Abstract Background Retroperitoneal liposarcoma (RPLS) is known for its propensity for local recurrence and short survival time. We aimed to identify a credible and specific prognostic biomarker for RPLS. Methods Cases from The Cancer Genome Atlas (TCGA) sarcoma dataset were included as the training group. Co-expression modules were constructed using weighted gene co-expression network analysis (WGCNA) to explore associations between modules and survival. Survival analysis of hub genes was performed using the Kaplan–Meier method. In addition, independent external validation was performed on a cohort of 135 Chinese RPLS patients from the REtroperitoneal SArcoma Registry (RESAR) study (NCT03838718). Results A total of 19 co-expression modules were constructed based on the expression levels of 26,497 RNAs in the TCGA cohort. Among these modules, the green module exhibited a positive correlation with overall survival (OS, p = 0.10) and disease-free survival (DFS, p = 0.06). Gene set enrichment analysis showed that the green module was associated with endocytosis and soft-tissue sarcomas. Survival analysis demonstrated that NINJ1, a hub gene within the green module, was positively associated with OS (p = 0.019) in the TCGA cohort. Moreover, in the validation cohort, patients with higher NINJ1 expression levels displayed a higher probability of survival for both OS (p = 0.023) and DFS (p = 0.012). Multivariable Cox analysis further confirmed the independent prognostic significance of NINJ1. Conclusions We here provide a foundation for the establishment of a consensus prognostic biomarker for RPLS, which should not only facilitate medical treatment but also guide the development of novel targeted drugs.

Background Exploring predictive biomarkers and therapeutic strategies of ICBs has become an urgent need in clinical practice. Increasing evidence has shown that ARID1A deficiency might play a critical role in sculpting tumor environments in various tumors and might be used as pan-cancer biomarkers for immunotherapy outcomes. The current study aims to explored the immune-modulating role of ARID1A deficiency in Hepatitis B virus (HBV) related hepatocellular carcinoma (HBV-HCC) and its potential immunotherapeutic implications. Methods In the current study, we performed a comprehensive analysis using bioinformatics approaches and pre-clinical experiments to evaluate the ARID1A regulatory role on the biological behavior, and immune landscape of Hepatitis B virus (HBV) related hepatocellular carcinoma (HBV-HCC). A total of 425 HBV-related hepatocellular carcinoma patients from TCGA-LIHC, AMC and CHCC-HBV cohort were enrolled in bioinformatics analysis. Immunohistochemical staining of HBV-HCC specimens and ARID1A deficiency cellular models were used to validate the results of the analysis. Results Our results have shown that ARID1A deficiency promoted tumor proliferation and metastasis. More importantly, ARID1A deficiency in HBV-HCC was associated with the higher TMB, elevated immune activity, and up-regulated expression of immune checkpoint proteins, especially TIM-3 in HBV-HCC. Further, the expression of Galectin-9, which is the ligand of TIM-3, was elevated in the ARID1A knockout HBV positive cell line. Conclusion To conclude, we have shown that the ARID1A deficiency was correlated with more active immune signatures and higher expression of immune checkpoints in HBV-HCC. Additionally, the present study provides insights to explore the possibility of the predictive role of ARID1A in HBV-HCC patients responsive to immunotherapy.

Introduction: No druggable targets and prognostic factors are currently available for retroperitoneal liposarcoma (RPLS) due to very limited understanding of its molecular mechanisms and pathogenesis. This study aims to decipher expression profiling and prognostic value of aspartate-β-hydroxylase (ASPH), an activator of Notch signaling pathway, in RPLS. Methods: Totally 138 patients with RPLS who received resection were recruited in this retrospective study. Immunohistochemistry was performed to decipher expression profiling of ASPH in archived specimens. Prognostic value of ASPH was evaluated by Kaplan-Meier plot and Cox proportional hazards model. Chi-square test was used to compare counting data. Results: The overall positive rate of ASPH expression in RPLS was 90.6%. Well-differentiated liposarcoma had a similar positive rate to dedifferentiated liposarcoma (90.2% vs. 91.1%). A high level of ASPH expression correlated with reduced postoperative recurrence-free survival rate and overall survival rate (P<0.05). Conclusions: ASPH is an independent predictor for clinical outcome of patients with RPLS. A high level of ASPH expression confers poor post-operational prognosis.

