Imaging in retroperitoneal soft tissue sarcoma

ASO Practice Guidelines Series: Multidisciplinary Management of Retroperitoneal Sarcomas

Retroperitoneal sarcomas (RPS) represent a rare and biologically diverse group of malignancies, distinct from soft tissue sarcomas arising in other anatomic regions. Their deep-seated location, large size at presentation and proximity to critical structures contribute to diagnostic delays, treatment challenges, and variable oncologic outcomes, particularly when managed outside high-volume referral centers. Current international guidelines emphasize the importance of preoperative biopsy, review by a sarcoma pathologist, management in a referral center, multidisciplinary case discussion, consideration for clinical trials enrollment, and prospective database inclusion as standards of care. Given that the quality of the initial surgical resection-achieving complete macroscopic resection with margins tailored to the histologic type-remains the most important modifiable prognostic factor, adherence to international best practices in surgical and multimodal treatment is crucial to optimize patient outcomes. This article reviews contemporary management strategies for adult-type RPS, emphasizing the importance of multidisciplinary expertise.

Retroduodenal lymphangiomyoma: A rare cause of abdominal pain - A case report

BACKGROUND

Lymphangiomyomas are rare benign tumors arising from the lymphatic system, most commonly found in the retroperitoneum. Retroduodenal lymphangiomyomas are exceedingly rare and present significant diagnostic challenges due to their nonspecific symptoms and overlapping features with other retroperitoneal and gastrointestinal pathologies.

CASE PRESENTATION

We report a 48-year-old man with persistent abdominal pain lasting several weeks. Clinical examination and laboratory investigations were unremarkable. Gastroscopy revealed no abnormalities. Contrast-enhanced computed tomography (CT) identified a well-demarcated, non-enhancing retroduodenal soft tissue lesion measuring 36 mm × 30 mm with punctate calcifications, suggestive of a benign process. Endosonography confirmed the lesion's location between the aorta and inferior vena cava. A fine-needle biopsy was avoided due to the lesion's vascular nature. Surgical excision was performed, and histopathological analysis revealed anastomosing vascular channels with smooth muscle proliferation, confirming the diagnosis of lymphangiomyoma. Postoperative recovery was uneventful, and follow-up imaging showed no recurrence.

DISCUSSION

This case underscores the importance of a multidisciplinary approach involving radiology, surgery, and pathology in the diagnosis and management of retroduodenal lymphangiomyomas. Contrast-enhanced CT and histopathology are critical in distinguishing lymphangiomyomas from other retroperitoneal masses. Complete surgical excision remains the definitive treatment to prevent recurrence.

CONCLUSION

Although rare, retroduodenal lymphangiomyomas should be considered in the differential diagnosis of retroperitoneal masses with nonspecific symptoms.

Recurrent High-Grade Retroperitoneal Sarcoma: A Case Report

Retroperitoneal sarcomas are rare and challenging soft tissue tumors that can have an insidious presentation. These tumors may present asymptomatically or display vague symptoms such as nausea, abdominal pain, and constipation. Rapid detection and treatment of these tumors are necessary as they may metastasize or compress adjacent structures within the body. Imaging and biopsy play a critical role in diagnosing and managing retroperitoneal sarcomas, with treatment decisions largely influenced by the tumor's histological subtype. Due to the high recurrence rate of these tumors, adjuvant therapies and consistent monitoring are essential. This case report discusses the recurrence of a high-grade liposarcoma in a 73-year-old male patient status post retroperitoneal sarcoma resection. Despite initial successful surgical intervention, the patient's non-compliance with follow-up care led to a recurrence, highlighting the importance of long-term monitoring, adherence to post-surgical protocols, and multidisciplinary decision-making.

UK guidelines for the management of soft tissue sarcomas

Soft tissue sarcomas (STS) are rare tumours arising in mesenchymal tissues and can occur almost anywhere in the body. Their rarity, and the heterogeneity of subtype and location, means that developing evidence-based guidelines is complicated by the limitations of the data available. This makes it more important that STS are managed by expert multidisciplinary teams, to ensure consistent and optimal treatment, recruitment to clinical trials, and the ongoing accumulation of further data and knowledge. The development of appropriate guidance, by an experienced panel referring to the evidence available, is therefore a useful foundation on which to build progress in the field. These guidelines are an update of the previous versions published in 2010 and 2016 [1, 2]. The original guidelines were drawn up by a panel of UK sarcoma specialists convened under the auspices of the British Sarcoma Group (BSG) and were intended to provide a framework for the multidisciplinary care of patients with soft tissue sarcomas. This iteration of the guidance, as well as updating the general multidisciplinary management of soft tissue sarcoma, includes specific sections relating to the management of sarcomas at defined anatomical sites: gynaecological sarcomas, retroperitoneal sarcomas, breast sarcomas, and skin sarcomas. These are generally managed collaboratively by site specific multidisciplinary teams linked to the regional sarcoma specialist team, as stipulated in the recently published sarcoma service specification [3]. In the UK, any patient with a suspected soft tissue sarcoma should be referred to a specialist regional soft tissues sarcoma service, to be managed by a specialist sarcoma multidisciplinary team. Once the diagnosis has been confirmed using appropriate imaging and a tissue biopsy, the main modality of management is usually surgical excision performed by a specialist surgeon, combined with pre- or post-operative radiotherapy for tumours at higher risk for local recurrence. Systemic anti-cancer therapy (SACT) may be utilised in cases where the histological subtype is considered more sensitive to systemic treatment. Regular follow-up is recommended to assess local control, development of metastatic disease, and any late effects of treatment.

