17 (65%) occurred in patients with renal disease, including 4/17 (24%) in patients with renal transplant. 100% (17/17) had CT, 11/17 (65%) MRI, and 6/17 (35%) ultrasound. The mean largest lesion dimension was 10.9 ± 4.6cm (range 4.3-17.0cm). Of cases involving native kidneys, 7/13 (54%) presented as multifocal perinephric masses and 5/13 (38%) as a solitary perinephric mass. All four transplant cases presented as infiltrative-appearing masses involving the renal sinus with lesser perinephric involvement. 14/17 (82%) lesions contained macroscopic fat on CT and MRI and 3/17 (18%) showed no macroscopic fat, all involving renal transplants. All cases with MRI demonstrated T2 hyperintensity with signal dropout on opposed-phase imaging. 11/13 (85%) PMPTF showed no or equivocal CT enhancement. Enhancement was better seen on MRI in all cases evaluated by both CT and MRI. Of the six PMPTFs imaged by ultrasound, four (67%) were heterogeneously hypoechoic and two (33%) had mixed regions of hypo-, iso- and hyperechogenicity relative to adjacent renal parenchyma. PMPTF is a rare, benign, and underrecognized lesion that may mimic malignancy, particularly retroperitoneal well-differentiated liposarcoma. The imaging features of this unusual pseudosarcoma differ in native and transplanted kidneys. Improved awareness of this entity will facilitate appropriate patient management and avoid unnecessary intervention.

Intense FDG Uptake in Well-Differentiated Inflammatory Liposarcoma of the Retroperitoneum.

Inflammatory variant of well-differentiated liposarcoma is a rare subtype of liposarcoma, and its imaging features have been rarely reported. We describe FDG PET/CT findings in a case of well-differentiated inflammatory liposarcoma. The tumor showed no detectable fat and intense FDG uptake and caused diffuse FDG uptake of the bone marrow due to paraneoplastic leukemoid reaction. Microscopically, there were extensive inflammatory infiltrates in the tumor, which may contribute to the intense FDG uptake. This case indicates that although well-differentiated liposarcoma usually shows low-grade FDG uptake, inflammatory variant of well-differentiated liposarcoma can show intense FDG uptake mimicking high-grade liposarcoma.

Surgical management of urethral obstruction secondary to perineal liposarcoma in a dog: a case report

BackgroundSwelling of the perineal region in male dogs is most commonly caused by a perineal hernia. Clinical signs associated with perineal hernia are constipation, tenesmus or stranguria. This case report documents a rare cause of perineal swelling created by the growth of a malignant tumour leading to urethral obstruction and subsequent stranguria.Case presentationAn 11-year-old neutered male German Shepherd was presented for swelling in the perineal region and stranguria for three days. Complete blood count and serum biochemistry were unremarkable. Ultrasound revealed a heterogeneous mass in the perineal region. Retrograde urethrography showed a severe narrowing of the urethra caudal to the pelvis. A fine-needle aspirate of the mass was highly suspicious for liposarcoma. Staging was performed by computed tomography (CT) of the thorax and abdomen. Total penile amputation in combination with pubic-ischial pelvic osteotomy, transposition of the remaining urethra through the inguinal canal, V-Y-plasty cranial to the prepuce and preputial urethrostomy were performed to remove the tumour. Histopathology confirmed a well-differentiated liposarcoma with complete histological margins. Six months after the surgery the dog was doing well and there were no signs indicating local tumour recurrence.ConclusionsWide surgical excision is generally recommended for soft tissue sarcomas, however this is sometimes not feasible for large tumours. In the case reported here, tumour resection was achieved by a combination of several surgical techniques with a good clinical outcome.

