Pediatric retroperitoneal non-organ-originated malignancies: An analysis based on SEER database.

Retroperitoneal non-organ-originated malignancies are rare pediatric tumors with challenging diagnosis and treatment. The present study aimed to analyze the clinicopathological characteristics, treatment, and prognosis of retroperitoneal non-organ-originated malignancies. In the study, we included the pathological diagnosis of pediatric retroperitoneal non-organ-originated malignant tumors between 2000 to 2019 through the updated Surveillance, Epidemiology, and End Results database. We use the Kaplan-Meier survival curve to calculate the overall survival (OS) and cancer-specific survival (CSS). The risk of all-cause death and disease-specific death were analyzed using Cox proportional hazard regression model and Fine-and-Grey competitive hazard model, respectively. In the study, a total of 443 pediatric retroperitoneal non-organ-originated malignancies were included. Of them, only 22.3% of patients had no metastatic disease, 42.9% had distant metastasis and 34.8% had locally advanced diseases. The primary pathological tumor was neuroblastoma followed by germ cell tumor. The overall 10-year OS and CSS were 70.7% and 73.1%, respectively, and the 10-year OS and CSS of metastatic diseases were 54.4% and 56.6%, respectively. Older children, worse tumor stage at diagnosis, incomplete resection, and prolonged time from diagnosis to treatment were significantly associated with worse survival outcomes. Radiotherapy and chemotherapy did not significantly improve the prognosis of patients without complete tumor resection. The study indicated that most pediatric retroperitoneal non-organ-originated malignancies diagnosed with metastatic diseases have plagued treatment. Radiotherapy and chemotherapy are the main treatment methods for children unable to undergo complete surgical treatment. However, these treatments do not reach the same therapeutic effect as complete tumor resection after early diagnosis. Hence, early diagnosis and surgery for complete tumor resection are of utmost importance.

Practical Management of Adult Ultra-Rare Primary Retroperitoneal Soft Tissue Sarcoma: A Focus on Perivascular Epithelioid Tumours and Extraosseous Ewing Sarcoma.

With the exception of well-differentiated liposarcoma, dedifferentiated liposarcoma, leiomyosarcoma, solitary fibrous tumour, malignant peripheral nerve sheath tumour, and undifferentiated pleomorphic sarcoma, the majority of the ≈70 histologic subtypes of retroperitoneal sarcoma are defined as 'ultra-rare' sarcomas, with an incidence of ≤1-5/1,000,000 persons/year. For most of these ultra-rare RPS subtypes, diagnosis and treatment follows international guidelines for the management of more common RPS histologies, with en bloc surgical resection as the mainstay of curative treatment, and enrolment in clinical trials where possible. Because the treatment of RPS is heavily driven by histology, the surgeon must be familiar with specific issues related to the diagnosis and management of ultra-rare sarcoma subtypes. Expert radiological and surgeon reviews are required to differentiate similarly presenting tumours where surgery can be avoided (e.g., angiomyolipoma), or where upfront systemic therapy is indicated (e.g., extraosseous Ewing's sarcoma). Thus, the management of all retroperitoneal sarcomas should occur at a sarcoma referral centre, with a multidisciplinary team of experts dedicated to the surgical and medical management of these rare tumours. In this focused review, we highlight how diagnosis and management of the ultra-rare primary RPS histologies of malignant perivascular epithelioid cell tumour (PEComa), extraosseous Ewing sarcoma (EES), extraosseous osteosarcoma (EOS), and rhabdomyosarcoma (RMS) critically diverge from the management of more common RPS subtypes.

Primary retroperitoneal squamous cell carcinoma: a literature review.

