Computed tomography scan-driven selection of treatment for retroperitoneal liposarcoma histologic subtypes

Survival analysis and prognostic factors of retroperitoneal liposarcoma curative surgery in a single centre. Analysis of adjacent organ invasion between imaging and definitive histopathology

INTRODUCTION

Retroperitoneal liposarcoma (RPL) is a rare primary mesenchymal tumour that develops in retroperitoneal adipose tissue. Unlike the majority of published series, this homogeneous cohort focuses on RPL. The main purpose of this study is to evaluate the overall and recurrence-free survival of RPLs who underwent excision surgery and the prognostic factors involved.

PATIENTS AND METHODS

A total of 82 patients from a single centre, who underwent curative surgery for histologically confirmed retroperitoneal liposarcoma between 2008 and 2020, were analysed in the study. Compartmental surgical excision was advised as per the guidelines. The primary endpoints were 5 years of overall survival and recurrence-free survival. Predictable tumour invasion of adjacent organs, based on a pre-operative CT scan, was also investigated to test the correlation between pre-operative imaging and pathological data.

RESULTS

Median follow-up was 61.6 months. Five year overall survival was 71.9% [95% CI: 59.8; 80.9] and 5 year recurrence-free survival was 49% [95% CI: 36.4; 60.5]. Following multivariable analysis, the factors influencing overall survival were tumour rupture and onset of severe complications (Dindo-Clavien grade ≥3). Factors influencing recurrence-free survival were neoadjuvant radiotherapy and tumour rupture. A significant correlation (p < 0.05) was found between predicted invasion based on a CT scan of the colon, spleen, adrenal gland, posterior abdominal wall and diaphragm, and pathological invasion.

CONCLUSIONS

Curative compartmental surgery remains the gold standard treatment for RPL. This study, highlights the fact that the quality of the surgical excision is a crucial factor in patient prognosis.

Which modality is better to diagnose high-grade transformation in retroperitoneal liposarcoma? Comparison of computed tomography, positron emission tomography, and magnetic resonance imaging

BACKGROUND

Survival in patients with retroperitoneal liposarcoma (RPLS) depends on the surgical management of the dedifferentiated foci. The present study investigated the diagnostic yield of contrast-enhanced CT, ¹⁸F-fluorodeoxyglucose positron emission tomography (PET), and diffusion-weighted MRI in terms of dedifferentiated foci within the RPLS.

METHODS

Patients treated with primary or recurrent RPLS who underwent the above imaging between January 2010 and December 2021 were retrospectively reviewed. The diagnostic accuracy of the three modalities for histologic subtype of dedifferentiated liposarcoma (DDLS) and French Federation of Cancer Center (FNCLCC) grade 2/3 were compared using receiver operating characteristic curves and areas under the curves (AUCs).

RESULTS

The cohort involved 32 patients with 53 tumors; 30 of which exhibited DDLS and 31 of which did FNCLCC grades 2/3. The optimal thresholds for predicting DDLS were mean CT value of 31 Hounsfield Unit (HU) (AUC = 0.880, 95% CI 0.775-0.984; p < 0.001), maximum standardized uptake value (SUVmax) of 2.9 (AUC = 0.865 95% CI 0.792-0.980; p < 0.001), while MRI failed to differentiate DDLS. The cutoff values for distinguishing FNCLCC grades 1 and 2/3 were a mean CT value of 24 HU (AUC = 0.858, 95% CI 0.731-0.985; p < 0.001) and SUVmax of 2.9 (AUC = 0.885, 95% CI 0.792-0.978; p < 0.001). MRI had no sufficient power to separate these grades.

CONCLUSIONS

Contrast-enhanced CT and PET were useful for predicting DDLS and FNCLCC grade 2/3, while MRI was inferior to these two modalities.

Treatment for local control of retroperitoneal and pelvis sarcomas: A review of the literature

Retroperitoneal and pelvis sarcomas are uncommon tumors for which complete surgical resection is the mainstay of treatment. However, achieving complete gross resection with microscopically negative margins is challenging, and local recurrence rates can be high. Patients often succumb to uncontrolled local disease. Radiation therapy offers a potential means for sterilizing microscopic residual disease, although its use continues to be controversial. Chemotherapy alone or in combination with radiation continues to be investigated as an adjunct to surgery, along with immunotherapy and targeted therapies. In this review, we discuss the current management of retroperitoneal and pelvis sarcomas, focusing on studies of surgery and radiation therapy to maximize local control.

Virtual Biopsy in Soft Tissue Sarcoma. How Close Are We?