Abstract 4425: Metabolic vulnerabilities of dedifferentiated liposarcoma

Abstract Dedifferentiated liposarcoma (DDLPS) is a rare, life-threatening malignancy in the family of adipocytic sarcomas. DDLPS, which usually arises in the retroperitoneum of middle-aged adults, has a poor prognosis. This is due to the propensity of DDLPS to metastasize and recur locally, combined with a dearth of effective systemic therapies. A longstanding curiosity is that DDLPS has non-lipogenic morphology and no lipid droplets, while its less aggressive sister sarcoma, well-differentiated liposarcoma (WDLPS), resembles benign adipose tissue and contains large lipid droplets. How DDLPS metabolizes lipids and the metabolic vulnerabilities of DDLPS in patients, which may form new therapeutic targets, are unknown. In our project, we investigate the metabolism of DDLPS versus WDLPS using patient samples and cell lines. Snap-frozen tissues from patients were obtained from the Dana-Farber/Harvard Cancer Center specimen bank of DDLPS and WDLPS. We performed metabolomics and lipidomics on these samples. We complemented these results with publicly available transcriptional profiles of separate cohorts of DDLPS, WDLPS, and other cancers. In vitro, we made use of a panel of multiple DDLPS-derived cell lines, WDLPS-derived cells, benign preadipocytes, and benign adipocytes. We measured mitochondrial function and the cellular effects of perturbing various metabolites in screens in culture. Overall, our initial results indicate strong alterations in mitochondrial metabolism in DDLPS in patients. In culture, DDLPS is susceptible to multiple metabolic perturbations related to mitochondrial dysfunction. These metabolic vulnerabilities of DDLPS provide potential therapeutic opportunities. Work is ongoing to optimize the targeting of these vulnerabilities in vivo, elucidate the molecular roles of specific metabolites, and complete a blueprint of DDLPS metabolic weaknesses in patients. Citation Format: Jamie O. Brett, Ji Seul Han, Choah Kim, Liam P. Kelley, SeongJun Han, Dylan Boone, Joseph Crowley, Shakchhi Joshi, Chandrajit P. Raut, Anna Greka, Marcia C. Haigis. Metabolic vulnerabilities of dedifferentiated liposarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4425.

Abstract 604: Targeting casein kinase 1 alpha (CK1 alpha) and transcriptional CDKs (CDK7/9) in human liposarcomas

Abstract Introduction: Liposarcomas (LPS) are rare mesenchymal cell malignancies of adipocytic origin that are diagnosed in more than 3500 patients in the US each year. The two most common subtypes, well-differentiated LPS (WDLPS) and dedifferentiated LPS (DDLPS), are characterized by extrachromosomal DNA amplifications harboring the MDM2 (100%) and CDK4 (90+%) genes, generally with wild type TP53. Management of metastatic or surgically unresectable LPS remains purely palliative. Recent clinical trials targeting MDM2 or CDK4/6 with small-molecule inhibitors have shown promise but have been hampered by dose-limiting toxicities. The development of new therapeutics is greatly needed to improve outcomes for patients with LPS. Results: To identify unique liposarcoma-specific vulnerabilities, we screened multiple human LPS cell lines for transcriptional CDK expression and found high levels of CDK7 and CDK9. We demonstrate that CDK9 inhibitors suppress LPS cell growth and induce apoptosis by decreasing MDM2 levels while inducing expression of p53. To enhance p53 activation in these cells, we screened for expression of known regulators of p53, including CK1α, whose inhibition has previously been shown to activate p53. We demonstrate that LPS cells express CK1α and that the cytotoxic effects of CDK9 inhibitors are enhanced upon CK1α depletion. These data led us to examine combined targeting of CK1α and CDK9 in LPS with the novel agent BTX-A51, which has previously been shown to inhibit CK1α, CDK9, as well as CDK7 with nanomolar efficacy in AML models. BTX-A51 potently reduces expression of MDM2 with marked induction of p53, resulting in profound apoptosis of LPS cells. Through CRISPR/Cas9-mediated p53 knockout, we establish that BTX-A51-mediated apoptosis is primarily p53-dependent. However, BTX-A51 also reduces expression of MCL1 and primes LPS cell lines and primary LPS cells for BIM-induced apoptosis, as demonstrated by BH3 profiling. Importantly, preliminary in vivo data in an LPS patient-derived xenograft model reveal that BTX-A51 is well-tolerated with tumor growth inhibition. Conclusions: Our results suggest that BTX-A51 has potent preclinical efficacy in treating LPS, primarily through inhibition of CK1α and CDK9. Future mechanistic studies will further clarify mechanisms of BTX-A51-mediated apoptosis, as well as the contribution of CDK7 inhibition to anti-tumor activity. Our data justify a planned clinical trial that will evaluate the efficacy of BTX-A51 in patients with advanced WDLPS or DDLPS. Citation Format: Renyan Liu, Nicole L. Solimini, Patrick Bhola, Timothy B. Branigan, Jie Hao, Xin Wang, Roshen Alharthi, Michael Yorsz, Shaili Soni, Cing-siang Hu, Irit Snir-Alkalay, Prafulla Gokhale, Anthony Letai, Yinon Yinon Ben-Neriah, George D. Demetri, Geoffrey I. Shapiro. Targeting casein kinase 1 alpha (CK1 alpha) and transcriptional CDKs (CDK7/9) in human liposarcomas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 604.