Background Complete resection (CR) serves as the standard of surgical treatment for retroperitoneal liposarcoma (RPLS). Unfortunately, even at referral centers, recurrence rates are high, and CR may not address multifocal diseases, which are a common phenomenon in RPLS. We sought to retrospectively compare the clinical outcomes of RPLS patients treated with total (ipsilateral) retroperitoneal lipectomy (TRL) and CR. Because TRL remove potentially multifocal tumors in the fat, patients may have a better prognosis than CR. Methods Patients with primary/first-recurrent RPLS who had been treated at 5 referral centers were recruited from December 2014 to June 2018. Multivariable Cox regression analyses were conducted to determine the effects of demographic, operative, and clinicopathological variables on the following primary endpoints: local recurrence (LR), local recurrence-free survival (LRFS), and overall survival (OS). Results A total of 134 patients were enrolled in this retrospective study, 53 of whom underwent TRL, and 81 of whom underwent CR. The 2 groups were comparable in terms of age, gender, presentation (primary vs. first-recurrent RPLS), number of tumors (unifocal vs. multifocal) at presentation, and Fédération Nationale des Centres de Lutte Contre le Cancer (FNCLCC) grade. The TRL group had higher levels of preoperative hemoglobin (Hb) (13 vs. 12.5 g/dL; P=0.008) and a lower amount of intraoperative blood loss (400 vs. 500 mL; P=0.034), but there were no significant differences in the length of hospital stay (23 vs. 22 d; P=0.47) or complications (32 vs. 30; P=0.82) between the 2 groups. In a subset of patients with multifocal tumors at initial presentation, OS was more prolonged in those treated with TRL than those treated with CR (P=0.0272). Based on the multivariable analysis, primary liposarcoma and a low FNCLCC grade were associated with decreased LR and improved OS. Conclusions TRL is a safe procedure that positively affects the OS of patients with multifocal RPLS. This novel strategy deserves further investigation in prospective studies.

患者男性,52 岁,因右眼眼球突出半年余至我院就诊.既往4年前行同位置肿物切除,外院病理诊断为梭形细胞肿瘤,未行辅助治疗.查体:一般情况好,心肺腹未见明显异常.视力:右眼0. 6,左眼1. 0;眼压:右眼21 mmHg,左眼20 mmHg.右眼球向外、下方移位隆起,鼻侧结膜下见暗红色肿物,双角膜清,前房不浅,Tyndall征阴性,虹膜纹清,瞳孔圆,对光反应存,晶体清,视网膜在位.眼部CT平扫(图1 ):右眼眶内可见三角形软组织密度影,大小4. 8 cm ×3. 3 cm,内部密度欠均,边界较清,视神经受压改变,眼球受压向前突出,邻近骨质未见破坏.双侧眼球对称,大小形态正常,球内玻璃体、晶状体密度正常,眼球均匀光滑,眼外肌无明显增粗,泪腺无增大,视神经及视交叉走行正常,边界清楚,眶尖眶周未见明显异常.