A shift in radiology to a data-driven specialty has been unlocked by synergistic developments in imaging biomarkers (IB) and computational science. This is advancing the capability to deliver "virtual biopsies" within oncology. The ability to non-invasively probe tumour biology both spatially and temporally would fulfil the potential of imaging to inform management of complex tumours; improving diagnostic accuracy, providing new insights into inter- and intra-tumoral heterogeneity and individualised treatment planning and monitoring. Soft tissue sarcomas (STS) are rare tumours of mesenchymal origin with over 150 histological subtypes and notorious heterogeneity. The combination of inter- and intra-tumoural heterogeneity and the rarity of the disease remain major barriers to effective treatments. We provide an overview of the process of successful IB development, the key imaging and computational advancements in STS including quantitative magnetic resonance imaging, radiomics and artificial intelligence, and the studies to date that have explored the potential biological surrogates to imaging metrics. We discuss the promising future directions of IBs in STS and illustrate how the routine clinical implementation of a virtual biopsy has the potential to revolutionise the management of this group of complex cancers and improve clinical outcomes.

Hyper-accuracy three-dimensional reconstruction as a tool for better planning of retroperitoneal liposarcoma resection: A case report

BACKGROUND

Well-differentiated liposarcoma is the second most common pathologic type of retroperitoneal sarcoma. It is characterized by a huge mass, but multiple organ invasions are common. Surgery is the only treatment option for potential cure. Hyper-accuracy three-dimensional (3D) reconstruction is widely used in robotic partly nephrectomy owing to its ability to visualize overlapping anatomy.

CASE SUMMARY

A 54-year-old man was admitted for progressive abdominal distension over the preceding 2 mo. Computed tomography revealed a 32 cm × 21 cm × 12 cm lipomatous mass. Hyper-accuracy 3D reconstruction was performed because of the complex relationship between the mass and nearby tissue. The patient underwent surgical resection, and the tumor did not recur for over 16 mo.

CONCLUSION

Hyper-accuracy 3D reconstruction is useful for operative planning owing to its intuitiveness and precise determination of anatomical structures in both tumors and nearby tissues.

Clinical characteristics, treatment strategies and oncologic outcomes of primary retroperitoneal tumours: a retrospective analysis in the Chinese population

INTRODUCTION

Primary retroperitoneal tumours (PRTs) are rare soft tissue tumours originating from the retroperitoneum. Although there has been considerable progress recently in diagnosis and treatment, the overall survival rate has not improved qualitatively. This study aimed to explore the clinical features, therapeutic strategies and prognosis of PRTs.

METHODS

Retrospective analysis of clinical data for 121 PRT patients admitted to Peking University Shenzhen Hospital from April 2003 to February 2017.

RESULTS

A total of 113 patients underwent surgery and 8 chose nonsurgical palliative treatment. There were 53 males and 68 females (ratio, 1:1.3; average age, 40.75 years), and the average tumour diameter was 9.69(2-40)cm. A total of 104 patients (92.04%) underwent complete resection, 5 (4.42%) underwent palliative resection and 21 (18.58%) underwent combined visceral resection. The pathological diagnosis was benign in 88 cases (72.73%) and malignant in 33 cases (27.27%). A total of 101 patients (83.47%) were followed for an average of 5.82 years. At the end of follow up, the recurrence and survival rates were 2.63% and 93.42% for benign tumours, respectively, and 24.00% and 60.00% for malignant tumours (p<0.01).

CONCLUSIONS

Imaging plays important roles in localising and characterising tumours, guiding treatment strategies. Complete tumour resection is key to reducing postoperative recurrence and improving survival. According to the postsurgical pathological results, combinations including radiotherapy, chemotherapy or targeted therapy are beneficial for improving prognosis.

Role of Radiation Therapy for Newly Diagnosed Retroperitoneal Sarcoma

OPINION STATEMENT

Soft tissue sarcomas (STS) are rare, aggressive, and heterogenous tumors, comprising approximately 1% of adult cancers with over 50 different subtypes. The mainstay of treatment for retroperitoneal sarcomas (RPS) includes surgical resection. The addition of radiation therapy (RT), either preoperatively or postoperatively, has been used to potentially decrease the risk of local recurrence. The recently published results from STRASS (EORTC-STBSG 62092-22092), which randomized patients to receive or not receive preoperative radiation, indicate no abdominal recurrence-free survival benefit (primary endpoint) nor overall survival benefit to date from the addition of preoperative RT prior to surgical resection in patients with RPS. Keeping in mind caveats of subgroup analyses, the data show a significant reduction in local recurrence with radiation therapy in resected patients and non-significant trends toward improved abdominal recurrence-free survival in all patients and improved local control and abdominal recurrence-free survival in patients with liposarcoma and low-grade sarcoma. Given the high rate of local failure with surgery alone, it is possible that higher RT dose and/or selective RT dose painting may improve outcomes. Prior to treatment, the authors encourage multidisciplinary review and discussion of management options at a sarcoma center for patients with RPS. Selective use of RT may be considered for patients at high risk of local recurrence.

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.

Diagnostic approach to primary retroperitoneal pathologies: what the radiologist needs to know

Retroperitoneal soft tissue lesions represent a wide range of disease processes with overlapping imaging findings. Familiarity with the CT and MR characteristics of these conditions is important to guide clinical evaluation. We review the tissue types, characteristic clinical, demographic, and imaging features of retroperitoneal tumors and tumor-like non-neoplastic conditions with CT and MR correlation, including anatomic and imaging clues, and provide a diagnostic approach to aide the radiologist in making a specific diagnosis.