Abstract 4337: Illuminating the complex rearrangement landscape of sarcoma

Abstract Structural rearrangements and in particular, gene fusions, are key mutational processes in bone and soft tissue tumors, used for both disease classification and as biomarkers. However, the mutational processes and rearrangement processes underlying many of these events remain poorly characterized. Recent data indicate that sarcomas show particularly high frequencies of complex rearrangement events, including patterns which do not fit those of known mutational mechanisms. As the largest whole genome sequencing (WGS) cohort of sarcomas to date, the Genomics England (GE) 100,000 Genomes project represents a unique dataset in which to profile these events. Structural variants (SVs) were identified in whole genome sequencing data for 978 samples from the Genomics England 100,000 Genomes Project using an optimized approach based on 5 specialized SV callers. SVs identified by at least 2 callers were filtered to retain only those which passed the quality filter, and to remove variants present in either matched germline samples or >1% of a panel of normal variants. Chromothriptic events, extrachromosomal DNA (ecDNA) and genes enriched for SVs were identified using established algorithms. The prevalence of SVs varies across sarcoma, in keeping with previous reports, with particularly high rates observed in myxofibrosarcoma and liposarcoma. As described previously, liposarcomas showed the highest rates of chromothripsis. We have examined some tumor types at higher granularity than previously available, demonstrating directly that the rates of complex rearrangement events vary across subtypes. For example, chromothriptic events are identified in 100% of well-differentiated liposarcomas, but less than 10% of myxoid liposarcomas. Similarly, the presence of ecDNA varies by tumor type, with the novel observation of particularly high rates in angiosarcoma. Using these data, we have catalogued the rearrangement patterns generating canonical gene fusions in fusion-driven soft tissue tumor types. Despite more recent advances in histological classification, survival for patients with sarcoma has remained largely unchanged for 40 years. Characterization of the mutational processes underlying these rearrangements will shed light on the pathogenesis of these tumors. Citation Format: Sara Waise, Tom Lesluyes, Jonas Demeulemeester, Maxime Tarabichi, Adrienne Flanagan, Nischalan Pillay, Peter Van Loo. Illuminating the complex rearrangement landscape of sarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4337.

Surgical Management of a Large Well-Differentiated Liposarcoma in the Supraclavicular Fossa: A Case Report.

Background: Liposarcomas originating in the supraclavicular fossa are exceptionally rare, with only a few documented cases in the medical literature. Methods: We present a unique case involving a remarkably large indolent, atypical lipomatous tumor or well-differentiated liposarcoma situated in the right supraclavicular region, measuring 18 cm × 18 cm × 17 cm. To our knowledge, this represents the largest liposarcoma found in the supraclavicular fossa reported in the literature. This unique case highlights the effective management of a remarkably large supraclavicular liposarcoma through complete surgical resection. Result and Conclusion: Our findings further support the existing consensus that complete surgical removal is often curative for well-differentiated liposarcoma.

Giant pelvic well-differentiated liposarcoma

Herein, we report a case of a giant well-differentiated liposarcoma located subgluteally and extending into the pelvis through the obturator foramen, nearby the urinary bladder and rectum without causing functional disturbances. The tumor was removed simultaneously with transgluteal posterior and anterior transabdominal approach. Six months postoperatively, no clinical and radiological evidence of recurrence was observed.