Abstract Background: As the function of ARID1A loss is controversial in liver cancer, we aim to elucidate how this most frequently mutated SWI/SNF gene would affect the biological process in patients with HBV related hepatocarcinoma, a common type of liver cancer in China, and enlighten the therapy strategies. Methods: Mutation and survival data of 425 HBV patients from three cohorts (TCGA-LIHC, AMC, CHCC) was integrated to assess the Tumor mutational burden (TMB), mutation pattern and OS between ARID1A deficiency patients and normal patients. Single-sample gene set enrichment analysis and Wilcox test were performed with expression data from CHCC-HBV patients for immune signatures and genes associated with ARID1A deficiency. Results: The most frequently loss of function mutation or deletion in ARID1A would lead to deficiency in liver cancer patients. We found that EMT and cell cycle related pathway are enriched. In addition, Mesenchymal marker genes were highly expressed in ARID1A deficiency group. These results revealed that ARID1A deficiency is associated with invasion which corresponded to the worse overall survival. However, these HBV-HCC patients with ARID1A loss may have better response to immunotherapy as the TMB was higher in the ARID1A deficiency group as well as the mutation rate in base excision repair pathway which represent an unstable status in the genome. Investigation showed that immune infiltration level, including the CD8 T cell, Cytotoxic cells (Table 1) was increased in ARID1A deficiency group. Meanwhile, the expression of immune checkpoint gene TIM3 were significantly higher in ARID1A loss patients. Conclusion: ARID1A deficiency defined a group of HBV related liver cancer patients who had worse outcome due to promotion in cell migration. However, the higher TMB, higher mutation rate in DNA damage pathway, higher expression of TIM3 and upregulated immune activity suggested that they might be beneficial target for immunotherapy. p value between the ARID1A deficiency group and normal groupImmune infiltration levelCD8 T cells0.037Immune infiltration levelNeutrophils0.029Immune infiltration leveliDC0.045Immune infiltration levelDC0.024Immune infiltration levelCytotoxic cells0.035Immune infiltration levelTgd cells0.036Immune infiltration levelTreg cells0.041Immune infiltration levelM1 macrophage0.024Immune infiltration levelAll immune0.044GSEA for hallmark pathwayE2F_TARGETS0.006GSEA for hallmark pathwayTNFA_SIGNALING_VIA_NFKB<0.001GSEA for hallmark pathwayINFLAMMATORY_RESPONSE<0.001GSEA for hallmark pathwayTGF_BETA_SIGNALING0.017mRNA expressionTIM30.04mRNA expressionIL60.0015mRNA expressionIFNG0.068MutationTMB0.01 Citation Format: Tao Xing, Han Wang, Xiaosong Rao, Guilan Dong, Xuan Gao, Yaping Xu, Xuefeng Xia, Yanfang Guan, Yiran Chen, Jing Zhao, Jun Liang, Li Li, Zhenping Wen. ARID1A deficiency in HBV related hepatocarcinoma patients is associated with upregulated immune activity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2739.

Background: There was increasing evidence showing that ARID1A alterations correlated with higher tumor mutational burden, but there were limited studies focusing on the adaptive mechanisms for tumor cells to survive under excessive genomic alterations. Materials & methods: To further explore the adaptive mechanisms under ARID1A alterations, we performed RNA sequencing in ARID1A knockdown hepatocellular carcinoma cell lines, and demonstrated that decreased expression of ARID1A controlled global ribosomal proteins synthesis. The results were further confirmed by quantitative reverse transcription-PCR and bioinformatic analysis in The Cancer Genome Atlas Liver Hepatocellular Carcinoma database. Conclusion: The present study was the first to demonstrate that ARID1A might be involved in the translation pathway and served as an adaptive mechanism for tumor cells to survive under stress.

Objective To compare the clinicopathological features, differential diagnosis and treatment between perirenal angiomyolipoma (AML) and liposarcoma. Methods Eleven cases of AML and thirty-nine cases of liposarcoma around the kidney from Peking University International Hospital from January 2015 to December 2020 were reviewed in terms of clinical manifestations, imaging examination, pathological morphology, immunophenotype and treatment follow-up. Results The tumors in both groups were close to the kidney, and the imaging signs of renal defect were not distinctive enough to diagnose correctly. Perirenal AML was mainly female (P=0.003), the age of onset was younger than liposarcoma (P 0.05). Conclusions Retroperitoneal perirenal AML and liposarcoma have similar imaging features, and gender, age, tumor number, primary/recurrent character, histomorphology, protein expression and gene amplification detection are helpful to differentiate them. Liposarcoma needs more extensive resection, active treatment and follow-up. DOI: 10.11855/j.issn.0577-7402.2021.08.08