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.

A Case of a Giant Liposarcoma at Binh Dan Hospital

Retroperitoneal liposarcomas (RLSs) are uncommon mesenchymal tumors that might present a diagnostic challenge due to their rarity and anatomical location. Despite grossly complete resections, they are commonly linked to a high recurrence rate, necessitating long-term or indefinite follow-up. This report discusses a 59-year-old male patient referred to the Gastrointestinal Department due to chronic abdominal distention, right-sided back pain, and a sizable abdominal mass. The diagnosis was an RLS, and the patient underwent en bloc resection of the mass.

Overview of F18-FDG uptake patterns in retroperitoneal pathologies: imaging findings, pitfalls, and artifacts

INTRODUCTION

Retroperitoneum can be the origin of a wide variety of pathologic conditions and potential space for disease spread to other compartments of the abdomen and pelvis. Computed tomography (CT) and magnetic resonance imaging (MRI) are often the initial imaging modalities to evaluate the retroperitoneal pathologies, however given the intrinsic limitations, F18-FDG PET/CT provides additional valuable metabolic information which can change the patient management and clinical outcomes. We highlight the features of retroperitoneal pathologies on F18-FDG PET/CT and the commonly encountered imaging artifacts and pitfalls. The aim of this review is to characterize primary and secondary retroperitoneal pathologies based on their metabolic features, and correlate PET findings with anatomic imaging.

CONCLUSION

Retroperitoneal pathologies can be complex, ranging from oncologic to a spectrum of non-oncologic disorders. While crosse-sectional imaging (CT and MRI) are often the initial imaging modalities to localize and characterize pathologies, metabolic information provided by F18-FDG PET/CT can change the management and clinical outcome in many cases.

Survival nomograms for patients with retroperitoneal soft tissue sarcoma based on the SEER database and an external cohort

BACKGROUND

Retroperitoneal soft tissue sarcoma (RPS) is a quite rare disease,and new nomograms need to be constructed to predict the overall survival (OS) and cancer specific survival (CSS) of RPS patients.

METHODS

The clinical data of patients with RPS were extracted from the Surveillance, Epidemiology, and End Results (SEER) database and authors' hospital. The LASSO method and COX proportional hazard regression were used to screen independent risk factors which were used to develop nomograms. Nomograms was evaluated in terms of discrimination by consistency index (C-index) and calibration curve. Decision curve analysis (DCA) and integrated discrimination index (IDI) were performed to assess net benefit and the improvement of model, respectively. Kaplan-Meier method and log-rank test were applied to compare the survival difference between groups.

RESULTS

A total of 1164 cases were enrolled which were divided into training cohort (n = 814) and internal validation cohort (n = 350) at a 7:3 ratio. The discrimination of nomograms were good with C-index of 0.728 (95%CI = 0.704-0.752, R2 = 0.270), 0.754 (95%CI = 0.729-0.779, R2 = 0.281) for OS and CSS, respectively. Calibration curve showed good predictive accuracy of nomograms both in internal and external validation cohort, and IDI indicated that nomograms perform well than AJCC stage. Kaplan Meier curve and log-rank test uncovered statistically significance survival difference between high- and low-risk groups with P < 0.001 in terms of OS and CSS.

CONCLUSION

Novel nomograms predicting the OS and CSS of RPS patients perform well in discrimination, calibration, clinical benefit and IDI. These nomograms may facilitate risk stratification and making clinical decision.

A CT-based radiomics classification model for the prediction of histological type and tumour grade in retroperitoneal sarcoma (RADSARC-R): a retrospective multicohort analysis

BACKGROUND

Retroperitoneal sarcomas are tumours with a poor prognosis. Upfront characterisation of the tumour is difficult, and under-grading is common. Radiomics has the potential to non-invasively characterise the so-called radiological phenotype of tumours. We aimed to develop and independently validate a CT-based radiomics classification model for the prediction of histological type and grade in retroperitoneal leiomyosarcoma and liposarcoma.

METHODS

A retrospective discovery cohort was collated at our centre (Royal Marsden Hospital, London, UK) and an independent validation cohort comprising patients recruited in the phase 3 STRASS study of neoadjuvant radiotherapy in retroperitoneal sarcoma. Patients aged older than 18 years with confirmed primary leiomyosarcoma or liposarcoma proceeding to surgical resection with available contrast-enhanced CT scans were included. Using the discovery dataset, a CT-based radiomics workflow was developed, including manual delineation, sub-segmentation, feature extraction, and predictive model building. Separate probabilistic classifiers for the prediction of histological type and low versus intermediate or high grade tumour types were built and tested. Independent validation was then performed. The primary objective of the study was to develop radiomic classification models for the prediction of retroperitoneal leiomyosarcoma and liposarcoma type and histological grade.

