Synchronous retroperitoneal liposarcoma and gastric adenocarcinoma: A rare case report.

Multiple primary malignancies can occur as either synchronous or metachronous tumors, particularly in adults. Retroperitoneal liposarcoma is a rare malignancy arising from adipose tissue, while gastric adenocarcinoma is one of the most common neoplasms worldwide. The simultaneous occurrence of these 2 malignancies is extremely rare, with only 1 case reported worldwide. Here, we present the case of a 52-year-old man diagnosed with both retroperitoneal liposarcoma and gastric adenocarcinoma, marking the second reported case in the world.

Advancing treatment efficacy: combined therapy of eribulin, anlotinib, and camrelizumab in advanced or metastatic retroperitoneal liposarcoma.

Background: Retroperitoneal liposarcoma (RLPS) typically shows limited response to standard chemotherapy, presenting a challenge in treating advanced or metastatic RLPS. Objective: This study aimed to evaluate the potential advantages of a combined therapeutic strategy utilizing eribulin, anlotinib, and camrelizumab. Design: Between December 2020 and March 2023, this retrospective study enrolled patients with advanced or metastatic RLPS who received treatment at Peking University Cancer Hospital Sarcoma Center. The treatment regimen involved eribulin plus anlotinib and camrelizumab administered every 3 weeks (Q3W). Methods: Efficacy was assessed following the Response Evaluation Criteria in Solid Tumors version 1.1, while safety was evaluated using the Common Terminology Criteria for Adverse Events version 5.0. Results: The study included 47 patients with RLPS with a median age of 55.5 years. Patients received a median of 4.5 (range, 2-21) cycles of treatment. Notably, partial response was observed in 8 patients (18.2%), while 25 (56.8%) exhibited stable disease. The objective response rate (ORR) and disease control rate were 18.2% and 75%, respectively. Significant differences in ORR were observed among histological subtypes (well-differentiated vs de-differentiated vs myxoid: 0 vs 17.9% vs 50%; p = 0.039). Six patients underwent surgery before disease progression, and one patient with myxoid liposarcoma (MLPS) had a pathological complete response. With a median follow-up of 21.8 (range, 2.7-30.7) months, the median progression-free survival (mPFS) was 6.9 (95% confidence interval (CI), 4.7-9.1) months, and the 6-month PFS rate was 60.5%. Based on various histological subtypes, the mPFS was 8.4 (95% CI, 4.1-12.7) months with well-differentiated liposarcoma, 5.8 (95% CI, 3.3-8.3) months with de-differentiated liposarcoma and not reached with MLPS, respectively. Treatment-related adverse events (TRAEs) of any grade occurred in 36 (76.6%) patients, with grade 3 or higher TRAEs in 21 (44.7%) patients. The most common TRAEs were neutropenia (53.2%), proteinuria (21.3%), and anorexia (21.3%). Conclusion: The combined treatment strategy involving eribulin, anlotinib, and camrelizumab showed promising efficacy and manageable safety in patients with advanced or metastatic RLPS, particularly in those with MLPS.

Giant retroperitoneal liposarcoma with multiple organ involvement: a case report and literature review.

BACKGROUND: Retroperitoneal liposarcoma (RPLPS) is a relatively rare disease. Liposarcomas vary in size, but sizeable RPLPS larger than 30 cm in diameter are very rare, and their diagnosis and treatment present significant challenges. CASE PRESENTATION: We report a 58-year-old male patient who was admitted to the hospital with an increased abdominal circumference and was later diagnosed with a giant RPLPS. The liposarcoma was found to adhere to the right kidney and the entire ureter, invading the ascending colon. The patient underwent complete combined surgical resection. The tumor was removed intact, measured 55.0 cm × 30.0 cm × 18.0 cm, and weighed 19.8 kg. Histopathologic analysis revealed well-differentiated liposarcoma (WDLPS). The patient was successfully discharged from the hospital and followed up for 6 months with no signs of recurrence. CONCLUSION: RPLPS is a rare tumor with atypical clinical presentation. Surgery remains the most effective method of treatment for retroperitoneal sarcomas, with complete removal if there is local invasion. Preoperative examination, including three-dimensional (3D) reconstruction, is essential for surgical success. The role of adjuvant radiotherapy or chemotherapy remains controversial. However, clinicians should not rule them out as viable options.