目的 探讨黏液性结直肠腺癌(mucinous colorectal adenocarcinoma,MCA)与非黏液性结直肠腺癌(non-mucinous colorec-tal adenocarcinoma,non-MCA)中程序性死亡蛋白-配体1(programmed death protein-ligand 1,PD-L1)和CD8的表达.方法 收集结直肠腺癌标本106例,其中non-MCA 90例,MCA 16例,采用免疫组化法检测non-MCA和MCA的肿瘤细胞和肿瘤浸润免疫细胞中PD-L1和CD8表达,计算PD-L1和CD8的阳性率,比较non-MCA和MCA中PD-L1和CD8表达的差异.结果 non-MCA组织中PD-L1表达比MCA高(P<0.001),两组肿瘤组织中PD-L1均大部分表达于肿瘤间质的免疫细胞.在non-MCA组中有23％的PD-L1和CD8同时高表达,有48％的PD-L1和CD8同时低表达,7％的PD-L1高表达和CD8低表达,22％的PD-L1低表达和CD8高表达.在MCA组中有40％的PD-L1和CD8同时低表达,60％的PD-L1低表达而CD8高表达.non-MCA与MCA组织中CD8+T细胞的表达,差异无统计学意义.结论 结直肠腺癌中PD-L1主要表达于肿瘤间质的免疫细胞,且non-MCA较MCA高表达PD-L1;部分non-MCA中PD-L1和CD8同时高表达.

目的:探讨生物潜能未定非典型神经纤维瘤(atypical neurofibromatous neoplasm of uncertain biologic potential,ANNUBP)的临床病理特征、免疫表型、分子遗传学改变.方法:分析2014年12月至2020年8月收集于北京大学国际医院病理诊断为非典型或富于细胞性神经纤维瘤14例患者的临床资料,其中7例具有ANNUBP的特征,光镜观察肿瘤细胞形态、免疫表型特征、并进行总结.结果:ANNUBP中男性5例,女性2例,年龄14～44岁(平均年龄27岁,中位年龄27岁);6例位于腹膜后,1例位于头颈部,最大径4.5～21.5 cm,平均11.0 cm,界限较清.镜下肿瘤细胞可见细胞异型性、丰富密集、失去神经纤维瘤结构和/或核分裂像增加(>1/50 HPF和<3/10 HPF);其中4例多次复发,2例进展为恶性外周神经鞘膜瘤(malignant peripheral nerve sheath tumor,MPNST),1例无瘤生存,复发率85.71％(6/7),恶变率28.57％(2/7);S-100、SOX-10、H3K27Me3在7例中均弥漫强表达,1例CD34染色显示网状结构消失,Ki-67增殖指数<2％～5％.结论:ANNUBP是具有较高复发率和恶变率的肿瘤,术后应结予相应的辅助治疗,并密切随访,同时也应避免过度治疗;结合免疫组织化学,有助于其诊断和鉴别诊断.

