UNASSIGNED: Liposarcoma is a malignant tumor that originates from adipose tissue and can occur in any part of the body. There is currently no clear conclusion on whether there are significant differences in prognosis between liposarcoma at different anatomical locations, especially retroperitoneal liposarcoma (RLPS) and non retroperitoneal liposarcoma (NRLPS). The aim of this study is to reveal whether there are differences in prognosis between these two locations of liposarcoma, and further explore the fundamental reasons behind these differences.
UNASSIGNED: We conducted an in-depth investigation into the factors affecting the prognosis of patients with liposarcoma by analyzing the data from the Surveillance, Epidemiology, and End Results Program (SEER) database. Then, we used propensity score matching (PSM) to balance these prognostic factors for comparative analysis of survival between RLPS and NRLPS. In addition, by analyzing transcriptome and whole exome data from TCGA and the Japan Genotypic Phenotype Archive (JGA), we identified genes with significant expression differences and explored changes in the immune microenvironment.
UNASSIGNED: Through analysis of RLPS and NRLPS patients in the SEER database, we observed significant prognostic differences between the two groups, with RLPS exhibiting worse prognosis (p < 0.001). Even after adjusting for confounding factors through PSM, these survival rate differences remained significant, with RLPS still showing worse prognosis (p = 0.017). Furthermore, our analysis of transcriptomic data led to the identification of 467 differentially expressed genes. Additionally, we noted significant differences in the immune microenvironment and whole exome sequencing data between the two groups.
UNASSIGNED: There are significant differences between patients with RLPS and NRLPS. Therefore, from clinical research to treatment strategies, RLPS and NRLPS should be considered as two distinct types of tumors, necessitating differentiated approaches for their study and treatment.

UNASSIGNED: Retroperitoneal lymphatic malformations (LMs) are rare. Currently, the treatment of retroperitoneal LMs remains challenging. This study aimed to examine the safety and efficacy of laparoscopic-assisted sclerotherapy for retroperitoneal LMs in pediatric patients.
UNASSIGNED: We retrospectively reviewed patients treated with laparoscopic-assisted sclerotherapy for retroperitoneal LMs in a single tertiary medical center between July 2020 and February 2023. Doxycycline was prepared into a solution with a concentration of 10 mg/ml for use in sclerotherapy. Demographic data, clinical features, details of management, and outcomes were collected and analyzed.
UNASSIGNED: A total of six patients, comprising three males and three females, were identified. The LMs were categorized into four macrocystic and two mixed-cystic types. The mean age and weight were 52.2 months (range, 11-108 months) and 20 kg (range, 12.5-27.5 kg), respectively. Three patients presented with abdominal pain or distension, while the other three patients were asymptomatic. All six patients underwent a total of eight sclerotherapy sessions. Two patients experienced intra-cystic hemorrhage and required a second sclerotherapy session. Only one patient presented with vomiting after sclerotherapy, which resolved spontaneously. Five patients met the complete response criteria, and one patient met the effective criteria. The mean reduction in lesion size was 92.3% (range, 69.9%-99.6%). No further complications or recurrence were recorded during follow-up.
UNASSIGNED: Laparoscopic-assisted sclerotherapy is a safe and effective approach for treating retroperitoneal LMs. This technique is applicable for both macrocystic and mixed-cystic retroperitoneal LMs.

BACKGROUND: Schwannomas are benign usually encapsulated nerve sheath tumors derived from the Schwann cells, and affecting single or multiple nerves. The tumors commonly arise from the cranial nerves as acoustic neurinomas but they are extremely rare in the pelvis and the retroperitoneal area. Retroperitoneal pelvic schwannomas often present with non-specific symptoms leading to misdiagnosis and prolonged morbidity.
METHODS: We report the case of a 59-year-old woman presenting with a feeling of heaviness in the lower abdomen who was found to have a retroperitoneal pelvic schwannoma originating from the right femoral nerve. She had a history of two resections of peripheral schwannomas at four different sites of limbs. After conducting magnetic resonance imaging, this pelvic schwannoma was misdiagnosed as a gynecological malignancy. The tumor was successfully removed by laparoscopic surgery. Pathological analysis of the mass revealed a benign schwannoma of the femoral nerve sheath with demonstrating strong, diffuse positivity for S-100 protein.
CONCLUSIONS: Although retroperitoneal pelvic schwannoma is rare, it should be considered in the differential diagnosis of pelvic masses, especially in patients with a history of neurogenic mass or the presence of neurogenic mass elsewhere.