Prognostic Nutritional Index (PNI): A More Promising Nutritional Predictor for Patients Undergoing Surgery for Retroperitoneal Liposarcoma.

Background: Extended surgery with multi-visceral resection is the standard treatment for retroperitoneal liposarcoma (RLPS). Malnutrition tends to result in increased surgical complications and reduced survival. The aim of this study was to identify the prognostic role of nutritional status in patients with RLPS. Patients and methods: Data from 189 consecutive patients with RLPS who underwent surgical treatment at the Peking University Cancer Hospital Sarcoma Center between April 2011 and August 2022 were retrospectively reviewed. The following nutritional parameters were calculated: nutritional risk index, prognostic nutritional index (PNI) and Nutrition Risk Screening 2002. Time-dependent receiver operating characteristic (time-ROC) curve analysis was conducted to compare the prognostic utility of nutritional indicators. The associations between nutritional indicators and major complications, local recurrence-free survival (LRFS) and overall survival (OS) were investigated. Results: Based on the time-ROC curve analysis, the PNI was superior to other nutritional indices at predicting OS. The optimal cut-off value of PNI was 41.2. The PNI was significantly inversely associated with tumor size, tumor grade, and histological subtype. Patients in the low PNI group (< 41.2) had significantly shorter LRFS and OS than those in the high PNI (≥ 41.2) group, with higher major morbidity and mortality rates. The PNI was found to be a unique nutritional predictor that independently predicted LRFS and OS in the multivariate analysis. Conclusion: The PNI is an effective tool for nutritional assessment in patients with RLPS. A low PNI value in patients with RLPS predicts worse survival outcomes.

Surgical outcomes of major vascular resection for retroperitoneal liposarcoma from a high­volume sarcoma center: a propensity score matching analysis.

PURPOSE: Radical resection of retroperitoneal liposarcoma (RLPS) may necessitate vascular resection and reconstruction. The study was conducted to assess surgical outcomes of surgery for RLPS with major vascular involvement. METHODS: Patients with RLPS who underwent surgical resection at the Sarcoma Center of Peking University Cancer Hospital between April 2011 and December 2022 were identified from a prospectively maintained database. Patients were classified into two groups: vascular resection and non-vascular resection groups. A propensity score matching analysis was performed to eliminate baseline differences between the groups. Surgical details and postoperative outcomes were analyzed. Furthermore, prognostic factors for local recurrence-free survival (LRFS) and overall survival (OS) were assessed. RESULTS: Overall, 199 patients were identified and the median follow-up period was 48 (interquartile range [IQR] 45-69) months. Vascular resection was performed in 42 (21%) patients, 25 of whom had vascular infiltration. A total of 39 patients had vascular replacement and 3 patients underwent partial resection (side-wall resection). Vascular resection was burdened by higher rates of major morbidity (38% vs. 14%, p < 0.001) and 30-day mortality (7.1% vs. 1.3%, p = 0.005). After propensity-matched analysis, patients who underwent vascular resection had 5-year LRFS and OS rates comparable to those without vascular involvement. Major vascular resection was not an independent risk factor for LRFS or OS. CONCLUSIONS: Although accompanied by increased risks of major morbidity and mortality, the major vascular resection enabled radical resection in patients with advanced RLPS, affording comparable 5-year LRFS and OS rates compared to those who did not.

Explainable machine learning predicts survival of retroperitoneal liposarcoma: A study based on the SEER database and external validation in China.