PURPOSE: Retroperitoneal squamous cell carcinoma is an extremely rare histological variant of retroperitoneal tumors. The exact etiology and origin of the same is still unknown. To date, only a few case reports have been published in the literature. Due to rarity, standard treatment protocol is not available. The article aims to review the literature and treatment options available for this uncommon entity, based on available data. METHODS: We searched the databases like PubMed, PubMed Central, Scopus, and Google Scholar with the keywords "Squamous cell carcinoma" and "retroperitoneal tumors". Peer-reviewed and recent articles were screened. RESULTS: Seven relevant articles comprising 14 cases were found. Due to the small number of reports, tabulation of treatment details and outcome was done. Like the sarcoma variant, these tumors also present with a large mass in the abdomen and abdominal discomfort. Association with human papillomavirus appears to be the most common factor that gives rise to squamous histology. CONCLUSION: Retroperitoneal SCC is an uncommonly diagnosed entity. Although no specific treatment guidelines exist for this uncommon malignancy; surgery followed by adjuvant or definitive radiotherapy with concurrent chemotherapy (in inoperable cases) seems a feasible option. Multicentre trials should be conducted for establishing definitive treatment strategies for this ailment.

Large retroperitoneal extraskeletal Ewing's sarcoma with renal pedicle invasion: a case report.

BACKGROUND: Extraskeletal Ewing's sarcoma (EES) is a rare malignant tumor primarily found in children and young adults. Localized disease can present with nonspecific symptoms such as local mass, regional pain, and increased skin temperature. More severe cases may present with systemic symptoms such as malaise, weakness, fever, anemia, and weight loss. Among these lesions, retroperitoneal sarcomas are relatively uncommon and difficult to diagnose. Since they are usually asymptomatic until large enough to compress or invade the surrounding tissues, most are already advanced at first detection. Traditionally, the treatment of choice is complete surgical resection, sometimes combined with postoperative radiotherapy and chemotherapy. We report a case of EES with left renal artery invasion in the left retroperitoneal cavity successfully treated with transarterial embolization and surgery. CASE PRESENTATION: A 57-year-old woman with a negative family history of cancer presented at our Urology Department with a large left retroperitoneal tumor found by magnetic resonance imaging during the health exam. Physical examination showed a soft abdomen and no palpable mass or tenderness. Imaging studies showed that the tumor covered the entire left renal pedicle, but the left kidney, left adrenal gland, and pancreas appeared tumor free. Since the tumor tightly covered the entire renal pedicle, tumor excision with radical nephrectomy was advised. The patient underwent transarterial embolization of the left renal artery with 10 mg of Gelfoam pieces daily before surgical excision. Tumor excision and left radical nephrectomy were uneventful the day after embolization. Post-operatively, the patient recovered well and was discharged on day 10. The final histopathological analysis showed a round blue cell tumor consistent with an Ewing sarcoma, and the surgical margins were tumor free. CONCLUSIONS: Retroperitoneal malignancies are rare but usually severe conditions. Our case report showed that retroperitoneal EES with renal artery invasion could be treated safely with transarterial embolization and surgery.

New developments in the pathology and molecular biology of retroperitoneal sarcomas.

Retroperitoneal sarcomas (RPS) refer to a heterogeneous group of malignancies of mesenchymal origin developing from retroperitoneal tissues and vessels. The most frequent RPS are well differentiated/dedifferentiated liposarcomas and leiomyosarcomas, but other rare histological subtypes can be observed. Over the last decade, significant advances have been made in the pathological and molecular characterization of sarcomas. These advances have led to major changes in their diagnostic management as well as in the development of new therapeutic strategies based on tumor biology and microenvironment. This review describes the current knowledge and recent findings in the pathology and molecular biology of the most frequent RPS subtypes.

Current management of benign retroperitoneal tumors.