FINDINGS

170 patients recruited between Oct 30, 2016, and Dec 23, 2020, were eligible in the discovery cohort and 89 patients recruited between Jan 18, 2012, and April 10, 2017, were eligible in the validation cohort. In the discovery cohort, the median age was 63 years (range 27-89), with 83 (49%) female and 87 (51%) male patients. In the validation cohort, median age was 59 years (range 33-77), with 46 (52%) female and 43 (48%) male patients. The highest performing model for the prediction of histological type had an area under the receiver operator curve (AUROC) of 0·928 on validation, based on a feature set of radiomics and approximate radiomic volume fraction. The highest performing model for the prediction of histological grade had an AUROC of 0·882 on validation, based on a radiomics feature set.

INTERPRETATION

Our validated radiomics model can predict the histological type and grade of retroperitoneal sarcomas with excellent performance. This could have important implications for improving diagnosis and risk stratification in retroperitoneal sarcomas.

FUNDING

Wellcome Trust, European Organisation for Research and Treatment of Cancer-Soft Tissue and Bone Sarcoma Group, the National Institutes for Health, and the National Institute for Health and Care Research Biomedical Research Centre at The Royal Marsden NHS Foundation Trust and The Institute of Cancer Research.

Conjugated Nanoparticles for Solid Tumor Theranostics: Unraveling the Interplay of Known and Unknown Factors

Cancer diagnoses have been increasing worldwide, and solid tumors are among the leading contributors to patient mortality, creating an enormous burden on the global healthcare system. Cancer is responsible for around 10.3 million deaths worldwide. Solid tumors are one of the most prevalent cancers observed in recent times. On the other hand, early diagnosis is a significant challenge that could save a person's life. Treatment with existing methods has pitfalls that limit the successful elimination of the disorder. Though nanoparticle-based imaging and therapeutics have shown a significant impact in healthcare, current methodologies for solid tumor treatment are insufficient. There are multiple complications associated with the diagnosis and management of solid tumors as well. Recently, surface-conjugated nanoparticles such as lipid nanoparticles, metallic nanoparticles, and quantum dots have shown positive results in solid tumor diagnostics and therapeutics in preclinical models. Other nanotheranostic material platforms such as plasmonic theranostics, magnetotheranostics, hybrid nanotheranostics, and graphene theranostics have also been explored. These nanoparticle theranostics ensure the appropriate targeting of tumors along with selective delivery of cargos (both imaging and therapeutic probes) without affecting the surrounding healthy tissues. Though they have multiple applications, nanoparticles still possess numerous limitations that need to be addressed in order to be fully utilized in the clinic. In this review, we outline the importance of materials and design strategies used to engineer nanoparticles in the treatment and diagnosis of solid tumors and how effectively each method overcomes the drawbacks of the current techniques. We also highlight the gaps in each material platform and how design considerations can address their limitations in future research directions.

Pelvic soft tissue sarcomas

Pelvic soft tissue sarcomas (PSTS) are a rare, heterogeneous group of tumors. They have been usually analyzed with retroperitoneal sarcomas (RPS), but actually have key differences. Due to their unique anatomic location, symptomatic presentation of PSTS may be more common than RPS. Adequate imaging approach is paramount for guiding differential diagnosis, while preoperative biopsy is mandatory, especially when preoperative treatment may be considered as initial approach. The most frequent histologic subtype is leiomyosarcoma, which is different as expected in the retroperitoneum where liposarcoma is the commonest histology. Also solitary fibrous tumor is commonly diagnosed in the pelvis. Surgical approach for PSTS differs from that for RPS mainly due to anatomic relations. Similarly, in the lack of definite evidence from specific trials about neoadjuvant and adjuvant treatments, the anatomic constraints to obtain wide margins in the pelvis as well as the expected functional outcome in case of organ resections should be factored into decision for individualized treatment offer. Vascular and genitourinary involvement are frequent, as well as herniation through pelvic foramina. For these reasons a multidisciplinary surgical team should always be considered. Early referral of these patients to high-volume centers is critical and may impact on survival, given that optimal initial resection is a major predictor of curative treatment. International consensus on PSTS treatment is advocated, similarly to the recent efforts realized for RPS.

Management of recurrent retroperitoneal sarcomas

Recurrent retroperitoneal sarcomas are rare, with patterns of recurrence determined by the histologic subtype. A range of patient characteristics and treatment profiles combined with a myriad of presentations and clinical courses of recurrences make this diverse entity challenging to manage. Although surgical resection improves survival in select patients, the oncological outcomes are inferior to that of primary retroperitoneal sarcomas. Management options for unresectable disease include local ablative therapy, radiation and systemic therapy, with palliative surgery indicated occasionally. Attempts at disease control must be balanced with potential morbidity and impact on the patient's quality of life. This review aims to offer insights into the current understanding of recurrent retroperitoneal sarcomas and provide some guidance on management.

