Retroperitoneal liposarcoma during pregnancy is rare and poses significant diagnostic challenges, even for experienced specialists. We present a case report of a 27-year-old female patient, 15 weeks pregnant, who was admitted to the hospital due to a massive retroperitoneal liposarcoma. The patient underwent surgical resection of the tumor. Postoperative pathology confirmed a diagnosis of well-differentiated liposarcoma. Although liposarcoma during pregnancy is rare and challenging to diagnose, CT or MRI plays a crucial role in its detection. The recurrence rate depends on the pathological stage, histological grade, and ability to resect the tumor.

OBJECTIVE: To assess risk factors of retroperitoneal and lower extremity musculoskeletal bleed in acquired haemophilia (AHA) and perform an objective assessment of disability and influence on survival.
METHODS: We included 49 patients with AHA from November 2017 to May 2023. The occurrence of any retroperitoneal or/and lower extremities bleeding manifestation was investigated. On clinical follow-up, we search for compressive femoral neuropathy and quadriceps amyotrophy. The lower extremity functional scale (LEFS) was carried out one year after the last bleeding event in all AHA patients.
RESULTS: A 61.2% of patients in our AHA cohort presented with any retroperitoneal and/or lower extremities musculoskeletal manifestation. Those patients had higher percentage of major bleeding EACH2/ISTH criteria (90% vs. 57%, p = .01), needs of blood transfusions (86% vs. 57% of patients, p = .03), and haemostatic by-pass products (90% vs. 63%, p = .02). Hypertension (HR 2.6, 95% CI 1.1-5.9, p = .02), presence of autoimmune disease (HR 13, 95% CI 1.7-99, p = .01), and inhibitor level > 20 BU (HR 2.6 95% CI 1.0-6.8, p = .04) significantly predicted retroperitoneal/lower extremities clinical manifestations. Most frequent sequelae were quad atrophy (30.6%) and femoral nerve palsy (20.4%). Quad atrophy and LEFS scores under 50 were associated with increased mortality (HR 3, 95% CI 1.1-8.6 and HR 12, 95% CI 3.3-45, respectively).
CONCLUSIONS: AHA with retroperitoneal/lower extremities bleeding involvement is of greater severity and shows high disability and worst survival outcomes. Quadriceps atrophy and LEFS scale scoring under 50 predicted mortality in our AHA patients.

Tumors originating from soft tissues are uncommon, among these tumors, liposarcomas are the most frequent. These tumors remain asymptomatic for a long time, and only revealing themselves when they reach an important size. In such cases, treatment is difficult, requiring extensive surgery procedures that can excise several adjacent structures, potentially completed by adjuvant radiotherapy. Despite successful treatment, the recurrence rate remains very high. We report the case of a giant liposarcoma requiring a monobloc extensive resection involving the removal of the tumor, left kidney, left adrenal gland, and a portion of the posterior abdominal wall.

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.

UNASSIGNED: There is an unmet need to avoid long-term morbidity associated with standard cytotoxic treatment for low-volume metastatic seminoma. Our aim was to assess the oncological efficacy and surgical safety of retroperitoneal lymph node dissection (RPLND) as treatment in a population-based cohort of metastatic seminoma patients with limited retroperitoneal lymphadenopathy.
UNASSIGNED: Sixty-two seminoma patients in Norway and Sweden were included in the cohort from 2019 to 2022. Patients with lymphadenopathy ≤3 cm, having primary clinical stage (CS) IIA/B or CS I with a relapse, were operated with uni- or bilateral template RPLND, open or robot assisted. The outcome measures included surgical complications as per Clavien-Dindo, and Kaplan-Meier survival estimates for 24-mo progression-free survival (PFS) and overall survival (OS).
UNASSIGNED: In the cohort, 33 (53%) had CS I with a relapse during surveillance, six (10%) CS I with a relapse following adjuvant chemotherapy, and 23 (37%) initial CS IIA/B. Metastatic seminoma was verified in 58 patients (94%) with a median largest diameter of 18 mm (interquartile range [IQR] 13-24). Robot-assisted RPLND was performed in 40 patients (65%). Clavien-Dindo III complications were observed in three patients (5%); no grade ≥IV complications occurred. Eighteen patients (29%) received adjuvant chemotherapy after surgery. The median follow-up was 23 mo (IQR 16-30), and recurrence occurred in six patients (10%) after a median of 8 mo (IQR 4-14). PFS was 90% (95% confidence interval: 0.86-1) and OS was 100% at 24 mo.
UNASSIGNED: RPLND as primary treatment is an option for selected low-stage seminomas with a limited burden of disease, showing low complications and low relapse rates, with the potential to reduce long-term morbidity.
UNASSIGNED: In seminoma patients with limited metastatic spread, surgery is a treatment option offering an alternative to chemotherapy or radiation. This paper covers the first 62 patients operated in Norway and Sweden.