Benign retroperitoneal tumors (BRT) represent a rare group of heterogeneous diseases. The literature lacks high-quality evidence about the optimal management of BRT, and most of the information available takes the form of case reports or case series. The aim of this review is to provide an overview of current management strategies for adult patients with BRT. A literature search using PubMed indexed articles was conducted and BRT were classified into five different biological subgroups: 1) lipomatous tumors, 2) smooth muscle tumors, 3) peripheral nerve sheath tumors, 4) myofibroblastic tumors, and 5) others. Tumors that are primarily pelvic in origin were excluded. Despite the significant heterogeneity of the disease, several generic considerations have emerged and can be applied to the management of BRT. Specifically, the risk of misdiagnosing a BRT with another pathology such as retroperitoneal sarcoma is notable. When encountered, suspected BRT should therefore be referred to a specialized sarcoma center. Multidisciplinary tumor boards, present at these centers, have a pivotal role in managing BRT. The decision of whether to offer surgery, nonsurgical treatment or a "watch-and-wait" approach should be made after multidisciplinary discussion, depending on tumor histology. Moving forward, collaborative research efforts dedicated to BRT remain crucial in gathering evidence and knowledge to further optimize patient care.

Review of diagnosis, differential diagnosis, and management of retroperitoneal lymphangioma.

Lymphatic malformation (LM) is the currently preferred term for what was previously known as lymphangioma. Retroperitoneal LMs are extremely rare, benign, cystic masses that arise from lymphatic vessels. They can be challenging to diagnose because they resemble other retroperitoneal cystic tumors. The development of treatment strategies for rare diseases, including retroperitoneal LM, requires the acquisition of new knowledge to enhance our understanding of the disease progression. Therefore, we present an update regarding fundamental and advanced issues associated with retroperitoneal LM. This review describes the epidemiology, histopathology, biomedicine, clinical manifestations, radiological features, differential diagnosis, and management of this lesion.

Landmark Series: A Review of Landmark Studies in the Treatment of Primary Localized Retroperitoneal Sarcoma.

Primary localized retroperitoneal soft tissue sarcomas (RPS) have shorter survival than other soft tissue sarcoma sites owing to higher local recurrence rates associated with histologic types most commonly found in this location, large tumor size at diagnosis (median 20 cm), and anatomical constraints of surgery in the retroperitoneum. The only curative treatment for RPS has traditionally been complete macroscopic en bloc resection with adjacent structures that cannot be surgically separated from the tumor. Compartmental resection, incorporating adjacent organs and soft tissues en bloc, even without overt infiltration at the time of surgery, performed in sarcoma referral centers may reduce local recurrence rates. Preoperative radiotherapy has not been shown to reduce early 3-year local recurrences in a phase III, international, randomized, controlled trial (STRASS). Longer follow-up is needed to determine whether well-differentiated and low-grade dedifferentiated liposarcoma prone to late local recurrences may benefit. Currently, there is no level 1 evidence to support the use of perioperative systemic therapy. Observational studies suggest that patients with high-grade histologies and borderline resectable RPS may benefit. A phase III, international, randomized, controlled trial (STRASS2) is currently evaluating a histology-tailored chemotherapy regimen for patients with leiomyosarcoma and dedifferentiated liposarcoma at high risk of distant metastatic recurrence. Novel biomarkers can help determine prognosis and more accurately predict response to treatment, but more research is needed to translate these discoveries into therapeutic benefits. Refined molecular data for histological types will allow personalized surgery, radiotherapy, and systemic therapy with lower toxicity and improved survival in the future.

Transferability of Health-Related Quality of Life Data of Large Observational Studies to Clinical Practice: Comparing Retroperitoneal Sarcoma Patients from the PROSa Study to a TARPS-WG Cohort.