CT and MR Imaging of Retroperitoneal Sarcomas: A Practical Guide for the Radiologist

Primary retroperitoneal sarcomas (RPS) represent around 10-16% of all sarcomas, with liposarcomas and leiomyosarcomas being the most common subtypes. RPS have some peculiar characteristics, imaging appearances, worse prognosis, and complications compared to other locations of sarcoma. Commonly, RPS primarily present as large masses, progressively encasing adjacent structures, causing mass effect, and complications. RPS diagnosis is often challenging, and these tumors may be overlooked; however, failure to recognize RPS characteristics leads to a worse prognosis for the patients. Surgery is the only recognized curative treatment, but the anatomical constraints of the retroperitoneum limit the ability to achieve wide resection margins; therefore, these tumors have a high rate of recurrence, and require long-term follow-up. The radiologist has an important role in the diagnosis of RPS, the definition of their extent, and their follow-up. Specific knowledge of the main imaging findings is required to reach an early diagnosis, and, ultimately, to guarantee the best patient management. This article provides an overview of the current knowledge regarding cross-sectional imaging features of patients with retroperitoneal sarcomas, presenting tips and tricks to improve imaging diagnosis of RPS.

Management of Recurrent Retroperitoneal Sarcoma

Recurrence after resection of retroperitoneal sarcoma is common and varies by histological subtype. Pattern of recurrence is similarly affected by histology (e.g., well-differentiated liposarcoma is more likely to recur locoregionally, whereas leiomyosarcoma is more likely to develop distant metastases). Radiotherapy may provide effective locoregional control in limited circumstances and the data on the impact of chemotherapy are scant. Surgery for locally recurrent disease is associated with the greatest survival benefit; however, data are retrospective and from a highly selected subgroup of patients. Limited retrospective data have also suggested a survival association with the resection of limited distant metastases. Given the complexity of these patients, multidisciplinary evaluation at a high-volume sarcoma center is critical.

Lipoma and Its Doppelganger: The Atypical Lipomatous Tumor/Well-Differentiated Liposarcoma

Lipomatous tumors are among the most common soft tissue lesions encountered by the general surgeon. Shared history and clinical presentation make differentiation between benign lipomas and low-grade liposarcomas a diagnostic dilemma. This article reviews the epidemiology, clinical history, diagnostic workup, management, natural history, and surveillance of benign lipomas and atypical lipomatous tumors/well-differentiated liposarcomas. Although it is important that aggressive, potentially malignant atypical lipomatous tumors and liposarcomas be managed in a multidisciplinary, preferably high-volume setting, it is equally as important for the nonspecialist general surgeon to be familiar with lipoma and its doppelganger-the well-differentiated liposarcoma.

Reliability and accuracy in radiographic measurements of musculoskeletal tumors

Tumor size and growth are important parameters when evaluating bone and soft tissue neoplasms. There are no reports comparing the intra- and interobserver reliability among physicians in their evaluation of musculoskeletal (MSK) tumor imaging. This study investigates the accuracy and precision of measurements made by orthopedic and radiology physicians in different stages of training. Blinded magnetic resonance imaging (MRI) scans from six patients, three soft tissue, and three bone tumors were selected: each case included an "old" and "new" scan that was performed at least 3 months apart. Fourteen participants were selected, representing varying levels of education and experience, including two of each of the following: medical students, orthopedic and radiology residents, oncology and nononcologic orthopedic attendings, and MSK and non-MSK radiology attendings. Participants compared the old and new studies, recording tumor size in the transverse, cranial-caudal, and anterior-posterior dimensions, and determined if the tumor was stable or unstable. The MRI's official report served as the "gold standard." Average intraobserver variability (|Trial 1 - Trial 2|/[(Trial 1 + Trial 2)/2])) in size measurements was 11.08% (0.00%-68.62%). The lowest variability was recorded by the MSK radiologist 1 (6.16%), and the greatest variability by Orthopedic Surgery Resident 1 (16.70%). Participants correctly determined stability 82% of the time (71%-100%). Only MSK radiologists correctly determined stability in over 90% of cases. There is considerable variability and inaccuracy in MRI-based measurements of MSK tumors. These findings motivate opportunities for improving MSK imaging education of radiology and orthopedic residents. Physicians ordering MRI scans should evaluate them themselves, instead of relying on the radiology report alone, to inform clinical decision-making.

Retroperitoneal and Mesenteric Liposarcomas

Retroperitoneal liposarcomas are a rare entity and are comprised mostly of the well-differentiated and dedifferentiated subtypes. Eight-year survival ranges from 30% to 80% depending on histologic subtype and grade. Surgery is the cornerstone of treatment and compartment resection is the current standard. Mesenteric liposarcomas are extremely rare and comprise more high-grade lesions, with poorer prognosis of 50% 5-year overall survival. They are managed with a similar aggressive surgical approach. This review presents the current management of retroperitoneal and mesenteric liposarcomas.