Preoperative Biopsy in Patients with Retroperitoneal Sarcoma: Usage and Outcomes in a National Cohort

INTRODUCTION

Preoperative biopsy (PBx) is often recommended for retroperitoneal sarcoma (RPS), but its utilization rate and impact on perioperative management and outcomes remains undefined.

METHODS

Using the National Cancer Database, patients who underwent resection of non-metastatic RPS were identified (2006-2014). Patients who did and did not undergo PBx of the primary tumor were compared using propensity matching, and factors associated with survival were assessed by multivariable analysis.

RESULTS

Of 2620 patients, 1110 (42.4%) underwent PBx. Factors significantly associated with performance of PBx included male sex [odds ratio (OR) 1.2, P = 0.035], tumor size ≤ 5 cm (OR 1.5, P = 0.012), tumor size > 5 to ≤ 10 cm (OR 1.3, P = 0.009), non-well-differentiated liposarcoma histology (OR 2.0, P ≤ 0.001), and treatment at a high-volume center (OR 1.3, P = 0.021). Receipt of PBx was significantly associated with administration of neoadjuvant radiation (OR 8.8, P < 0.001) or systemic therapy (OR 3.3, P < 0.001), radical surgical resection (OR 1.6, P < 0.001), and complete tumor resection (OR 1.5, P < 0.003). Neoadjuvant radiation [hazard ratio (HR) 0.7, P = 0.003] and complete tumor resection (HR 0.6, P < 0.001) were significantly associated with improved overall survival (OS). Performance of PBx was not associated with OS (HR 1.1, P = 0.070), and following propensity matching, 5-year OS did not differ between the two groups (56.5% PBx vs 58.4% no PBx, P = 0.247).

CONCLUSIONS

A minority of patients with non-metastatic RPS undergo PBx. PBx does not negatively impact survival, but may indirectly improve outcomes in select patients by virtue of receipt of neoadjuvant therapy and attainment of complete tumor resection.

Prediction of Histologic Subtype and FNCLCC Grade by SUVmax Measured on 18F-FDG PET/CT in Patients with Retroperitoneal Liposarcoma

This study aimed to evaluate the usefulness of maximum standardized uptake value (SUVmax) on ¹⁸F-fluorodeoxyglucose positron emission tomography with computed tomography (¹⁸F-FDG PET/CT) in differentiating the subtypes and tumor grades of retroperitoneal liposarcoma (RPLS). The data of RPLS patients who underwent surgical resection from November 2013 to December 2019 at the sarcoma center of our institute were reviewed. The demographics, clinical features, and SUVmax of 84 patients who underwent preoperative ¹⁸F-FDG PET/CT scans were analyzed. Of these, 19 patients (22.6%) were with well-differentiated liposarcoma (WDLPS), 60 patients (71.4%) were with dedifferentiated liposarcoma (DDLPS), and 5 patients (6.0%) were with pleomorphic liposarcoma (PMLPS). The median SUVmax of WDLPS, DDLPS, and PMLPS groups was 2.8 (IQR: 1.9-3.2), 6.2 (IQR: 4.1-11.3), and 4.5 (IQR: 4.0-7.4). The ROC curve suggested 3.8 as an approximate cutoff value of SUVmax for distinguishing WDLPS and non-WDLPS (sensitivity = 0.769; specificity = 0.895). The median SUVmax for FNCLCC Grades 1, 2, and 3 of RPLS was 2.5 (IQR: 1.9-3.2), 4.5 (IQR: 3.2-6.7), and 9.0 (IQR: 6.0-13.3). The ROC curves suggest that SUVmax of ≤3.8 and >5.3 can be used for predicting FNCLCC Grades 1 and 3, respectively. The result showed that ¹⁸F-FDG PET/CT exhibited high sensitivity and specificity for identifying the subtypes and FNCLCC grades of RPLS. Additionally, ¹⁸F-FDG PET/CT might be a useful complementary imaging modality for guiding suitable biopsy location of RPLS.

Conditional survival after surgical resection of primary retroperitoneal tumors: a population-based study

Background

The purpose of this study was to assess conditional survival (CS) after resection of primary retroperitoneal tumors (RPTs).

Methods

The data of 1594 patients with primary RPTs who underwent surgery between 2004 and 2016 were retrieved from the Surveillance Epidemiology and End Results (SEER) database. Multivariate Cox analysis was used to identify prognostic factors affecting overall survival (OS) and cancer-specific survival (CSS). CS was used to calculate the probability of survival for an additional 3 years after the patient had survived x years, according to the formulas: COS3 = OS (x + 3) /OS (x) and CCSS3 = CSS (x + 3)/CSS (x).