Toward the use of diffuse reflection spectroscopy for intra-operative tissue discrimination during sarcoma surgery.

Accurately distinguishing tumor tissue from normal tissue is crucial to achieve complete resections during soft tissue sarcoma (STS) surgery while preserving critical structures. Incomplete tumor resections are associated with an increased risk of local recurrence and worse patient prognosis. We evaluate the performance of diffuse reflectance spectroscopy (DRS) to distinguish tumor tissue from healthy tissue in STSs. DRS spectra were acquired from different tissue types on multiple locations in 20 freshly excised sarcoma specimens. A -nearest neighbors classification model was trained to predict the tissue types of the measured locations, using binary and multiclass approaches. Tumor tissue could be distinguished from healthy tissue with a classification accuracy of 0.90, sensitivity of 0.88, and specificity of 0.93 when well-differentiated liposarcomas were included. Excluding this subtype, the classification performance increased to an accuracy of 0.93, sensitivity of 0.94, and specificity of 0.93. The developed model showed a consistent performance over different histological subtypes and tumor locations. Automatic tissue discrimination using DRS enables real-time intra-operative guidance, contributing to more accurate STS resections.

Diagnostic importance of P16 in the differential diagnosis of well-differentiated liposarcoma and lipomas

Diagnostic importance of P16 in the differential diagnosis of well-differentiated liposarcoma and lipomas

Clinical, Diagnostic, and Treatment Characteristics of Orbital Liposarcoma

PurposeTo clarify the clinical, diagnostic and treatment characteristics of orbital liposarcoma. DesignRetrospective observational case series. MethodsReview of electronic medical records, histopathology, radiological images and follow-up information of 21 patients with orbital liposarcoma. ResultsThe predominant clinical manifestation of this disease was painless exophthalmos. The most frequently encountered pathological types were well-differentiated and myxoid liposarcoma. Preoperative radiological images from 15 patients showed that orbital liposarcoma initially developed in extraocular muscle in 9 patients. Furthermore, all well-differentiated liposarcomas exhibited the radiographic characteristics of irregular and ill-defined adipose tissue, whereas only 12.5% of myxoid liposarcomas had the imaging characteristics. For the patients who exclusively underwent surgery, all cases with subtotal excisions experienced recurrence, 63.6% of marginal excisions recurred and 50% of wide excisions resulted in recurrence. However, none of the patients who underwent marginal excisions or wide excisions combined with adjuvant radiotherapy exhibited recurrence. The analysis of MRI findings in three patients who underwent neoadjuvant radiotherapy revealed that the tumor size remained stable in a patient with well-differentiated liposarcoma, while another patient with the same type of tumor exhibited a gradual increase in size. Conversely, a patient with myxoid liposarcoma experienced a significant reduction in tumor size following neoadjuvant radiotherapy. ConclusionOrbital liposarcoma demonstrated a propensity for developing in the extraocular muscle. The radiological images of well-differentiated liposarcomas were characterized by irregular and ill-defined adipose tissue. Surgery combined with radiotherapy demonstrates potential in reducing recurrence rates. Notably, orbital myxoid liposarcoma exhibited greater sensitivity to radiotherapy compared to well-differentiated liposarcoma.

A giant liposarcoma originating from peripancreatic fat tissue with identification using 3D-CT angiography: a case report