The Role of Preoperative 18F-fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Retroperitoneal Sarcoma

¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) was used to predict pathologic grades based on the maximum standardized uptake value (SUVmax) in soft tissue sarcoma and bone sarcoma. In retroperitoneal sarcoma (RPS), the effectiveness of PET was not well known. This study was designed to investigate the association of SUVmax with histopathologic grade and evaluate the usefulness of ¹⁸F-FDG PET/CT before operation. Patients at Samsung Medical Center undergoing primary surgery for retroperitoneal sarcoma with preoperative ¹⁸F-FDG PET/CT imaging between January 2001 and February 2020 were investigated. The relationship between SUVmax and histologic features was assessed. The association of SUVmax with overall survival (OS), local recurrence (LR), and distant metastasis (DM) were studied. Of the total 129 patients, the most common histologic subtypes were liposarcoma (LPS; 68.2%) and leiomyosarcoma (LMS; 15.5%). The median SUVmax was 4.5 (range, 1- 29). Moreover, SUVmax was correlated with tumor grade (p < 0.001, Spearman coefficient; 0.627) and mitosis (p < 0.001, Spearman coefficient; 0.564) and showed a higher value in LMS (12.04 ± 6.73) than in dedifferentiated liposarcoma (DDLPS; 6.32 ± 4.97, p = 0.0054). SUVmax was correlated with pathologic parameters (tumor grade and mitosis) in RPS and was higher in the LMS group than the DDLPS group. The optimal SUVmax threshold to distinguish high tumor grade was 4.8. Those with a SUVmax greater than the threshold showed poor prognosis regarding OS, LR, and DM (p < 0.001).

Retroperitoneal Sarcoma Care in 2021

Soft-tissue sarcomas are biologically heterogenous tumors arising from connective tissues with over 100 subtypes. Although sarcomas account for <1% of all adult malignancies, retroperitoneal sarcomas are a distinct subgroup accounting for <10% of all sarcomatous tumors. There have been considerable advancements in the understanding and treatment of retroperitoneal sarcoma in the last decade, with standard treatment consisting of upfront primary surgical resection. The evidence surrounding the addition of radiation therapy remains controversial. There remains no standard with regards to systemic therapy, including immunotherapy. Adjunctive therapy remains largely dictated by expert consensus and preferences at individual centers or participation in clinical trials. In this 2021 review, we detail the anatomical boundaries of the retroperitoneum, clinical characteristics, contemporary standard of care and well as recent advancements in retroperitoneal sarcoma care. Ongoing international collaborations are encouraged to advance our understanding of this complex disease.

Interdisciplinary Surgical Treatments and Long-Term Outcomes of Lumbar Spinal Tumors With Retroperitoneal Involvements: A Retrospective Case Series Study

Purpose

Surgical treatments are technically challenging for lumbar spinal tumor (LST) with extensive retroperitoneal involvements. Our study aimed to report the experience and outcomes concerning interdisciplinary surgical collaborations in managing such LSTs.

Patients and Methods

Nine patients underwent interdisciplinary surgical treatments which were performed by specialists, namely, spinal, vascular, and urinary surgeries. Data on clinical characteristics were collected, and the Visual Analogue Scale (VAS) and the Japanese Orthopaedic Association Score (JOAS) were used in the evaluation before and after surgery. The postoperative complications and the long-term outcomes were reported as well.

Results

The interdisciplinary work included double J catheter indwelling (n = 9), nephrostomy (n = 5), replacement of the common iliac vein (n = 2), abdominal aorta repair (n = 3), and vital vessel repair (n = 8). The early-stage complications included complaints of moderate low back pain and slight implant shift (n = 1, 11.1%) and tardive ureterodialysis (n = 1, 11.1%). The 3- and 5-year disease-free survival rates were 76.2 ± 14.8 and 50.8 ± 23.0%, respectively, during the mean follow-up of 34.6 ± 17.9 months (range, 9.5–68.7). Besides this, more blood loss was associated with recurrent and metastatic tumor status (p = 0.043) and surgery time >5 h (p = 0.023). Remarkable pain relief and favorable quality of life were achieved based on the postoperative VAS (3.3 ± 0.9, p < 0.001) and JOAS (16.6 ± 0.5, p < 0.001).

Conclusions

The treatments of LSTs with wide-range retroperitoneal involvements require interdisciplinary surgical collaborations to lower the risks and improve the long-term outcomes. High-quality prospective cohort studies with large samples are warranted to establish general surgical protocols in managing LSTs with extensive retroperitoneal involvements.

Current update on IVC leiomyosarcoma

Primary leiomyosarcoma of the inferior vena cava (IVC) is a rare soft tissue sarcoma associated with poor prognosis. Patients are often asymptomatic or present with nonspecific abdominal symptoms, which delays initial diagnosis and contributes to poor oncologic outcome. Key imaging modalities include ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI). Characteristic imaging features include imperceptible caval lumen, dilation of the IVC, heterogeneous enhancement of the tumor, and development of extensive collateral circulation. Surgical resection is the mainstay of treatment, while chemotherapy and/or radiation may serve as therapy adjuncts. This article reviews the pathology, clinical findings, imaging features and management of IVC leiomyosarcoma.