OBJECTIVE: Reducing operative injuries is important in living donor nephrectomy. The robot-assisted transperitoneal approach has some advantages than traditional laparoscopic techniques. However, longer operation time and risks of abdominal complications indicate the need for improved techniques. The aim of this study is to present the robot-assisted laparoscopic retroperitoneal donor nephrectomy and evaluate its safety and feasibility.
METHODS: This was a retrospective study. From June 2016 to December 2020, 218 living donors underwent robot-assisted laparoscopic retroperitoneal donor nephrectomy. Perioperative data such as operation time, warm ischemia time, length of stay and complications were collected and analyzed. To evaluate the feasibility of this surgical technique, the cumulative summation method was used to construct a learning curve.
RESULTS: There were 60 male and 158 female donors aged 36-72 years, with an average age of 53.1 ± 6.8 years. Three patients (1.4%) were converted to open surgery. The mean operation time was 115.4 ± 41.9 min, the warm ischemia time was 206.6 ± 146.7 s, and the length of stay was 4.1 ± 1.4 days. Complications were reported in 22 patients (10.1%), three of whom (1.4%) had Clavien‒Dindo IIIa complications. No ileus occurred. No donors were readmitted. Four patients had delayed graft function. The cumulative summation curve showed that the number needed to reach proficiency was 33. The operation time and warm ischemia time after technical proficiency were 100.4 ± 21.6 min and 142.5 ± 50.7 s, respectively.
CONCLUSIONS: Robot-assisted laparoscopic retroperitoneal donor nephrectomy is a safe and efficient technique that offers advantages of shorter operation time and no abdominal organ interference.

BACKGROUND: Retroperitoneal partial nephrectomy (RLPN) is the premier treatment for localized renal tumors despite narrow operation space. Many efforts have been taken to facilitate the operation of RLPN, but the optimal resolution remains debatable.
OBJECTIVE: To explore the feasibility of using Mini-lap to improve workspace and surgical vision in RLPN.
METHODS: A multicenter retrospective review of 51 patients who underwent RLPN with Mini-lap from January 2018 to December 2020 was conducted.
METHODS: Standard RLPN under three poles was performed in all cases. We highlighted the usage of Mini-lap (Teleflex Minilap percutaneous Surgical System) as a novel retractor in RLPN.
UNASSIGNED: Demographics, preoperative, intraoperative, and postoperative outcomes were assessed.
CONCLUSIONS: All 51 cases completed RLPN with three ports successfully and no conversion to open surgery. The mean diameter of tumors was (3.53 ± 1.05) cm, in which 62.7% (32/51) were located anteriorly. The operation time and warm ischemic time (WIT) were (86.7 ± 15.9) min and (25.6 ± 5) min respectively. Minor complications (Clavien grade 1-2) occurred in 6 cases. The limitations were small sample size, retrospective design, and absence of control.
CONCLUSIONS: Mini-lap could be used as a mini-retractor in RLPN, sparing extra assistant ports, expanding workspace, and optimizing vision.
RESULTS: With highlights of larger workspace and less instrument interference, mini-lap could be applied in retroperitoneal laparoscopic partial nephrectomy.

Castleman disease (CD), a distinct lymphoproliferative disorder, is infrequently encountered in clinical practice and poses significant diagnostic challenges. We present the case of a 48-year-old asymptomatic female, admitted for evaluation of a hepatic mass detected in the liver\'s right lobe. Preoperative laboratory tests were within normal limits. Diagnostic imaging, including contrast-enhanced magnetic resonance imaging (MRI), was suggestive of hepatocellular carcinoma. Furthermore, contrast-enhanced abdominal computed tomography (CT) scans were indicative of hepatic malignancy. Subsequently, the patient underwent laparoscopic surgery targeting a retroperitoneal mass. During the surgical procedure, it was observed that the tumor was a retroperitoneal mass situated posterior to the liver, exhibiting localized adhesion to hepatic tissue. The postoperative histopathological analysis revealed the mass to be hyaline-vascular type Castleman disease (HV-CD), thereby refuting the initial diagnosis of a hepatic malignancy. This case underscores the complexity of diagnosing retroperitoneal Castleman disease, particularly when it masquerades as a hepatic tumor.