BackgroundLiposarcoma originating from peripancreatic fat tissue is extremely rare. This case report presents a surgical case of a giant liposarcoma originating from peripancreatic fat tissue with origin identification using 3-Dimensional Computed Tomography Angiography (3D-CTA).Case presentationA 59-year-old female was referred to our hospital with a giant abdominal tumor. Computed tomography revealed a 34 cm tumor composed of fatty tissue, exerting pressure on the posterior aspect of the pancreas. Suspecting liposarcoma, we planned for surgery. At first, the tumor appeared to be intra-abdominal tumor, based on the identification of the tumor’s feeding artery as a branch of the dorsal pancreatic artery using 3D-CTA, we concluded that the liposarcoma originated from the peripancreatic fat tissue and situated in the retroperitoneum. During surgery, we observed a well-capsulated, elastic, yellowish mass without infiltration into surrounding tissues. We carefully dissected the tumor from the greater omentum and transverse mesocolon while preserving the tumor capsule. We ligated the feeding artery at the border with the pancreatic parenchyma and successfully completed the excision of the tumor. The resected specimen weighted 2620 g and was pathologically diagnosed as a well-differentiated liposarcoma. There was no injury to the tumor’s capsule, and the surgical margins were negative.ConclusionsIn this report, we present an extremely rare case of a liposarcoma originating in the peripancreatic fat tissue. The use of 3D-CTA was instrumental in identifying the primary site of this giant tumor, enabling us to guide the surgery and achieve complete resection successfully.

Liposarcoma of the testis: A case report

Liposarcoma of the testis is a rare genitourinary tumor. Liposarcoma commonly arises in the spermatic cord and rarely arises in the testis. We describe the case of a 60-year-old man who presented with complaints of swelling, associated with pain, in the right testicular region for 3 weeks. The scrotal ultrasound showed a heterogenous, hyperechoic lesion measuring 10 × 7 cm on the right. The testicular lesion appeared irregularly marginated with heterogeneous echotexture, with a central hyperechoic area and peripheral hypoechogenicity. Contrast-enhanced computed tomography of the abdomen showed no intra-abdominal mass or lymphadenopathy. Tumor markers including alpha-fetoprotein, human chorionic gonadotropin, and lactate dehydrogenase were normal. A right high inguinal orchiectomy was performed, and the postoperative histopathologic examination showed features of liposarcoma of the testis with components of myxoid liposarcoma and well-differentiated liposarcoma. There was no evidence of recurrence up to 4 years post-surgery. Thus, misdiagnosis is common in liposarcoma testis due to the rarity and vague presentation. Ultrasound and tumor makers are often negative. A high index of suspicion is required in cases of tumor marker-negative testicular masses. The treatment of choice is high inguinal orchiectomy; evidence for the utility of chemotherapy and radiotherapy is limited.

CASE-SB-01 - A Case of a Well-differentiated Primary Pericardial Liposarcoma: a Rare Cardiac Tumor with a Favorable Prognosis

CASE-SB-01 - A Case of a Well-differentiated Primary Pericardial Liposarcoma: a Rare Cardiac Tumor with a Favorable Prognosis

Giant liposarcoma of the thigh: A case report

Liposarcoma is a tumor derived from primitive cells that undergo adipose differentiation. They comprise 10%–35% of all soft tissue sarcomas. We present a 46-year-old female patient with a 4-year history of a giant swelling on the lateral aspect of the left thigh. Wide local excision of the mass was performed and histopathological analysis revealed a well-differentiated liposarcoma. Liposarcomas commonly appear in the extremities and have distinct features on imaging studies. Surgical treatment and histology are the most important prognostic factors for patients with lipomatous tumors, as complete surgical excision reduces local recurrence rate.

Multi-omics joint analysis revealed the metabolic profile of retroperitoneal liposarcoma.

Retroperitoneal liposarcoma (RLPS) is the main subtype of retroperitoneal soft sarcoma (RSTS) and has a poor prognosis and few treatment options, except for surgery. The proteomic and metabolic profiles of RLPS have remained unclear. The aim of our study was to reveal the metabolic profile of RLPS. Here, we performed proteomic analysis (n = 10), metabolomic analysis (n = 51), and lipidomic analysis (n = 50) of retroperitoneal dedifferentiated liposarcoma (RDDLPS) and retroperitoneal well-differentiated liposarcoma (RWDLPS) tissue and paired adjacent adipose tissue obtained during surgery. Data analysis mainly revealed that glycolysis, purine metabolism, pyrimidine metabolism and phospholipid formation were upregulated in both RDDLPS and RWDLPS tissue compared with the adjacent adipose tissue, whereas the tricarboxylic acid (TCA) cycle, lipid absorption and synthesis, fatty acid degradation and biosynthesis, as well as glycine, serine, and threonine metabolism were downregulated. Of particular importance, the glycolytic inhibitor 2-deoxy-D-glucose and pentose phosphate pathway (PPP) inhibitor RRX-001 significantly promoted the antitumor effects of the MDM2 inhibitor RG7112 and CDK4 inhibitor abemaciclib. Our study not only describes the metabolic profiles of RDDLPS and RWDLPS, but also offers potential therapeutic targets and strategies for RLPS.