OBJECTIVE: We have developed explainable machine learning models to predict the overall survival (OS) of retroperitoneal liposarcoma (RLPS) patients. This approach aims to enhance the explainability and transparency of our modeling results. METHODS: We collected clinicopathological information of RLPS patients from The Surveillance, Epidemiology, and End Results (SEER) database and allocated them into training and validation sets with a 7:3 ratio. Simultaneously, we obtained an external validation cohort from The First Affiliated Hospital of Naval Medical University (Shanghai, China). We performed LASSO regression and multivariate Cox proportional hazards analysis to identify relevant risk factors, which were then combined to develop six machine learning (ML) models: Cox proportional hazards model (Coxph), random survival forest (RSF), ranger, gradient boosting with component-wise linear models (GBM), decision trees, and boosting trees. The predictive performance of these ML models was evaluated using the concordance index (C-index), the integrated cumulative/dynamic area under the curve (AUC), and the integrated Brier score, as well as the Cox-Snell residual plot. We also used time-dependent variable importance, analysis of partial dependence survival plots, and the generation of aggregated survival SHapley Additive exPlanations (SurvSHAP) plots to provide a global explanation of the optimal model. Additionally, SurvSHAP (t) and survival local interpretable model-agnostic explanations (SurvLIME) plots were used to provide a local explanation of the optimal model. RESULTS: The final ML models are consisted of six factors: patient's age, gender, marital status, surgical history, as well as tumor's histopathological classification, histological grade, and SEER stage. Our prognostic model exhibits significant discriminative ability, particularly with the ranger model performing optimally. In the training set, validation set, and external validation set, the AUC for 1, 3, and 5 year OS are all above 0.83, and the integrated Brier scores are consistently below 0.15. The explainability analysis of the ranger model also indicates that histological grade, histopathological classification, and age are the most influential factors in predicting OS. CONCLUSIONS: The ranger ML prognostic model exhibits optimal performance and can be utilized to predict the OS of RLPS patients, offering valuable and crucial references for clinical physicians to make informed decisions in advance.

Recurrent retroperitoneal liposarcoma with multiple surgeries: a case report.

Retroperitoneal liposarcoma (RPLPS) is a rare malignant tumor that is typically treated with surgical resection. However, RPLPS often has a high rate of local recurrence, making it crucial to explore new treatment options. In this report, we present the case of a middle-aged woman who experienced seven recurrences and underwent seven surgeries following the initial resection. Currently, the patient's condition remains stable after the eighth surgery. Although there have been numerous reports of RPLPS cases both domestically and internationally, instances of repeated recurrence like this are exceptionally rare. Therefore, we have gathered the patient's case data and conducted a retrospective analysis, incorporating relevant literature, to enhance the understanding of this disease among clinical practitioners.

A rare presentation of retroperitoneal liposarcoma presented with jejunal intussusception: An interesting radiological findings.

A jejunal intussusception as a presentation of retroperitoneal liposarcoma (RLPS) is a rare occurrence. The majority of RLPS are presented as an abdominal mass, however, having a jejunal obstruction is an interesting case. The aim is to describe the management of jejunal intussusception secondary to atypical lipomatous tumours with concurrent RLPS. A 61-year-old lady presented with a sudden onset of intestinal obstruction with 1 month of constitutional symptoms and an enlarging right lumbar mass. Computed tomography showed a small bowel intussusception with diffuse peritoneal and retroperitoneal lipomatosis. Emergency exploratory laparotomy, segmental bowel resection, and partial excision of intraperitoneal mesenteric lipoma were performed. A stage En-bloc resection of the RLPS and right nephrectomy was done later. However, she refused for subsequent surgery. A complete resection is the gold standard in managing RLPS. In this report, the management is rendered not to the standard as the patient first presented with intestinal obstruction requiring emergency reduction with a piecemeal resection. A stage surgery was required to determine a promising prognosis, but the patient refused such surgery. A small bowel intussusception in adults is rare but is mostly caused by a tumor or neoplasm. Early recognition of the complexity of the case should be preempted and referred to the tertiary team for further definitive surgery. Patient exhaustion from the subsequent surgery might hamper the only management available for the case.

Identification of NINJ1 as a novel prognostic predictor for retroperitoneal liposarcoma.

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.

Short- and long-term post-nephrectomy outcomes for retroperitoneal liposarcoma from a high-volume sarcoma center: a propensity score matching analysis.