Results

The 1-, 3-, and 5-year OS rates of all patients were 89.8, 71.8, and 60.8%, while the 1-, 3-, and 5-year CSS rates were 91.9, 77.1, and 67.8%, respectively. Age, sex, FNCLCC grade, size, multifocality, histology, and chemotherapy were independent prognostic factors for OS and CSS. Among patients who survived for 1, 3, and 5 years, the COS3 rates were 72.9, 77.9, and 79.3%, and the CCSS3 rates were 78.1, 82.7, and 85.8%, respectively. Patients with poor clinicopathological characteristics achieved greater improvements in COS3 and CCSS3 rates, and the survival gaps between OS and COS3, as well as CSS and CCSS3 were more obvious.

Conclusion

Postoperative CS of RPTs was dynamic and increased over time. CS increased more significantly in patients with poor clinicopathological characteristics.

Changes of the hepatic subcapsular blood flow in a case of high-grade retroperitoneal liposarcoma: what to expect?

Changes of the hepatic subcapsular blood flow with the early appearance of hypervascularity near the falciform ligament are rare radiologic findings. They present most frequently in cases of superior vena cava (SVC) obstruction and are related to the recruitment of the cavo-mammary-phrenic-hepatic-capsule-portal and the cavo-superficial-umbilical-portal pathways. We present the case of a 52-year-old female patient with an highly aggressive retroperitoneal liposarcoma with SVC obstruction caused by external compression due to a mediastinal metastatic mass. The patient exhibited no symptoms of SVC obstruction due to the collateral cavo-portal pathways.

Minimally Invasive Surgery of Primary Retroperitoneal Tumors from the Perspective of General Surgeons: 6 Years of Experience at a Single Institution

Objective: This retrospective study aimed to present our surgical experience in patients with primary retroperitoneal tumors (PRTs) who underwent laparoscopic surgery and to compare the results with those of patients who underwent an open operation. Materials and Methods: We analyzed the medical data of patients who underwent retroperitoneal tumor resection through laparoscopic surgery or open operation between February 2014 and November 2019. Results: In total, 77 patients were enrolled. In total, 37 patients underwent open surgery and 40 patients underwent laparoscopic surgery. The tumor size in the open surgery group (10.2 ± 5.4 cm) was more significant than that in the laparoscopic surgery group (6.5 ± 3.1 cm) (P < .001). No difference was observed in operative time, blood loss, and transfusion between the two groups. Postoperative hospitalization in the open group (8.43 ± 2.77 days) was longer than that in the laparoscopic group (5.63 ± 2.16 days) (P < .001). The patients with PRTs in the IV area had minimal bleeding (16.67 ± 40.82 mL) and minimum postoperative hospitalization (3.83 ± 1.60 days). Conclusions: Laparoscopic resection of PRT is feasible in the selection of appropriate cases. The advantages are small trauma, light pain, quick recovery, and short hospital stay. It is especially suitable for benign PRTs with small size and cystic or small adhesion with vital organs or great vessels.

PET/CT Imaging as a Diagnostic Tool in Distinguishing Well-Differentiated versus Dedifferentiated Liposarcoma

Distinguishing well-differentiated liposarcoma (WDLPS) from dedifferentiated liposarcoma (DDLPS) is essential given distinct treatment paradigms and chemosensitivity. Percutaneous biopsy has a low sensitivity for detecting DDLPS. We sought to identify the diagnostic utility of positron emission tomography/computed tomography (PET/CT) in identifying WDLPS versus DDLPS. An independent radiologist reviewed PET/CT images to identify target lesions and determine the maximum standardized uptake value (SUVmax). An independent pathologist review confirmed WDLPS or DDLPS histology. A binary cutoff point of SUVmax was identified using a classification and regression trees (CART) algorithm. We identified 20 patients with WDLPS or DDLPS with 26 PET/CTs performed for separate recurrences that were followed by surgical sampling. Of the 26 records, 12 were DDLPS (46%) and 14 were WDLPS (54%). Patients with DDLPS had significantly higher SUVmax than those with WDLPS (p value = 0.0035). A SUVmax of 4 was identified as the cutoff point. Using this cutoff, the sensitivity of SUVmax identifying a case as DDLPS was 83.3% (95% CI: 51.6%, 97.9%) and the specificity was 85.7% (95% CI: 57.2%, 98.2%). PET/CT is a sensitive and specific diagnostic tool to identify the presence of dedifferentiation within the tumor.

Improved Biopsy Accuracy in Retroperitoneal Dedifferentiated Liposarcoma

BACKGROUND

Biopsy sensitivity in retroperitoneal dedifferentiated liposarcoma (DDLPS) is variable. Patients with grade 3 DDLPS face a significant risk of metastatic disease and may potentially benefit from neoadjuvant therapy, making highly accurate pretherapy diagnosis essential. Our study aimed to establish whether diagnostic sensitivity could be improved by targeting solid areas of tumor on percutaneous biopsy.

METHODS

Between 2016 and 2019, data on patients with suspected primary retroperitoneal sarcoma who underwent a biopsy were collected, and diagnostic accuracy was calculated. These data were compared with our previously reported series from 2005 to 2016. For DDLPS tumors, comparisons were then made between biopsies that targeted the solid component and those that did not.