Delayed retroperitoneal liposarcoma diagnosis and management in a patient with massive obesity

People suffering from extreme obesity may be exposed to delayed diagnosis and treatment of cancer. A 37-year-old woman (weight = 245 kg, body mass index (BMI) = 79 kg/m²), presented a sepsis associated with nonspecific abdominal pain for 4 months. After several unsuccessful attempts due to her weight and a large waist circumference, abdominal CT scan was finally successfully performed and showed a large retroperitoneal mass. An ultrasound-guided core needle biopsy was performed and was in favor of a liposarcoma. Surgery was performed to remove the entire tumor of an estimated weight of 98 kg, a giant retroperitoneal dedifferentiated liposarcoma. This case highlights the difficulties to screen, diagnose, and manage cancers encountered in patients suffering from massive obesity.

Multidisciplinary Management of Retroperitoneal Sarcoma: Diagnosis, Prognostic Factors and Treatment

Simple Summary

The management of retroperitoneal sarcomas can be challenging due to the variety of their presentation, histopathological types, and behaviours. This literature review provides a comprehensive and practical overview of the management of retroperitoneal sarcomas, focusing on diagnostic challenges, prognostic factors, multidisciplinary aspects of treatment and new research perspectives.

Abstract

Retroperitoneal sarcomas (RPS) are rare cancers whose management can be challenging due to various presentation patterns, multiple organ involvement, and a high local and distant recurrence rate. Histopathology and prognostic factors analysis are essential to predict the behaviour of the disease and plan the best therapeutic strategy. To date, surgery is still the main therapeutic option that guarantees a chance of cure from the primary disease. While chemotherapy and radiotherapy seem to be good options for controlling metastatic and recurrent irresectable disease, their role in the treatment of primary RPS remains unclear. This literature review aims to provide a comprehensive overview of the multidisciplinary aspects of RPS management in high-volume centres, summarising the diagnostic path, the prognostic factors, and the most suitable therapeutic options.

[French ccAFU guidelines - update 2020-2022: retroperitoneal sarcoma]

OBJECTIVE

- To update French urological guidelines on retroperitoneal sarcoma.

MATERIALS AND METHODS

- Comprehensive Medline search between 2018 and 2020 upon diagnosis, treatment and follow-up of retroperitoneal sarcoma. Level of evidence was evaluated.

RESULTS

- Chest, abdomen and pelvis CT is mandatory to evaluate any suspected retroperitoneal sarcoma. MRI sometimes helps surgical planning. Before histological confirmation through biopsy, the patient must be registered in the French sarcoma pathology reference network. The biopsy standard should be an extraperitoneal coaxial percutaneous sampling before any retroperitoneal mass therapeutic decision. Surgery is retroperitoneal sarcoma cornerstone. The main objective is grossly negative margins and can be technically challenging. Multimodal treatment risks and benefits must be discussed in multidisciplinary teams. The relapse rate is related to tumor grade and surgical margins. Reported Negative margins rate thus encourage surgery in high-volume centers.

CONCLUSION

- Retroperitoneal sarcoma prognosis is poor and closely related to the quality of initial management. Centralization through dedicated sarcoma pathology network in a high-volume center is mandatory.

Management of Primary Retroperitoneal Sarcoma (RPS) in the Adult: An Updated Consensus Approach from the Transatlantic Australasian RPS Working Group

BACKGROUND

Retroperitoneal soft tissue sarcomas comprise a heterogeneous group of rare tumors of mesenchymal origin that include several well-defined histologic subtypes. In 2015, the Transatlantic Australasian RPS Working Group (TARPSWG) published consensus recommendations for the best management of primary retroperitoneal sarcoma (RPS). Since then, through international collaboration, new evidence and knowledge have been generated, creating the need for an updated consensus document.

METHODS

The primary aim of this study was to critically evaluate the current evidence and develop an up-to-date consensus document on the approach to these difficult tumors. The resulting document applies to primary RPS that is non-visceral in origin, with exclusion criteria as previously described. The relevant literature was evaluated and an international group of experts consulted to formulate consensus statements regarding the best management of primary RPS. A level of evidence and grade of recommendation were attributed to each new/updated recommendation.

RESULTS

Management of primary RPS was considered from diagnosis to follow-up. This rare and complex malignancy is best managed by an experienced multidisciplinary team in a specialized referral center. The best chance of cure is at the time of primary presentation, and an individualized management plan should be made based on the 29 consensus statements included in this article, which were agreed upon by all of the authors. Whenever possible, patients should be enrolled in prospective trials and studies.

CONCLUSIONS

Ongoing international collaboration is critical to expand upon current knowledge and further improve outcomes of patients with RPS. In addition, prospective data collection and participation in multi-institution trials are strongly encouraged.