BACKGROUND:Deep learning algorithms significantly improve the accuracy of pathological image classification, but the accuracy of breast cancer classification using only single-mode pathological images still cannot meet the needs of clinical practice. Inspired by the real scenario of pathologists reading pathological images for diagnosis, we integrate pathological images and structured data extracted from clinical electronic medical record (EMR) to further improve the accuracy of breast cancer classification.METHODS:In this paper, we propose a new richer fusion network for the classification of benign and malignant breast cancer based on multimodal data. To make pathological image can be integrated more sufficient with structured EMR data, we proposed a method to extract richer multilevel feature representation of the pathological image from multiple convolutional layers. Meanwhile, to minimize the information loss for each modality before data fusion, we use the denoising autoencoder as a way to increase the low-dimensional structured EMR data to high-dimensional, instead of reducing the high-dimensional image data to low-dimensional before data fusion. In addition, denoising autoencoder naturally generalizes our method to make the accurate prediction with partially missing structured EMR data.RESULTS:The experimental results show that the proposed method is superior to the most advanced method in terms of the average classification accuracy (92.9%). In addition, we have released a dataset containing structured data from 185 patients that were extracted from EMR and 3764 paired pathological images of breast cancer, which can be publicly downloaded from http://ear.ict.ac.cn/?page_id=1663 .CONCLUSIONS:We utilized a new richer fusion network to integrate highly heterogeneous data to leverage the structured EMR data to improve the accuracy of pathological image classification. Therefore, the application of automatic breast cancer classification algorithms in clinical practice becomes possible. Due to the generality of the proposed fusion method, it can be straightforwardly extended to the fusion of other structured data and unstructured data.

目的:探讨高风险垂体腺瘤的临床病理特征及诊断要点.方法:选取2017年6月至2020年9月北京大学国际医院收治的24例高风险垂体腺瘤患者,进行形态学观察、免疫组织化学染色及基因检测,同时收集患者的临床资料并进行随访,综合分析病理特点与临床特征的相互关系.结果:24例高风险垂体腺瘤中男性14例,女性10例,发病年龄28 ～ 68岁,平均年龄45.4岁,临床表现为鞍区占位或激素分泌异常的症状.肿瘤最大径0.7～4.8 cm,影像学提示侵袭性腺瘤12例.根据固有激素、转录因子和低分子量角蛋白的免疫组织化学染色特点,结合临床症状及血清激素水平进行诊断,其中稀疏颗粒型生长激素细胞腺瘤4例,沉默性促肾上腺皮质激素细胞腺瘤12例,男性泌乳激素细胞大腺瘤6例,多激素PIT-1阳性腺瘤2例.基因检测1例存在GNAS基因突变.14例获得随访资料,2例复发(其中1例因肿瘤复发死亡).结论:高风险垂体腺瘤的诊断应该结合免疫组织化学、血清激素水平及临床症状综合分析,并且需要提示临床复发和进展的风险.

Building upon the clinical evidence supporting that decomposing a pathological image into different components can improve diagnostic value, in this paper we propose a Decomposition-and-Fusion Network (DFNet) for HE-stained pathological image classification. The medical goal of using HE-stained pathological images is to distinguish between nucleus, cytoplasm and extracellular matrix, thereby displaying the overall layouts of cells and tissues. We embed this most basic medical knowledge into a deep learning framework that decomposes a pathological image into cell nuclei and the remaining structures (that is, cytoplasm and extracellular matrix). With such decomposed pathological images, DFNet first extracts independent features using three independent CNN branches, and then gradually merges these features together for final classification. In this way, DFNet is able to learn more representative features with respect to different structures and hence improve the classification performance. Experimental results on two different datasets with various cancer types show that the DFNet achieves competitive performance.

Automatic breast cancer grading methods based on HE stained pathological images can be summarized into two categories. The first category is to use learning-based methods to directly extract the features of the pathological image for breast cancer grading. However, unlike the coarse-grained problem of breast cancer classification, grading of breast Invasive Ductal Carcinoma (IDC) is a fine-grained classification problem. Only using general methods cannot classify IDC well. The second category is to conduct the three evaluation criteria of Nottingham Grading System (NGS) separately, and then integrate the results of the three criteria to obtain the final IDC grading result. However, NGS is only a semi-quantitative evaluation method. The inherent medical motivation of NGS is to grade IDC with the help of nuclei-related features. In this paper, we proposed a nuclei-aware network for IDC grading in pathological images. The entire network achieves an effect similar to the attention mechanism in end-to-end learning, so as to learn fine-grained and nuclei-related feature representations for IDC grading. It should to be pointed out that our method can emphasize custom areas, thus providing a way to model medical knowledge into the network structure. This is different from the general attention mechanism that cannot artificially control the area of attention. Experimental results show that the performance of proposed method is better than the state-of-the-art.