INTRODUCTION: Health-related quality of life (HRQoL) is crucial for shared decision-making. The "Patient-Reported Outcome measures in Sarcoma" (PROSa) study evaluated HRQoL in general. We evaluated the transferability of PROSa data to clinical practice for the subgroup of retroperitoneal sarcoma (RPS). METHODS: To obtain a PROSa-RPS cohort, we excluded patients with bone sarcomas and gastrointestinal stromal tumors from the complete PROSa cohort (n = 1,113), limited tumor localization to trunk and retroperitoneum, and excluded patients with metastases. We evaluated the HRQoL data of the resulting 76 patients and compared their clinical data to those of the Transatlantic Autralasian Retroperitoneal Sarcoma Working Group (TARPS-WG, n = 1,007). RESULTS: Confidence intervals for patient sex, histological subtype (LPS vs. non-LPS), grading (G1 vs. G2/3), surgical margins (R2 vs. no R2), and perioperative chemo- and radiotherapy (yes vs. no) were overlapping in both cohorts. EORTC QLQ-C30 from RPS-PROSa patients demonstrated that two-thirds had clinically relevant restrictions in physical functioning. Two-thirds reported dyspnea, followed by fatigue and pain. CONCLUSION: Clinical data from RPS-PROSa patients are comparable to those of an RPS reference cohort from expert centers. We believe that HRQoL data of RPS patients extracted from PROSa are transferable to clinical practice.

Adjuvant therapy for retroperitoneal sarcoma: a meta-analysis.

BACKGROUND: Adjuvant therapy is a promising treatment to improve the prognosis of cancer patients, however, the evidence base driving recommendations for adjuvant radiotherapy (ART) or chemotherapy (ACT) in retroperitoneal sarcomas (RPS) primarily hinges on observational data. The aim of this study was to evaluate the effectiveness of adjuvant therapy in the management of RPS patients. METHODS: We searched PubMed, Web of Science, Embase, ASCO Abstracts, and Cochrane Library for comparative studies (until December 2020) of adjuvant therapy versus surgery alone. Data on the following endpoints were evaluated: overall survival (OS), local recurrence (LR), recurrence-free survival (RFS), and metastasis-free survival (MFS). Data were summarized as hazard ratios (HR) with 95% confidence intervals (CI). Risk of bias of studies was assessed with Begg's and Egger's tests. RESULTS: A total of 15 trials were eligible, including 9281 adjuvant therapy and 21,583 surgery alone cases (20 studies for OS, six studies for RFS, two studies for LR, and two studies for MFS). Meta-analysis showed that ART was associated with distinct advantages as compared to surgery alone, including a longer OS (HR = 0.80, P < 0.0001), a longer RFS (HR = 0.61, P = 0.0002), and a lower LR (HR = 0.31, P = 0.005). However, this meta-analysis failed to demonstrate a benefit of ACT for RPS patients, including OS (HR = 1.11, P = 0.19), RFS (HR = 1.30, P = 0.09) and MFS (HR = 0.69, P = 0.09). In the sensitivity analysis, ACT was associated with a worse OS (HR = 1.19, P = 0.0002). No evidence of publication bias was observed. CONCLUSIONS: Overall, the quality of the evidence was moderate for most outcomes. The evidence supports that ART achieved a generally better outcome as compared to surgery alone.

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.

Retroperitoneal sarcoma: the Transatlantic Australasian Retroperitoneal Sarcoma Working Group Program.

PURPOSE OF REVIEW: The Transatlantic Australasian Retroperitoneal Sarcoma Working Group (TARPSWG) is a bottom-up clinical network established in 2013 with the goal of improving the care and outcomes of patients with retroperitoneal sarcoma (RPS). Here, we review the knowledge produced by this collaborative effort and examine the future potential of this group. RECENT FINDINGS: TARPSWG has produced retrospective studies focused on patients with primary and recurrent RPS allowing a better understanding of patient prognosis, treatment outcomes and tumor biology. The group has played a pivotal role in a phase III randomized STudy of preoperative RAdiotherapy plus Surgery versus surgery alone for patients with Retroperitoneal Sarcoma (STRASS) trial, favoring patient recruitment and trial completion. A prospective registry for patients with primary RPS populated by TARPSWG members is ongoing. TARPSWG has created consensus papers with recommendations regarding the management of patients with primary, recurrent and metastatic RPS that collated the views of representatives of sarcoma centers from Europe, North America, Asia and Australia. SUMMARY: Since its inception, TARPSWG has become a leading network in the field of RPS. It has made a major contribution to the world of RPS research and cares allowing to overcome the limitations related to the rarity of the disease through collaboration.