RESULTS

Data were available for 121 patients in the current series and 238 from the previous study. The proportion of biopsies returning a histological subtype concordant with postoperative pathology was 83% in the current series, marking a significant improvement over our previous study (67%, p = 0.001). For diagnosis of DDLPS, biopsy sensitivity improved from 40 to 74% (p < 0.001), with an increase from 13 to 50% (p = 0.006) where grade 3 DDLPS was treated as a separate disease. Within the current series, targeted biopsy yielded a sensitivity of 100% for identifying DDLPS, compared with 10% in nontargeted biopsy (p < 0.001).

CONCLUSION

Systematic targeting of solid areas of tumor within suspected retroperitoneal liposarcoma has improved sensitivity for detection of both DDLPS and grade 3 DDLPS on biopsy. This approach minimizes the risk of underdiagnosis of patients with DDLPS who could benefit from neoadjuvant chemotherapy.

Laparoscopic approach to an incidentally found pelvic retroperitoneal liposarcoma: Case report and review

RATIONALE

Well-differentiated liposarcomas (WDLPS) are rare retroperitoneal tumors that can reach significant size as they can grow without constrains before becoming symptomatic. Laparotomic open radical tumor resection represents the most common surgical approach.

PATIENT CONCERNS

A mass with "fat fluid level" was found in the right pelvis of an asymptomatic woman undergoing routine transvaginal ultrasound: the preoperative diagnosis was right mature ovarian teratoma.

DIAGNOSIS

Postoperative histopathology confirmed the diagnosis of WDLPS.

INTERVENTIONS

A radical laparoscopic excision of the retroperitoneal mass with bilateral salpingectomy was performed.

OUTCOMES

Patient is free of disease at 18 months after surgery.

LESSON

Despite computed tomography scan is the gold standard technique to identify WDLPS, such neoplasms can be misdiagnosed for mature ovarian teratomas. When a retroperitoneal mass is incidentally discovered during a surgery, an open core-needle biopsy is usually performed, and appropriate treatment planned only after complete staging and final pathology are available. Instead, when tumor margins are identified, resection of an incidentally diagnosed WDLPS would benefit from laparoscopic magnification that could improve distinguishing the disease from the surrounding tissues. Therefore, laparoscopy could represent a safe and effective technique to diagnose and treat retroperitoneal diseases.

Management of primary retroperitoneal synovial sarcoma: A case report and review of literature

BACKGROUND

Synovial sarcoma (SS) is a rare type of soft tissue sarcoma that is usually developed from areas where synovial tissue exists, especially at the extremities. Nevertheless, several cases of retroperitoneal SS (RSS) have been described. We herein report a case of RSS presented in our institution.

CASE SUMMARY

A 69-year-old female patient was admitted with a large, palpable, firm mass in the right abdominal space SS. Computerized tomography scan depicted a concentric, sharply marinated retro-peritoneal lesion which was displacing the right kidney and the lower edge of the liver. Subsequently, the patient underwent surgical excision of the mass with additional right nephrectomy and resection of the right adrenal gland and a part of the diaphragm. The final histological diagnosis of the tumour was grade II monophasic RSS.

CONCLUSION

RSS is encountered in the biphasic type, the monophasic fibrous, and the monophasic epithelial category as well. Relevant clinical manifestations are not always documented at early stages. Therefore, the final diagnosis is posed after complete histological examination taking into consideration the results of immunochemistry and genetic analysis. Therapeutic approach happens often late when metastases at the lungs and the liver are apparent. Thus, 5-year survival rates remain low.

Diagnostic accuracy of percutaneous biopsy in retroperitoneal sarcoma

Background

Percutaneous biopsy is recommended before surgery for suspected retroperitoneal sarcoma (RPS) to confirm the histological diagnosis and guide surgical strategy. The present study aimed to establish the diagnostic accuracy of percutaneous core biopsy with respect to histological diagnosis and tumour grade.

Methods

Data on patients with suspected RPS who underwent percutaneous biopsy followed by surgical resection between 2005 and 2016 at one of two tertiary European sarcoma units were reviewed. Histological tumour type and tumour grade on biopsy were correlated with postoperative histology to evaluate diagnostic accuracy.

Results

A total of 239 patients underwent percutaneous core biopsy followed by surgical resection in Milan (163, 68·2 per cent) or Birmingham (76, 31·8 per cent). Diagnostic accuracy varied with histological diagnosis (P &lt; 0·001), but demonstrated overall concordance with final pathology following resection in 67·2 per cent of biopsies (κ = 0·606). The majority of discrepancies occurred in dedifferentiated liposarcoma (DDLPS), owing to under-recognition of dedifferentiation in this group. Concordance between pathology on biopsy and resection improved to 81·1 per cent when DDLPS and well differentiated liposarcoma were grouped together as liposarcoma. Grade on biopsy was concordant with grade on resection specimen in 60·4 per cent of tumours (κ = 0·640). Diagnosis of high-grade tumours on biopsy had a high specificity (98 per cent), and moderate positive predictive value (85 per cent) and negative predictive value (78 per cent).