目的 探讨腹膜后恶性孤立性纤维性肿瘤(MSFT)的临床病理特征、治疗和预后.方法 收集1例MSFT患者的临床病理资料,对其临床表现、病理学特征、免疫表型、治疗及预后进行分析.结果 患者女性,59岁,左侧腰部阵发性疼痛,影像学提示腹膜后占位,多器官受压,接受根治性手术切除.肿瘤界限清楚,有包膜,有坏死,肿瘤细胞丰富,细胞核有异型性,核分裂象6个/10HPF,CD34、Bcl-2、STAT6和CD99蛋白均呈阳性表达.结论 腹膜后MSFT确诊主要依靠病理形态学特征和免疫表型.

Breast cancer grading methods based on hematoxylin-eosin (HE) stained pathological images can be summarized into two categories. The first category is to directly extract the pathological image features for breast cancer grading. However, unlike the coarse-grained problem of breast cancer classification, breast cancer grading is a fine-grained classification problem, so general methods cannot achieve satisfactory results. The second category is to apply the three evaluation criteria of the Nottingham Grading System (NGS) separately, and then integrate the results of the three criteria to obtain the final grading result. However, NGS is only a semiquantitative evaluation method, and there may be far more image features related to breast cancer grading. In this paper, we proposed a Nuclei-Guided Network (NGNet) for breast invasive ductal carcinoma (IDC) grading in pathological images. The proposed nuclei-guided attention module plays the role of nucleus attention, so as to learn more nuclei-related feature representations for breast IDC grading. In addition, the proposed nuclei-guided fusion module in the fusion process of different branches can further enable the network to focus on learning nuclei-related features. Overall, under the guidance of nuclei-related features, the entire NGNet can learn more fine-grained features for breast IDC grading. The experimental results show that the performance of the proposed method is better than that of state-of-the-art method. In addition, we released a well-labeled dataset with 3644 pathological images for breast IDC grading. This dataset is currently the largest publicly available breast IDC grading dataset and can serve as a benchmark to facilitate a broader study of breast IDC grading.

目的 探讨乳腺肌样错构瘤(MH)的临床及病理特征,加强病理医生对MH的认识.方法 收集乳腺肌样错构瘤2例,观察其大体、镜下特点及免疫表型特点.结果 2例发病年龄分别为21岁、29岁.肿瘤直径分别为2 cm、1.9cm,肿瘤1例边界清楚,1例边界不清.肿瘤均由不同比例的乳腺腺泡、导管、纤维间质、脂肪组织及肌样细胞束组成.肌样细胞平行或交叉呈束状排列,形成灶性的平滑肌瘤样形态,散在分布于纤维间质之间,部分区域穿插人小叶腺泡间.2例肌样成分均强阳性表达SMA、Desmin和Caldesmon.结论 MH是乳腺错构瘤的少见亚型,以表达平滑肌标记的平滑肌样细胞束为典型特征,易发生漏诊、误诊,诊断时应充分结合临床病史及镜下、免疫组化特点.