Retroperitoneal extension of massive ulcerated testicular seminoma through the inguinal canal: A case report.

INTRODUCTION: Testicular cancers represent about 5% of all urological malignancies and 1-1.5% of all male neoplasms. Most of the testicular cancers are localized (68%) at diagnosis. Bulky masses in the scrotum are rare. We present a rare case of bulky testicular cancer with retroperitoneal spread through the inguinal canal. CASE REPORT: A 44-year-old man came to the emergency department referring weakness and the presence of a scrotal mass. At physical examination, a voluminous mass was found, with necrotic phenomena within the scrotum. Abdomen was tense and sore. Abdominal CT scan revealed a bulky testicular mass spreading to the retroperitoneal space through the inguinal canal with node enlargement. Patient underwent orchiectomy with excision of infiltrated scrotum skin. Histologic diagnosis confirmed a typical form seminoma. The patient was then treated with a cisplatin-based chemotherapy, with a partial response. The patient recently relapsed and he is being treated with a new line of chemotherapy and subsequent surgery with or without radiotherapy. CONCLUSIONS: We described a rare presentation of testicular cancer. This case highlights the importance of a multidisciplinary approach to rare testis tumour presentation and early diagnosis for testicular cancers.

Diagnostic and management challenges for MDM2-, CDK4-negative fatty tumors of the retroperitoneum.

BACKGROUND: Neoplasms of the retroperitoneum that contain a major fat component may represent either benign entities, such as lipomas or angiomyolipomas, or malignancy such as liposarcoma. Distinguishing these diagnoses has important implications for management. While liposarcomas often stain positively for MDM2 and CDK4 proteins, absence of these markers can lead to diagnostic and management challenges. METHODS: We examined three cases in our institution of fat-containing masses of the retroperitoneum that lacked MDM2 and CDK4 markers to highlight the challenges in diagnosing and managing these cases. A thorough review of the literature examining radiologic and histologic features that can be used to determine that diagnosis was conducted and summarized. RESULTS: The three cases we present represent the three main diagnostic entities that can be found in among fatty tumors of the retroperitoneum: lipoma, angiomyolipoma, and liposarcoma. While radiologic features and analysis of histology helped to inform management, these cases in conjunction with the literature also illustrate the limitations of the diagnostic work up and importance also factoring the biologic behavior of the tumor in its management. CONCLUSION: Fat-containing tumors of the retroperitoneum that do not stain for MDM2 or CDK4 can pose a diagnostic challenge. Assessing radiologic and pathologic features in conjunction with the biologic behavior of these tumors should inform their management.

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.

SEOM Clinical Guideline of management of soft-tissue sarcoma (2020).

Soft-tissue sarcomas constitute an uncommon and heterogeneous group of tumors of mesenchymal origin. Diagnosis, treatment, and management should be performed by an expert multidisciplinary team. MRI/CT of the primary tumor and biopsy is mandatory before any treatment. Wide surgical resection with tumor-free tissue margin is the mainstay for localized disease. Radiotherapy is indicated in large, deep, high-grade tumors, or after marginal resection not suitable for re-excision. Perioperative chemotherapy should be discussed for high-risk sarcomas of the extremities and trunk-wall. In the case of oligometastatic disease, patients should be considered for local therapies. First-line treatment with anthracyclines (or in combination with ifosfamide) is the treatment of choice. Other drugs have shown activity in second-line therapy and in specific histological subtypes but options are limited and thus, a clinical trial should always be discussed.

[French ccAFU guidelines - update 2020-2022: retroperitoneal sarcoma]. / Recommandations françaises du Comité de cancérologie de l'AFU - actualisation 2020-2022 : sarcomes rétropéritonéaux.

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.