BACKGROUND: Multivisceral en bloc resection with the ipsilateral kidney is commonly performed in patients with retroperitoneal liposarcoma (RLPS). We evaluated the effect of nephrectomy on short- and long-term outcomes in patients with RLPS. METHODS: Data from a prospectively maintained database of the Peking University Cancer Hospital Sarcoma Center between April 2011 and August 2022 were analyzed. We classified the RLPS patients who underwent surgery into nephrectomy group (NP) and non-nephrectomy group (non-NP). Patients were matched using a 1:1 propensity score to eliminate baseline differences between groups. Postoperative renal function outcomes, major morbidity, and mortality were analyzed to compare short-term outcomes after nephrectomy. Differences in local recurrence-free survival (LRFS) and overall survival (OS) were compared by Kaplan-Meier analysis with respect to oncological benefits. RESULTS: In the matched cohort, patients in the NP group had significantly higher postoperative eGFR and CKD stages, but none required dialysis. Patients between NP and non-NP had a comparable major morbidity (p = 0.820) and 60-day mortality (p = 0.475). Patients in the NP group had a higher 5-year LRFS rates than those in the non-NP group (34.5 vs. 17.8%, p = 0.015), and similar 5-year OS rates (52.4 vs. 47.1%, p = 0.401). Nephrectomy was an independent risk factor for LRFS, but not for major morbidity or OS. CONCLUSIONS: RLPS resection with nephrectomy is related to a mild progression of renal impairment; however, dialysis is rare. En bloc nephrectomy for complete resection of RLPS is safe and improves local control.

Giant retroperitoneal myolipoma mimicking liposarcoma: report of a resected case and review of the literature.

Myolipomas are rare tumors that are often difficult to differentiate from liposarcoma. Herein, we report a case of resected giant myolipoma preoperatively diagnosed as liposarcoma. A 63-year-old woman was suspected of having a large retroperitoneal liposarcoma on October 202X. The patient was referred to our department for tumor resection and a histological diagnosis. After consultation with the urology, obstetric and gynecology, and vascular surgery departments, tumor resection was planned, including the potential resection of other organs. Intraoperative findings revealed a large, elastic, soft tumor with a smooth surface and a capsule occupying the entire abdominal cavity. The tumor was adherent to the stomach, left colon, and uterine adnexa, and no invasion was observed. The tumor was completely resected, and organ resection was not necessary. The tumor was 40 cm in diameter and 4.0 kg in weight. Pathological examination and immunostaining confirmed a diagnosis of myolipoma. The patient's postoperative course was uneventful, and she was discharged on postoperative day 10 with no complications. Twelve months after surgery, the patient was doing well. To the best of our knowledge, we report a complete resection of the largest retroperitoneal myolipoma reported to date. Physicians should consider surgery, even for suspected large sarcomas that may be difficult to resect completely.

Identification of predictors for short-term recurrence: comprehensive analysis of 296 retroperitoneal liposarcoma cases.

BACKGROUND: The short-term (≤ 1 year) recurrence (STR) is the primary determinant impacting both the life quality and survival duration in patients who have undergone surgical resection for retroperitoneal liposarcoma (RPLS), a condition with intricate and ambiguous pathogenesis. The purpose of this study was to analyze the risk factors associated with STR in cases of RPLS and primary retroperitoneal liposarcoma (PRPLS). METHODS: For this retrospective observational study, a total of 296 RPLS cases were selected as research subjects, who experienced tumor recurrence during the follow-up period. The Local recurrence-free survival (LRFS) rates were estimated using the Kaplan-Meier method and subsequently compared between groups utilizing the log-rank test. The subsequent analyses involved univariate and multivariate logistic regression to identify predictors of STR in RPLS cases. Additionally, a logistic regression model was constructed for PRPLS. RESULTS: The 1-, 3-, and 5-year LRFS rates of the 296 RPLS cases were 51.7%, 16.9%, and 7.1%, respectively. In the univariate analysis, several factors were found to be associated with STR, including preoperative neutrophil/lymphocyte ratio (NLR), smoking history, surgical frequency, combined organ excision, operative time, intraoperative bleeding, transfer to the intensive care unit (ICU), multiple primary tumors, tumor shape and capsule characteristics, histological subtype, and presence of tumor necrosis. The elevated preoperative NLR, surgical frequency of ≥ 3 times, transfer to the ICU, presence of multiple primary tumors, and tumor necrosis were identified as independent risk factors for STR in surgically resected RPLS. Conversely, diabetes, intact tumor capsule, and well-differentiated histological subtype appeared to be independent protective factors. Analysis for PRPLS revealed that tumor capsule and tumor necrosis were independent predictors of STR. CONCLUSIONS: The elevated preoperative NLR, surgical frequency of ≥ 3 times, transfer to the ICU, presence of multiple primary tumors, tumor necrosis, and tumor capsule were expected to serve as predictive factors of STR for surgical resected RPLS and PRPLS.