Immune checkpoint blockade (ICB) therapy is a treatment strategy for hepatocellular carcinoma (HCC); however, its clinical efficacy is limited to a select subset of patients. Next-generation sequencing has identified the value of tumor mutation burden (TMB) as a predictor for ICB efficacy in multiple types of tumor, including HCC. Specific driver gene mutations may be indicative of a high TMB (TMB-H) and analysis of such mutations may provide novel insights into the underlying mechanisms of TMB-H and potential therapeutic strategies. In the present study, a hybridization-capture method was used to target 1.45 Mb of the genomic sequence (coding sequence, 1 Mb), analyzing the somatic mutation landscape of 81 HCC tumor samples. Mutations in five genes were significantly associated with TMB-H, including mutations in tumor protein 53 (TP53), Catenin®1 (CTNNB1), AT-rich interactive domain-containing protein 1A (ARID1A), myeloid/lymphoid or mixed-lineage leukemia (MLL) and nuclear receptor co-repressor 1 (NCOR1). Further analysis using The Cancer Genome Atlas Liver Hepatocellular Carcinoma database showed that TP53, CTNNB1 and MLL mutations were positively correlated with TMB-H. Meanwhile, mutations in ARID1A, TP53 and MLL were associated with poor overall survival of patients with HCC. Overall, TMB-H and associated driver gene mutations may have potential as predictive biomarkers of ICB therapy efficacy for treatment of patients with HCC.

Liposarcoma is a malignancy of fat that commonly develops in the retroperitoneum (1,2). In this anatomic location, tumors can be low grade, well differentiated (WD) or have an additional high grade, dedifferentiated (DD) component. Entirely WD tumors are typically indolent and do not metastasize, while tumors with a DD component are more aggressive and have distant metastatic potential. WD and DD liposarcoma can be regarded as opposite ends of a spectrum of disease aggressiveness (e.g., lipoma-like WD to rhabdomyoblastic DD) (3). For patients with retroperitoneal (RP) liposarcoma, high resolution, contrast enhanced CT of the abdomen and pelvis is critical as part of the initial evaluation (4). This should be performed if not done already at the time of referral. WD liposarcomas are well-defined round or lobulated masses predominantly composed of macroscopic fat with few, thin septations (5). Non-fatty, soft tissue density areas with a ground glass appearance can occur and typically constitute less than 25% of the tumor (6). DD areas manifest as discrete nodular soft tissue density areas often with good demarcation from surrounding fat and show variable contrast enhancement. Internal septations are thicker (>2 mm) in DD. Calcifications may also be seen and would suggest DD liposarcoma if found in the nonfatty areas. For patients with suspected DD disease, CT of the chest should be obtained as part of staging to rule out distant metastasis to the lungs (4). To confirm the diagnosis of RP liposarcoma, percutaneous core needle biopsy can be performed. Biopsy may not always be necessary, especially in cases in which the radiologic features highly suggest the diagnosis. On histopathologic examination, WD liposarcoma consists of adipocytes of varying size with fibrous septae and interspersed hyperchromatic cells (7). DD areas are typically juxtaposed next to WD areas with an abrupt transition from the adipocytic (WD) to non-adipocytic, high grade appearing areas containing prominent mitotic figures (DD). Both WD and DD liposarcoma have amplification of 12q13-15 which includes several important genes such as MDM2 and CDK4. This molecular feature is considered pathognomonic and can be used for the definitive diagnosis if the histologic features alone are unclear. For all patients with nonmetastatic retroperitoneal liposarcoma, surgery is the mainstay of treatment. However, in the retroperitoneum, tumors are frequently massive in size and can potentially invade critical organs and major blood vessels, making surgery very difficult. Whether due to technical factors (e.g., “positive” margins) or disease biology [e.g., “field defect” (8)], recurrence rates after resection are high and do not plateau over time (9). Radiation therapy may offer improved local control, but the true benefit for retroperitoneal liposarcoma remains controversial (10). Sarcoma MDT Series

促结缔组织增生性小圆细胞肿瘤(desmoplastic small round cell tumor,DSRCT)是一种好发于青少年腹腔、盆腔内的高度恶性肿瘤.由Gerald和Rosai 于1989年首次描述[1],并于1991年正式命名.DSRCT非常少见,在软组织肉瘤中所占比例＜1％.现报道3例发生于腹腔的DSRCT,总结分析其临床病理特征,以提高对该肿瘤的认识、诊断及鉴别诊断水平.