Retroperitoneal liposarcoma in a nonagenarian

Retroperitoneal liposarcomas are rare tumors arising from the soft tissue of the retroperitoneum and are of mesenchymal cell origin. They can reach a large size prior to causing symptoms and generally have a poor prognosis. We present the case of a 93-year-old lady presenting with a large retroperitoneal liposarcoma at the site of a previous colonic anastomosis for the adenocarcinoma treatment. It caused minimal symptoms initially, but surgical resection was undertaken when the tumor was found to be growing significantly in size. However, due to the tumor's location and its invasion into surrounding structures, the resection was not feasible and subsequently abandoned. A retroperitoneal liposarcoma arising from the site of a previous colonic resection has not been previously described. A review of the diagnosis and current management of these lesions is also given.

High grade sarcoma presenting as multifocal recurrent seromas after inguinal hernia repair: A case report

In this report, we describe a 54-year-old male with cystic retroperitoneal sarcoma extending through the inguinal canal. Patient initially underwent inguinal hernia repair with mesh placement for suspected cord lipoma, after which he developed recurrent loculated retroperitoneal fluid collections refractory to multiple attempts at drain placement and laparotomy. Twenty-nine months after initial surgery, patient was referred to our institution on suspicion of malignancy. Pathology of resections taken during subsequent laparotomy showed foci of malignant cells interspersed throughout reactive proliferations. Follow-up immunohistochemistry confirmed high-grade sarcoma, likely atypical liposarcoma, but was unable to definitively establish subtype. Despite en bloc resection and gemcitabine/docetaxel chemotherapy, local progression continued, and patient was enrolled in clinical trials of doxorubicin with dual immune checkpoint blockade. This case suggests that sarcoma should be considered as a differential diagnosis of retroperitoneal or inguinal mass unresponsive to treatment; and highlights the difficulty of subtyping and managing cystic retroperitoneal sarcoma.

Recurrent giant retroperitoneal liposarcoma with 10 years follow up. Case report and review of literature

INTRODUCTION

This case is of a patient with a recurrent giant retroperitoneal liposarcoma, followed-up and operated multiple times over 10 years. We report this case because of its rarity and review all previous articles reporting "Giant Retroperitoneal Liposarcoma" in the English literature.

CASE DESCRIPTION

A 70 years old man presented to our clinic for dizziness and fatigue. He was incidentally found to have a large retroperitoneal mass filling all the length of the abdominal cavity and shifting all intraabdominal viscera and kidney to the left side. En bloc excision of a 50 × 30 × 18 cm, 9 kg tumor was performed. Final pathology revealed a well-differentiated liposarcoma. Five years later, the patient was reoperated for recurrence and a well-differentiated liposarcoma was excised in 2 pieces (the biggest measuring 14 × 11 × 7 cm) along with the appendix. Four years later the patient was operated on again for a second recurrence, and again a well-differentiated liposarcoma (16 × 10 × 7 cm) extending into the right inguinal canal was excised. One year thereafter, the patient was diagnosed with a third recurrence (22 × 12 cm).

DISCUSSION

Retroperitoneal Liposarcomas are rare tumors, presenting with different histological differentiation. They are diagnosed using multiple imaging modality, mainly CT scan, and it is confirmed by percutaneous large core needle biopsy. R0 Surgical excision remains the proper treatment for non-metastatic tumors, which may necessicate multiorgan resection. They rarely grow to reach a large size and be labled as "Giant Retroperitoneal Liposarcoma".

Accurate 3-gene-signature for early diagnosis of liposarcoma progression

Background

Well- and dedifferentiated liposarcoma (WD/DDLPS) are rare mesenchymal malignant tumors that account for 20% of all sarcomas in adults. The WD form is a low-grade malignancy with a favourable prognosis which may progress to DDLPS, a high-grade aggressive counterpart. WDLPS is referred to as atypical lipomatous tumour (ALT) when localised in extremities, due to its better prognosis. Currently the final differential diagnosis to distinguish between more aggressive and less aggressive form is based on post-surgical histological examination and no molecular biomarkers for early detection are available.

Methods

Quantitative polymerase chain reaction (qPCR) analysis of 11 metabolic genes involved in general and adipose tissue-specific metabolism, was performed on ALT (= 8), WDLPS (= 9) and DDLPS (= 20) samples. Subsequent statistical analysis was carried out to determine genes that most accurately can predict DDLPS differential diagnosis. Selected genes were further validated in a separate cohort by qPCR and the data statistically analysed. Deep sequencing was performed on DDLPS specimen from the metastatic patient and on five random WDLPS specimens.

Results

We established a three-gene signature based on PNPLA2, LIPE and PLIN1, which identified DDLPS with 100% sensitivity and 90% specificity, even in specimens from the WD component of DDLPS tumors. Interestingly, the PNPLA2 gene is deleted in 45% of DDLPS samples analyzed under TCGA project, and the deletion is associated with significantly lower PNPLA2 expression level. However, other mechanisms causing loss or downregulation of the expression of these three genes may be involved. Moreover, the significantly lower level of PNPLA2 is associated with R1 surgical margins, compare to R0 margins, which suggests the more invasive tumor phenotype in the absence of PNPLA2.