Fat-forming solitary fibrous tumor is a rare and specific subtype of solitary fibrous tumor. In this case, a mass of 8.3 cm in diameter was found in a 59-year-old male patient\'s right retroperitoneum, as revealed by abdominal contrast-enhanced computed tomography (CT) images. The tumor exhibited a well-circumscribed nature and histological features characterized by a combination of hemangiopericytomatous vasculature and mature adipose tissue, comprising around 70% of the total tumor composition. Immunohistochemistry staining revealed diffuse positive expression of STAT6 and CD34 in the tumor cells. Based on these findings, the final diagnosis was determined to be a fat-forming solitary fibrous tumor located in the retroperitoneum. It is important to consider other potential differential diagnoses, including angiomyolipoma, dedifferentiated liposarcoma, spindle cell lipoma, and atypical lipomatous tumor/well-differentiated liposarcoma.

Small round cell undifferentiated sarcoma is a rare and highly invasive group of malignant bone and soft tissue tumors, often associated with a high misdiagnosis rate. The patient in this case was a 34-year-old male who presented with a two-month history of abdominal pain that worsened over the past two weeks. Elevated levels of tumor markers CA19-9 and CA72-4 were observed. Imaging revealed a substantial, well-vascularized mass in the lower left abdomen, located in the posterior abdominal cavity, invading the descending colon and the root of the small mesentery, and infiltrating the serous layer. The lesion was extensively resected without any postoperative complications. Microscopic examination indicated a combination of mucinous adenocarcinoma (approximately 30%) and small round cell undifferentiated sarcoma (approximately 70%). The patient was followed up for six months, and one month after surgery, a recurrence of the tumor was observed in the left paracolonic sulcus area, with metastases to the abdominal wall, peritoneum, and medial iliac muscles. Chemotherapy and targeted therapy were administered, and the patient currently survives with the presence of tumors. Small round cell undifferentiated sarcoma is an uncommon and highly invasive tumor, and clinical surgeons need to raise their awareness and realize to the maximum extent possible that this disease can be described through a multi-modal combination of immunohistochemistry and genetic test to improve diagnostic accuracy and reduce missed diagnoses. Further research in the field of biology is necessary to explore targeted drugs specifically suitable for this disease.

UNASSIGNED: Anastomotic hemangioma is a rare subtype of capillary hemangioma primarily found in the genitourinary tract. We present a case of a patient with an anastomotic hemangioma located in the retroperitoneal space; then, we explore and summarize the imaging features from previously reported cases for accurate diagnosis.
UNASSIGNED: A 57-year-old woman complained of left lower back pain. Contrast-enhanced ultrasound revealed a hypoechoic mass with \"slow-in and slow-out\" enhancement. Abdominal CT scan displayed a well-defined, round soft tissue mass in the right retroperitoneal region with obvious enhancement. MRI indicated low signal on T1-weighted imaging, high signal on T2-weighted imaging and diffusion-weighted imaging, and progressive enhancement after enhancement. Surgical removal of the tumor was performed. Histopathological examination exhibited a distinct tumor border with interconnected blood vessels and a cavity lined by a single layer of cubic endothelial cells. Immunohistochemistry confirmed the presence of CD31[+] and CD34[+]. The final pathological diagnosis was anastomotic hemangioma. No recurrence was observed during a 40-month follow-up.
UNASSIGNED: Retroperitoneal anastomotic hemangioma is a rare and benign neoplasm that may be misdiagnosed as ectopic pheochromocytoma or angiosarcoma. This case report presents and analyzes the imaging characteristics of a series of retroperitoneal anastomotic hemangiomas, which can be valuable for future diagnoses and help prevent unnecessary surgeries.

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