Retroperitoneal dedifferentiated liposarcoma with rare heterologous low-grade osteosarcoma: A case report.

Dedifferentiated liposarcoma is a high-grade entity developed from a preexisting or recurrent well-differentiated liposarcoma, and rarely, it may contain divergent differentiation. We presented the case of a 39-year-old woman with retroperitoneal dedifferentiated liposarcoma with heterologous low-grade osteosarcoma, possessing a special pattern of tumoral calcification.

Immune characteristics of dedifferentiated retroperitoneal liposarcomas and the reliability of regional samples in evaluating their tumor immune microenvironments.

BACKGROUND: Tumor immunotherapy is a new treatment breakthrough for retroperitoneal liposarcoma (RPLS), which is highly invasive and has few effective treatment options other than tumor resection. However, the heterogeneity of the tumor immune microenvironment (TIME) leads to missed clinical diagnosis and inappropriate treatment. Therefore, it is crucial to evaluate whether the TIME of a certain part of the tumor reliably represents the whole tumor, particularly for very large tumors, such as RPLS. METHODS: We conducted a prospective study to evaluate the TIME in different regions of dedifferentiated RPLS (DDRPLS) by detecting the expressions of markers such as CD4+, CD8+, Foxp3+, CD20+, CD68+, LAMP3+, PD-1+ tumor-infiltrating lymphocytes (TILs), and PD-L1 in tumors and corresponding paratumor tissues via immunohistochemistry and RNA sequencing. RESULTS: In DDRPLS, very few TILs were observed. Differentially expressed genes were significantly enriched in cell part and cell functions, as well as the metabolic pathway and PI3K-Akt signaling pathway. In addition, for most tumors (70-80%), the TIME was similar in different tumor regions. CONCLUSIONS: For most tumors (70-80%), the TIME in any region of the tumor reliably represents the whole tumor. DDRPLS may regulate cell functions by modulating the metabolic and PI3K-Akt signaling pathways to promote its malignant behavior.

Retroperitoneal liposarcoma: Case of a giant tumour inside the abdomen.

Retroperitoneal liposarcomas are rare malignant tumours that often grow rapidly in size and become symptomatic lat e in t he disease course, posing diagnostic a nd therapeutic challenges. Although abdominal imaging can rel iab ly diagnose the tumour, definitive diagnosis is only p ossib le th rough bio psy af ter surgical excision , w hich remains the primary treatment modality for these tumours. Long- term sur v ival is p rimarily determ ined throu gh histologic grade and post-resection tumour margins. We report t he case of a 43-year-o ld male patient, see n at Dr Ruth KM Pfau Hospital Karachi, who under went successful surgical excision for a well-differentiated retroperitoneal liposarcoma an d had no rad io gr aphic evidence o f local recurrence at both 3 and 12-month follow-ups.

Gender Differences in Prognosis After Primary Resection for Retroperitoneal Liposarcoma.