MDM2 FISH testing criteria in adipose tissue tumors with mature adipocytic morphology-A resection case-based study

The current criteria for utilizing MDM2 Fluorescence In Situ Hybridization (FISH) in adipose-derived tumors were first introduced in 2015 and have been widely adopted. However, these criteria may fail to identify some atypical lipomatous tumors / well-differentiated liposarcoma (ALT/WDL) with mature adipocytic morphology in clinical practice, possibly due to the fact that the existing criteria are primarily based on biopsy cases. Hence, a criterion based on resection cases is needed. In this study, we included 87 adipose tissue tumors with mature adipocytic morphology which were first resected, as well as 9 consultation cases and 25 recurrent resection cases. The final diagnosis was based on MDM2 amplification status. Among the 87 first-time resection cohort, MDM2 FISH amplification was observed in only 2 (5%) of the 39 superficial cases. Marginal infiltration was significantly different in both the MDM2 FISH negative and positive groups (p<0.05). Of the 37 intramuscular tumors, 17 (46%) showed MDM2 FISH amplification. The MDM2 amplification positive group had a larger tumor size than MDM2 amplification negative group (p=0.042). Tumors of larger size (≥11cm) were highly correlated with MDM2 amplification (p=0.003), but still, 35.3% of the MDM2 amplification-positive cases had tumor sizes less than 11cm. Eight (66.7%) out of twelve retroperitoneal/ pelvic cases were MDM2 FISH positive. Among the 25 recurrent cases, twenty (80%) of them had MDM2 FISH amplification. In conclusion, we recommend MDM2 FISH for: 1. superficial cases with marginal infiltration based on adequate margin sampling; 2. all intramuscular tumors, retroperitoneal/pelvic tumors and recurrent tumors, both in resection cases and biopsy cases.

Lipid profiling of electrosurgical vapors for real-time assistance of soft tissue sarcoma resection.

Soft tissue sarcomas (STS) constitute a heterogeneous group of rare tumor entities. Treatment relies on challenging patient-tailored surgical resection. Real-time intraoperative lipid profiling of electrosurgical vapors by rapid evaporative ionization mass spectrometry (REIMS) may aid in achieving successful surgical R0 resection (i.e., microscopically negative-tumor margin resection). Here, we evaluate the ex vivo accuracy of REIMS to discriminate and identify various STS from normal surrounding tissue. Twenty-seven patients undergoing surgery for STS at Maastricht University Medical Center+ were included in the study. Samples of resected STS specimens were collected and analyzed ex vivo using REIMS. Electrosurgical cauterization of tumor and surrounding was generated successively in both cut and coagulation modes. Resected specimens were subsequently processed for gold standard histopathological review. Multivariate statistical analysis (principal component analysis-linear discriminant analysis) and leave-one patient-out cross-validation were employed to compare the classifications predicted by REIMS lipid profiles to the pathology classifications. Electrosurgical vapors produced during sarcoma resection were analyzed in vivo using REIMS. In total, 1200 histopathologically-validated ex vivo REIMS lipid profiles were generated from 27 patients. Ex vivo REIMS lipid profiles classified STS and normal tissues with 95.5% accuracy. STS, adipose and muscle tissues were classified with 98.3% accuracy. Well-differentiated liposarcomas and adipose tissues could not be discriminated based on their respective lipid profiles. Distinction of leiomyosarcomas from other STS could be achieved with 96.6% accuracy. In vivo REIMS analyses generated intense mass spectrometric signals. Lipid profiling by REIMS is able to discriminate and identify STS with high accuracy and therefore constitutes a potential asset to improve surgical resection of STS in the future.