Conclusion

A diagnosis of DDLPS or leiomyosarcoma on percutaneous biopsy is highly reliable. High-grade sarcomas can be identified with high specificity, which opens the door to a study on neoadjuvant therapy in these patients.

Integrating therapies for surgical adult soft tissue sarcoma patients

Sarcomas are an uncommon group of over 50 different individual histological malignancies arising from mesenchymal (non-epithelial or connective) tissues. Overall, they constitute 1% of human malignancies with an annual incidence rate of fewer than 5 patients per million. Sarcoma may arise from any mesenchymal cell lineages including fat, muscle, or other connective tissues. Due to the rarity of these groups of malignancies, many subtypes were, and still today, are managed as a single entity. This review focused on soft tissue sarcomas with an emphasis on how to integrate therapies for patients with this rare disorder. The role for surgical resection in cure and palliation as well as the relative benefits of adjuvant therapies such as chemotherapy and radiation therapy are discussed.

Surgery for Abdominal Well-Differentiated Liposarcoma

OPINION STATEMENT

Retroperitoneal sarcomas are rare tumors of which liposarcoma is the most common histology. Surgical resection remains the mainstay of therapy, particularly for the well-differentiated subtype. They can grow to massive size before causing symptoms or detection. Well-differentiated liposarcoma, while having a negligible metastatic rate, is fraught with a high local recurrence rate, despite a complete surgical resection. Reasons for this are not completely known but may be related to a field defect of the retroperitoneal fat creating a niche for recurrence. These tumors are classically chemo- and radio-resistant. Surgical therapy of recurrences can be challenging, but remains the treatment of choice for well-differentiated liposarcoma. In an attempt to improve on survival and recurrence rates for retroperitoneal liposarcoma, an extended resection approach has been promoted by a few groups. This involves the en bloc resection of contiguous organs that are not macroscopically involved. While this has improved local recurrence rates, benefit for overall survival has not been demonstrated. Interestingly, the improvement in local recurrence rate appeared to be driven by histology and was most improved in the well-differentiated subtype compared to historical data. However, for well-differentiated liposarcomas that are multifocal, this approach may be less useful. The application of this approach still requires further study in terms of balancing increased morbidity of extended resection against the potential for multiple surgeries for recurrence.

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.

Clinicopathological characteristics and experience in the treatment of giant retroperitoneal liposarcoma: A case report and review of the literature

Retroperitoneal liposarcoma (RPLS) is a rare tumor, especailly those over 20 kg that are called "giant liposarcoma," whose characteristics and treatments remain relatively unknown. Herein, we report a giant RPLS measuring 65 × 45 × 30 cm in diameter and 31 kg in weight, which we successfully performed complete excision through interdisciplinary cooperation. The patient had an uneventful postoperative course and was discharged without complications. Afterwards he underwent radiotherapy and had no evidence of tumor recurrence or symptoms of metastasis at 3-month CT scan and 8-month follow-up. We also first review the 13 cases reported in literature published in PubMed regarding giant RPLS. Giant RPLS commonly occurs in adults aged 40-60 y and presents atypical clinical manifestations. CT scan is the most useful examination and preoperative biopsy is controversial. Complete surgical resection still remains the principal treatment. Giant RPLS can also be removed, even reach to R0 excision, by a multidisciplinary team in a specialized center after meticulous planning even though its gigantic tumor size. Local radiotherapy following surgery may improve the rate of recurrence. Besides, closely follow-up and routine examinations are required.

Can Abdominal Computed Tomography Imaging Help Accurately Identify a Dedifferentiated Component in a Well-Differentiated Liposarcoma?

PURPOSE

To assess the ability of computed tomography (CT) to differentiate an atypical lipomatous tumor/well-differentiated liposarcoma (WDLPS) from a WDLPS with a dedifferentiated component (DDLPS) within it.

MATERIALS AND METHODS

Forty-nine untreated patients with abdominal atypical lipomatous tumors/well-differentiated liposarcomas who had undergone contrast-enhanced CT were identified using an institutional database. Three radiologists who were blinded to the pathology findings evaluated all the images independently to determine whether a dedifferentiated component was present within the WDLPS. The CT images were evaluated for fat content (≤25% or >25%); presence of ground-glass density, enhancing and/or necrotic nodules; presence of a capsule surrounding the mass; septations; and presence and pattern of calcifications. A multivariate logistic regression model with generalized estimating equations was used to correlate imaging features with pathology findings. Kappa statistics were calculated to assess agreement between the three radiologists.

RESULTS

On the basis of pathological findings, 12 patients had been diagnosed with DDLPS within a WDLPS and 37 had been diagnosed with WDLPS. The presence of an enhancing or a centrally necrotic nodule within the atypical lipomatous tumor was associated with dedifferentiated liposarcoma (P = 0.02 and P = 0.0003, respectively). The three readers showed almost perfect agreement in overall diagnosis (κ r = 0.83; 95% confidence interval, 0.67-0.99).