UNASSIGNED: Small tumors may be difficult to identify visually and require preoperative effort to locate. Recent advancements in mixed reality technology have improved surgical accuracy in various departments. Here, we present the application of mixed reality-assisted surgery and a guiding marker in the case of small retroperitoneal metastasis of uterine cancer.
UNASSIGNED: A 67-year-old female with a history of uterine cancer had a retroperitoneal metastasis in the lateroconal fascia near the right diaphragm, measuring 2 cm and infiltrating the peritoneum. We performed precise surgical planning using the preoperative mixed reality software \"Holoeyes\" on a head-mounted display called HoloLens2. Novel techniques, including ultrasonography-guided placement of a guiding marker and strategic port-site placement facilitated by HoloLens2, ensured accurate tumor identification and laparoscopic resection with minimal blood loss and no intraoperative complications.
UNASSIGNED: The use of mixed reality-assisted surgery and a guiding marker effectively enhanced the precision of retroperitoneal tumor resection.

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: Single-Port Robot-Assisted Partial Nephrectomy (SP-RAPN) can be performed by transperitoneal and retroperitoneal approaches. However, there is a lack of surgical outcomes for novel Retroperitoneal Low Anterior Access (LAA) in SP-RAPN. The study compared outcomes of the standard approach (SA), considering transperitoneal (TP) and posterior retroperitoneal (RP) access vs LAA in SP-RAPN series.
METHODS: 102 consecutive patients underwent SP-RAPN between 2019 and 2023 at a tertiary referral robotic center were identified. Baseline characteristics, peri- and post-operative outcomes were collected. Patients were stratified according to surgical approach into standard (RP or TP) vs LAA and, subsequently, RP vs LAA. Multivariable logistic regression analysis was used to test the probability of the same-day discharge adjusting for comorbidity indexes.
RESULTS: Overall, 102 consecutive patients were included in this study (68 SA - 26 TP and 42 posterior RP vs 34 LAA). Median age was 60 (IQR 51.5-66) years and median BMI was 31 (IQR 26.3-37.6). No baseline differences were observed. LAA exhibited significantly shorter length of stay (LOS) (median 10 [IQR 8-12] vs 24 [IQR 12-30.2.] hours, p < .0001), reduced post-operative pain (p < .0001) and decreased narcotic use on 0-1 PO Day (p < .001) compared to SA and RP only. Multivariate analysis, adjusting for comorbidities, identified LAA as a strong predictor for Same-Day Discharge.
CONCLUSIONS: LAA is an effective approach as well as RP and TP, regardless of the renal mass location, whether it is anterior or posterior, upper/mid or lower pole, yielding favorable outcomes in LOS, post-operative pain and decreased narcotics use compared to SA in SP-RAPN.

OBJECTIVE: There is limited evidence regarding the systemic treatment of retroperitoneal soft-tissue sarcoma, and the current Japanese guidelines fail to make definitive suggestions. Here, we report our experience with combination chemotherapy of mesna, doxorubicin, ifosfamide, and dacarbazine (MAID) in this population.
METHODS: We retrospectively reviewed the records of eight patients (three male and five female) who received MAID for pathologically diagnosed metastatic unresectable retroperitoneal sarcoma (either leiomyosarcoma or pleomorphic sarcoma) between October 2019 and January 2022. Treatment efficacy, tolerability (need for dose reduction), and safety profiles were evaluated and summarized.
RESULTS: At initiation, the median age was 56.0 years, and the body mass index was 20.0 kg/cm2 Six patients had Eastern Cooperative Oncology Group performance status scores of 0. The net clinical benefit was a partial response in three (37.5%) patients, stable disease in four (50.0%), and progressive disease in one (12.5%). During the median 90.8 weeks of follow-up, disease in five patients progressed, resulting in a median progression-free survival of 48.4 weeks, and five deaths occurred, resulting in an overall survival of 95.1 weeks. Commonly observed adverse events were neutropenia (eight patients), anemia (eight patients), and decreased platelet count (seven patients), which led to dose reduction (60-80%) in six patients.
CONCLUSIONS: MAID combination therapy may be an acceptable option for advanced retroperitoneal sarcoma; however, its benefits must be carefully assessed owing to its not insignificant toxicity.

Myoepithelial carcinoma (MC) arises from the myoepithelial cells. It is a rare tumor with a predilection for salivary glands. MC in soft tissue is uncommon. Soft tissue MC exhibits dual epithelial and smooth muscle phenotype. The extremities and limb girdles are commonly affected. We present cytological findings of retroperitoneal MC with an accurate diagnosis being rendered with the aid of immunocytochemistry on the cell block and demonstration of EWSR1 rearrangements by fluorescence in situ hybridization on cytology smear. The smears were cellular, showing loose clusters and sheets of tumor cells embedded in dense eosinophilic to myxoid matrix material. The cells were oval to polygonal, with focal areas showing moderate nuclear pleomorphism, vesicular to coarse chromatin, and vacuolated cytoplasm with clearing. On immunocytochemistry, tumor cells were positive for epithelial membrane antigen, pan-cytokeratin, calponin, smooth muscle actin, and S-100. A literature review shows only a handful of cases of soft tissue MC. The current report emphasizes the need for cytomorphological awareness with the employment of ancillary testing for accurately diagnosing this rare tumor at an uncommon location. We also discuss the diagnostic challenges and troubleshooting.