Conclusions

The identified metabolic signature allows highly accurate differential diagnosis between WD- and DDLPS even in samples containing lipid droplets, a marker of differentiation, which makes it very suitable for the use on biopsies. In respect to the pathogenesis of the disease, our results give a new insight into possible molecular mechanisms involved and support the recent observation that deletion of PNPLA2 is a novel factor in liposarcoma progression.

[French ccAFU guidelines - Update 2018-2020: Retroperitoneal sarcoma]

OBJECTIVE

To update French urological guidelines on retroperitoneal sarcoma.

METHODS

Comprehensive Medline search between 2016 and 2018 upon diagnosis, treatment and follow-up of retroperitoneal sarcoma. Level of evidence was evaluated.

RESULTS

Chest, abdomen and pelvis CT is mandatory to evaluate any suspected retroperitoneal sarcoma. MRI sometimes helps surgical planning. Before histological confirmation through biopsy, the patient must be registered in the French sarcoma pathology reference network. The biopsy standard should be an extraperitoneal coaxial percutaneous sampling before any retroperitoneal mass therapeutic decision. Surgery is retroperitoneal sarcoma cornerstone. The main objective is grossly negative margins and can be technically challenging. Multimodal treatment risks and benefits must be discussed in multidisciplinary teams. The relapse rate is related to tumor grade and surgical margins.

CONCLUSION

Retroperitoneal sarcoma prognosis is poor and closely related to the quality of initial management. Centralization through dedicated sarcoma pathology network in a high-volume center is mandatory.

Leiomyosarcoma of the Inferior Vena Cava with Hepatic and Pulmonary Metastases: Case Report

Sarcomas are connective tissue tumors accounting for only 1% of all adult malignancies. Leiomyosarcoma (LMS) is a sarcoma arising from smooth muscle cells, and accounts for 10-20% of all sarcomas. A subtype of LMS are those originating from the smooth muscle of blood vessels. Leiomyosarcoma of the inferior vena cava is a sarcomatous tumor, with less than 350 cases described in the literature. It carries a poor prognosis, with 5- and 10-year survival rates of 31.4% and 7.4%, respectively. We present a case of a 46-year-old female with no significant past medical history presented to the emergency department with mild abdominal pain and distention, early satiety, and weight loss for three weeks, found to have unresectable metastatic leiomyosarcoma of the inferior vena cava.

Iatrogenic Vascular Injuries of the Abdomen and Pelvis: The Experience at a Hellenic University Hospital

Background:

The aim of this study is to present the experience of a Vascular Division at a Hellenic University hospital concerning the management of iatrogenic vascular injuries (IVIs) of the abdomen or pelvis.

Patients and Methods:

This is a retrospective study evaluating all IVIs reported during a 10-year period in our institution. Only injuries warranting a vascular surgeon consultation were included in the study. Non-iatrogenic injuries were not included. Mortality and major complications within 30 days were evaluated.

Results:

Overall, 70 cases were recorded, with 41% being venous and 59% being arterial injuries. Iliac arteries (51%) were the most common location and rupture/lacerations (73%) were the most common type of injury. General surgery (61.5%) and cardiology (30%) procedures were the most frequently involved procedures. A 30-day mortality was 5.7%, with 30% of cases treated conservatively. Synthetic bypass grafting (odds ratio [OR] = 65.0; 95% confidence interval [CI], 4.022-1050.358; P = .003) and male gender (OR = 83.77; 95% CI, 4.040-1736.738; P = .004) were associated with death.

Conclusions:

Iatrogenic vascular injuries of the abdomen or pelvis are usually associated with general surgery and endovascular procedures. When vascular consultation is requested early, mortality could remain low. However, a selected number of stable patients with retroperitoneal or pelvic hematomas could be treated conservatively, yielding satisfying results.

RETRACTED: Recommandations françaises du Comité de Cancérologie de l’AFU — Actualisation 2018—2020 : sarcomes rétropéritonéaux French ccAFU guidelines — Update 2018—2020: Retroperitoneal sarcoma

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). Cet article est retiré de la publication à la demande des auteurs car ils ont apporté des modifications significatives sur des points scientifiques après la publication de la première version des recommandations. Le nouvel article est disponible à cette adresse: doi:10.1016/j.purol.2019.01.010. C’est cette nouvelle version qui doit être utilisée pour citer l’article. This article has been retracted at the request of the authors, as it is not based on the definitive version of the text because some scientific data has been corrected since the first issue was published. The replacement has been published at the doi:10.1016/j.purol.2019.01.010. That newer version of the text should be used when citing the article.

Imaging in retroperitoneal soft tissue sarcoma

Patients with retroperitoneal sarcoma can present to a variety of clinicians with non‐specific symptoms and retroperitoneal sarcomas can be incidental findings. Failure to recognize retroperitoneal sarcomas on imaging can lead to inappropriate management in non‐specialist centers. Therefore it is critical that the possibility of retroperitoneal sarcoma should be considered with prompt referral to a soft tissue sarcoma unit. This review guides clinicians through a diagnostic pathway, introduces concepts in response assessment and new imaging developments.