CONCLUSIONS

An enhancing or centrally necrotic nodule may be indicative of a dedifferentiated component in well-differentiated liposarcoma. Ground-glass density nodules may not be indicative of dedifferentiation.

Characteristics and computed tomography evaluation of primary retroperitoneal tumours: report of 113 cases

INTRODUCTION Benign and malignant primary retroperitoneal tumours (PRT) have different clinical manifestations and pathological characteristics. We explore the characteristics and evaluate the value of computed tomography (CT) for PRT. METHODS Fifty-six benign and fifty-seven malignant PRT with clinical, radiographic and surgical data were retrospectively investigated. Statistical analysis was carried out using SPSS software. RESULTS We found that mean size of benign tumours was 12.4 ± 7.7cm but 20.7 ± 11.6cm in malignant cases (P < 0.05). The accuracy of CT localisation was approximately 70%. The sensitivity and specificity of CT diagnosis for benign tumours were 96% and 85%, respectively; 51 (91%) underwent complete resection among benign cases but 42 (74%) in malignant cases (P < 0.05). Sensitivity of CT evaluation for invaded organs and vessels was 50% and 65%, respectively, and specificity was 88% and 81%, respectively. CONCLUSIONS Large size, no capsule, irregular margin, heterogeneous density and specific enhancement pattern on CT are highly suggestive of malignancy. CT is the most useful tool in assessing the size and characteristics of PRT but it does not have the sensitivity to assess the involvement of organs and vessels.

Primary retroperitoneal soft tissue sarcoma: Imaging appearances, pitfalls and diagnostic algorithm

Although retroperitoneal sarcomas are rare tumours, they can be encountered by a wide variety of clinicians as they can be incidental findings on imaging or present with non specific symptoms and signs. Surgical resection can offer hope of cure and patient outcomes are improved when patients are managed in high-volume specialist centers. Failure to recognize retroperitoneal sarcomas on imaging can lead to inappropriate management in inexperienced centers. Therefore it is critical that a diagnosis of retroperitoneal sarcoma should be considered in the differential diagnosis of a retroperitoneal mass with prompt referral to a soft tissue sarcoma unit. In particular, the most common retroperitoneal sarcoma subtypes, liposarcoma and leiomyosarcoma, have characteristic imaging appearances which are discussed. This review therefore aims to set the context and guide clinicians through a diagnostic pathway for retroperitoneal masses in adults which arise extrinsic to the solid abdominal viscera.

[Radiotherapy for retroperitoneal sarcomas]

The management of retroperitoneal sarcoma can be very challenging, and the quality of initial treatment strategy appears to be a crucial prognostic factor. En bloc surgery is currently the standard of care for these rare tumours and perioperative treatments such as chemotherapy or radiotherapy have not been validated yet. However, local-regional relapse constitutes the most common disease course. While adjuvant radiotherapy is less and less common due to gastrointestinal toxicities, preoperative radiation therapy offers numerous advantages and is being evaluated as part of a national multicentre phase II study (TOMOREP trial) and is the subject of a European randomized phase III study (STRASS trial). The objective of this article is to present data on preoperative irradiation in terms of dose, volumes and optimal radiotherapy techniques for the treatment of this rare disease.

Management of Recurrent Retroperitoneal Sarcoma (RPS) in the Adult: A Consensus Approach from the Trans-Atlantic RPS Working Group

INTRODUCTION

Retroperitoneal soft tissue sarcomas (RPS) are rare tumors. Surgery is the mainstay of curative therapy, but local recurrence is common. No recommendations concerning the best management of recurring disease have been developed so far. Although every effort should be made to optimize the initial approach, recommendations to treat recurring RPS will be helpful to maximize disease control at recurrence.

METHODS

An RPS transatlantic working group was established in 2013. The goals of the group were to share institutional experiences, build large multi-institutional case series, and develop consensus documents on the approach to this difficult disease. The outcome of this document applies to recurrent RPS that is nonvisceral in origin. Included are sarcomas of major veins, undifferentiated pleomorphic sarcoma of psoas, ureteric leiomyosarcoma (LMS). Excluded are desmoids-type fibromatosis, angiomyolipoma, gastrointestinal stromal tumors, sarcomas arising from the gut or its mesentery, uterine LMS, prostatic sarcoma, paratesticular/spermatic cord sarcoma, Ewing sarcoma, alveolar/embryonal rhabdomyosarcoma, sarcoma arising from teratoma, carcinosarcoma, sarcomatoid carcinoma, clear cell sarcoma, radiation-induced sarcoma, paraganglioma, and malignant pheochromocytoma.

RESULTS

Recurrent RPS management was evaluated from diagnosis to follow-up. It is a rare and complex malignancy that 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, but some patients may experience prolonged disease control also at recurrence, when the approach is optimized and follows the recommendations contained herein.

CONCLUSIONS

International collaboration is critical for adding to the present knowledge. A transatlantic prospective registry has been established.