BACKGROUND: Current evidence regarding gender difference in retroperitoneal liposarcoma (RLPS) is scarce, so we sought to investigate whether gender may affect prognosis after primary resection of RLPS. METHODS: We used the Surveillance, Epidemiology, and End Results (SEER) database to identify RLPS patients from January 1973 to December 2015. Multivariate cox proportional hazard analysis was adopted to generate adjusted hazard ratio (AHR) and 95% confidence intervals (CIs) of survival outcomes. RESULTS: In total, 2108 RLPS patients, including 971 women and 1137 men, were identified, with a median follow-up of 45.0 (17.0-92.0) months. The 5-year and 10-year overall survival rates were 50.5% and 31.5% for men and 60.4% and 42.5% for women. The 5-year and 10-year disease-specific survival rates for men and women were 71.5%, 57.3% and 76.3%, 62.1%, respectively. We found men were associated with an increased risk of all-cause mortality (AHR 1.3, 95% CI 1.0-1.6, P = .017) but not disease-specific mortality (AHR 1.2, 95% CI .9-1.6, P = .246). The subgroup analyses revealed that men were associated with an increased risk of all-cause mortality in patients with low-grade tumors (AHR 1.8, 95% CI 1.3-2.5) or patients who received non-radical resection (AHR 1.6, 95% CI 1.2-2.1). In the subgroup of low-grade tumors, men were also associated with an increased risk of disease-specific mortality (AHR 2.0, 95% CI 1.2-3.3). CONCLUSION: Men may have worse survival after primary resection of RLPS compared with women, especially in patients with low-grade tumors or patients who received non-radical resection. Gender-based disparities may deserve more attention in patients with RLPS.

Preoperative assessment of retroperitoneal Liposarcoma using volume-based 18F-FDG PET/CT: implications for surgical strategy and prognosis.

PURPOSE: Retroperitoneal liposarcoma (RLPS) poses a challenging scenario for surgeons due to its unpredictable biological behavior. Surgery remains the primary curative option for RLPS; however, the need for additional information to guide surgical strategies persists. Volume-based 18F-FDG PET/CT may solve this issue. METHODS: We analyzed data from 89 RLPS patients, measuring metabolic tumor volume (MTV), total lesion glycolysis (TLG), and maximum standardized uptake value (SUVmax) and explored their associations with clinical, prognostic, and pathological factors. RESULTS: MTV, TLG of multifocal and recurrent RLPS were significantly higher than unifocal and primary ones (P < 0.001, P < 0.001, P = 0.003 and P = 0.002, respectively). SUVmax correlated with FNCLCC histological grade, mitotic count and Ki-67 index (P for G1/G2 = 0.005, P for G2/G3 = 0.017, and P for G1/G3 = 0.001, P < 0.001 and P = 0.024, respectively). MTG, TLG and SUVmax of WDLPS were significantly lower than DDLPS and PLPS (P for MTV were 0.009 and 0.022, P for TLG were 0.028 and 0.048, and P for SUVmax were 0.027 and < 0.001, respectively). Multivariable Cox analysis showed that MTV > 457.65 (P = 0.025), pathological subtype (P = 0.049) and FNCLCC histological grade (P = 0.033) were related to overall survival (OS). CONCLUSIONS: Our findings indicate that MTV is an independent prognostic factor for RLPS, while MTV, TLG, and SUVmax can preoperatively predict multifocal lesions, histological grade, and pathological subtype. Volume-based 18F-FDG PET/CT offers valuable information to aid in the decision-making process for RLPS surgical strategies.

Predictors and outcomes of recurrent retroperitoneal liposarcoma: new insights into its recurrence patterns.

BACKGROUND: The clinical profiles of recurrent retroperitoneal liposarcoma (RLS) need to be explored. The recurrence patterns of RLS are controversial and ambiguous. METHODS: A total of 138 patients with recurrent RLS were finally recruited in the study. The analysis of overall survival (OS) and recurrence-free survival (RFS) was performed by Kaplan‒Meier analysis. To identify independent prognostic factors, all significant variables on univariate Cox regression analysis (P ≤ 0.05) were subjected to multivariate Cox regression analysis. The corresponding nomogram model was further built to predict the survival status of patients. RESULTS: Among patients, the 1-, 3-, and 5-year OS rates were 70.7%, 35.9% and 30.9%, respectively. The 1-, 3- and 5-year RFS rates of the 55 patients who underwent R0 resection were 76.1%, 50.8% and 34.4%, respectively. The multivariate analysis revealed that resection method, tumor size, status of pathological differentiation, pathological subtypes and recurrence pattern were independent risk factors for OS or RFS. Patients with distant recurrence (DR) pattern usually had multifocal tumors (90.5% vs. 74.7%, P < 0.05); they were prone to experience changes of pathological differentiation (69.9% vs. 33.3%, P < 0.05) and had a better prognosis than those with local recurrence (LR) pattern. R0 resection and combined organ resection favored the survival of patients with DR pattern in some cases. CONCLUSIONS: Patients with DR pattern had better prognosis, and they may benefit more from aggressive combined resection than those with LR pattern. Classifying the recurrence patterns of RLS provides guidance for individualized clinical management of recurrent RLS.