Primary lesser sac myxoid liposarcoma: A case report

INTRODUCTION

Lesser sac pathological entities are uncommon. Most of these are tumors and are generally misdiagnosed as retroperitoneal lesions.

CASE REPORT

A 62year old male with past history of treated hypopharyngeal cancer presented with progressive abdominal distension. Physical examination revealed a midline intra abdominal mass in the epigastrium and umbilical region. Radiological investigations were suggestive of a retroperitoneal tumor,an image guided biopsy was reported as atypical lipoma. Surgical exploration confirmed a large multi lobulated tumor arising primarily from the lesser sac, post operative histopathological examination confirmed a myxoid liposarcoma.

DISCUSSION

Primary lesser sac tumors are rare, a literature review of primary lesser sac tumors with particular reference to myxoid liposarcoma is presented.

CONCLUSION

Primary lesser sac liposarcomas are rare neoplasms. The myxoid variant is unique for its peculiar biological behavior, in its sensitivity to chemotherapy and radiotherapy and for the presence of specific cytogenetic marker.

Primary Retroperitoneal Tumor with Unexpected Gingival Involvement

Retroperitoneal tumors present diagnostic challenges, although a definitive diagnosis can be established based on a histopathological analysis. We herein report the case of a 62-year-old woman with a massive retroperitoneal tumor who was referred to our department for surgery. Although we initially planned to perform an incisional biopsy, we unexpectedly detected gingival swelling, and a gingival biopsy subsequently confirmed a pathological diagnosis of Burkitt's lymphoma (BL). We successfully avoided the use of more invasive diagnostic procedures and were able to promptly initiate chemotherapy. Obtaining an immediate pathological diagnosis is essential for providing successful treatment in such cases, as the disease is potentially curable with chemotherapy. BL should therefore be considered in the differential diagnosis of massive retroperitoneal tumors, highlighting the importance of routine systemic screening.

Role of radiation therapy for non-extremity soft tissue sarcomas

BACKGROUND

Negative surgical margins are uncommon for non-extremity soft tissue sarcomas. Radiation therapy is usually recommended to improve local control; however, appropriate RT dosing is challenging due to nearby dose-limiting normal structures.

MATERIAL AND METHODS

Comprehensive literature search using PubMed (March 2014).

RESULTS

Data suggest radiation therapy is an important modality in maximizing local tumor control in non-extremity sarcomas.

CONCLUSION

The literature supports the use of RT to improve local control for non-extremity soft tissue sarcomas.

Surgical management of retroperitoneal and pelvic sarcomas

Management of retroperitoneal sarcomas presents technical and oncological challenges. Imaging is crucial for diagnosis and to define local tumor extent. Complete gross resection at initial presentation is the best chance for cure, but there is controversy as to how this can be best achieved. There is a long-term risk of local recurrence, which is best treated with repeat resection if feasible. The roles of radiation and chemotherapy remain undefined.

Suprarenal retroperitoneal liposarcoma with intracaval tumor thrombus: an imaging mimic of adrenocortical carcinoma

We report a 57-year-old previously healthy man who presented with dull right upper quadrant pain, weight loss, fatigue, and night sweats. Computed tomography demonstrated a large, heterogeneously enhancing, soft tissue mass with no macroscopic fat above the right kidney with tumor thrombus extending into the inferior vena cava and right atrium. Positron Emission Tomography scanning demonstrated intense Fluorodeoxyglucose avidity in the primary tumor and tumor thrombus. The presumptive radiological diagnosis was adrenocortical carcinoma, but surgical pathology revealed a dedifferentiated liposarcoma. We conclude that suprarenal retroperitoneal liposarcoma should be included in the differential diagnosis for an apparent adrenal mass with venous invasion.

Current diagnosis and management of retroperitoneal sarcoma

BACKGROUND

Retroperitoneal sarcomas are rare neoplasms that often present with multivisceral involvement. Treatment for these tumors requires careful decision making requiring a combination of surgery, chemotherapy, and radiation therapy.

METHODS

We reviewed the scientific literature pertaining to the diagnosis and management of retroperitoneal sarcomas. We also identify recent developments in treatment and discuss future trends in the care of patients with this disease.

RESULTS

Retroperitoneal tumors often present as large, locally advanced lesions. Evaluation of these tumors requires careful consideration of a multimodality approach. Retrospective data and historical prospective series have demonstrated the survival benefit of radical resection for these tumors with en bloc resection of involved structures. Compartmental resections in the retroperitoneum along with debulking of high-grade disease and regional therapy are controversial approaches with significant morbidity that can lead to long-term survival. The application of neoadjuvant and adjuvant therapies in select tumor histologies may improve local control and survival.

CONCLUSIONS

The management of retroperitoneal sarcomas requires a multidisciplinary approach and is best accomplished at high-volume centers specializing in the care of patients with these complex malignancies. Current data suggest that radical resection remains the only chance for cure and that chemotherapy and radiation therapy may confer a survival benefit.