A Large Retroperitoneal Liposarcoma Mimicking an Angiomyolipoma on Pre-operative Imaging: A Case Report.

Retroperitoneal masses present a diagnostic challenge due to their elusive origin and varied clinical manifestations. Among these masses, retroperitoneal liposarcomas, rare tumors of mesenchymal origin, often grow asymptomatically until compressing surrounding structures, necessitating accurate and early diagnosis. Renal angiomyolipomas (AMLs) have also been reported to mimic retroperitoneal liposarcomas on radiographic imaging, further complicating diagnostic processes. The presented case report describes a rare instance of a large well-differentiated liposarcoma that mimicked a renal angiomyolipoma on imaging in a 58-year-old male patient. The patient initially presented with worsening abdominal distension, early satiety, and left-sided flank pain for the past year. Radiographic imaging revealed a large mixed echogenic lesion measuring 22 x 13 cm in the left kidney with diffuse fat contribution, suspected to be a giant renal angiomyolipoma. The patient underwent selective arterial embolization by interventional radiology. Follow-up imaging eight months later showed an increase in the size of the mass, raising suspicion of a liposarcoma. Surgical resection of the mass and a radical left nephrectomy were performed, with final pathology confirming the diagnosis of a well-differentiated liposarcoma. This case highlights the importance of accurate diagnosis and the potential for liposarcomas to mimic other masses on imaging, despite their rarity.

Surgical approach for complete resection of giant retroperitoneal liposarcoma with diaphragmatic hernia via ninth rib thoracotomy.

Background: Resection of a giant retroperitoneal liposarcoma is difficult and technically demanding, especially for large retroperitoneal tumors accompanied by a diaphragmatic hernia. Technically, the open abdominal approach can be time-consuming and difficult to perform, with possible intraoperative complications and other factors bringing psychological and physical difficulties to the patient. This study reports a safe and feasible approach for the complete resection of a large retroperitoneal tumor complicated by a diaphragmatic hernia. Methods: A 58-year-old male patient with persistent upper abdominal pain and distension was treated at a local hospital on 4 July 2022. Computed tomography showed a mixed-density mass on the right retroperitoneum, and liposarcoma was considered. On 6 July 2022, the patient was transferred to our hospital for further treatment. Computed tomography showed a mass with low-density fatty shadow in the right adrenal region. The boundary with the right adrenal gland was unclear. The mass was 102 mm × 74 mm, and the right lobe of the liver was compressed. Insufficiency of the right middle lobe of the liver was seen due to a right diaphragmatic hernia and left mediastinal deviation. We considered the traditional approach for tumor resection via laparotomy, but we opted to perform a comprehensive evaluation first. The tumor was close to the back of the right kidney and liver, causing the diaphragm to rise because of its proximity to these organs. Exposing the tumor through laparotomy would be difficult, making it challenging to remove. The patient had a diaphragmatic hernia and moderate pulmonary dysfunction; therefore, we decided to enter the abdomen through a thoracotomy of the ninth rib. Results: Using our technique, the tumor was easily visualized and completely removed in approximately 30 min. The intraoperative blood loss was 100 ml, and no postoperative bleeding, pneumothorax, intestinal fistula, infection, or other complications occurred. Conclusion: The transthoracic approach may be a safer and more feasible resection method than the traditional open approach for patients with giant retroperitoneal liposarcoma with a diaphragmatic hernia.