One-Stage Surgical Resection and Functional Reconstruction for Upper Limb Soft Tissue Sarcoma.

BACKGROUND: Currently, the gold standard of treatment for extremity soft tissue sarcoma (STS) is limb-sparing surgery. When the upper extremity is involved, the functional outcome is frequently poor. A 1-step resection and functional reconstruction would be advisable to obtain a fast recovery. Our study aims at retrospectively analyzing our case series of immediate nerves and tendons reconstructions of the upper limb after STS resection, while combining a review of the literature. METHODS: A retrospective review was conducted on a consecutive series of patients who underwent an immediate functional reconstruction after STS resection of the upper limb between 2015 and 2022 among the IRCCS Foundation "Istituto Nazionale dei Tumori." The Disabilities of the Arm, Shoulder and Hand (DASH) score was considered the primary outcome. The obtained DASH scores were compared through groups that underwent different reconstructive procedures. The literature review was conducted according to the PRISMA (Preferred Reporting Items for Systematic review and Meta-Analysis) criteria among 3 databases (PubMed, EMBASE, and Cochrane) using the search parameters "(((upper extremity) OR (upper limb)) AND (functional reconstruction) AND (soft tissue sarcoma)." RESULTS: Between 2015 and 2022, 52 patients required a functional reconstruction. The mean follow-up time was 49.63 months. The DASH score analysis reported a mean value of 44.1 ± 26.7. A statistically significant difference was found between groups who underwent different reconstruction techniques, whereas no difference was found regarding exposure to neoadjuvant radiation therapy. The literature review reported few articles focusing on immediate functional reconstruction after STS resection, and only 6 articles were included in the review. CONCLUSIONS: Our review aimed at reporting our case series of immediate functional reconstructions after STS of the upper extremity, which is currently the most substantial one reported in literature to set an effective baseline for further studies in the field.

Visceral fat area and subcutaneous fat area as measures of body composition in soft tissue sarcoma.

BACKGROUND AND OBJECTIVES: Soft tissue sarcomas (STS) are a heterogenous group of malignancies of mesenchymal origin. Given recent data linking obesity as well as the pattern of fat distribution with cancer outcomes, we sought to investigate the association of visceral fat area (VFA) and subcutaneous fat area (SFA) with oncologic outcomes in patients with STS undergoing surgery. METHODS: We analyzed data from 88 patients with STS diagnosed from 2008 to 2022. Predictor variables included body mass index (BMI), VFA, and SFA. VFA and SFA were obtained from computed tomography of the abdomen and pelvis. Univariable and multivariable Cox regression analysis was used to analyze associations between predictor variables and overall survival and recurrence-free survival. RESULTS: Although BMI was closely correlated with VFA (r = 0.69, p < 0.0001) and SFA (r = 0.80, p < 0.0001), there was no significant association between high BMI, VFA or SFA, and worse oncologic outcomes. CONCLUSIONS: Although VFA and SFA are strongly correlated with BMI, we did not observe BMI nor imaging metrics of fat composition to be associated with worse oncologic outcomes. Further research is needed to elucidate any links between body fat content and metabolic or immune factors governing oncologic outcomes in STS.

Real-world Referral Pattern of Unplanned Excision in Patients With Soft-tissue Sarcoma: A Multicenter Study Conducted by the Bone and Soft-tissue Tumor Study Group of the Japan Clinical Oncology Group.

BACKGROUND/AIM: Despite the well-publicized clinical outcomes after unplanned excision (UE) and re-excision (re-excision) in patients with soft-tissue sarcoma (STS), there is little information about the real-life referral patterns for UE, such as patient profile, details of procedures, and subsequent management after UE. We aimed to investigate the characteristics of patients with UE who were referred to sarcoma-specific centers. PATIENTS AND METHODS: Between May 2022 and June 2023, we registered 97 patients who underwent UE and were referred to sarcoma-specific centers in Japan. We excluded those with well-differentiated liposarcomas and dermatofibrosarcoma protuberances. We investigated the details of UE and additional treatment after UE. RESULTS: There were 49 men and 48 women, with a mean age of 62 years. A broad range of surgeons performed UE; 36 plastic surgeons, 22 orthopedic surgeons, 17 general surgeons, 17 dermatologists, and 5 others. The mean tumor size was 4.1 cm. Local anesthesia was administered to 58 patients. Forty-five patients underwent UE without prior magnetic resonance imaging. Inappropriate transverse skin incisions were performed in 42 patients. Of the 97 patients, 82 underwent re-excision after UE. The mean time between UE and date of initial presentation at the referral hospital was 46 days. The mean interval between UE and re-excision was 96 days. Of the 82 patients, 59 underwent soft-tissue reconstruction after re-excision. CONCLUSION: A broad range of surgeons performed UE. Continuous education about STS should be considered for all surgeons. UE should be avoided because residual tumors are common, and reconstructive surgery may be necessary.

Retroperitoneal soft tissue sarcomas: Predictive factors for incomplete resection.

INTRODUCTION: Curative management of retroperitoneal sarcoma relies on surgery, and complete monoblock resection is one of the main prognostic factors. The goal of this study was to search predictive factors for incomplete resection. METHODS: All patients undergoing surgery for retroperitoneal sarcoma in two University hospitals between 2010 and 202 were included. The main endpoint was incomplete resection (R1 ad R2) after surgery. Secondary analysis was performed where marginal R0 resection was considered as complete. Univariate and multivariable analysis of demographics, radiological, surgical and pathologic criteria were performed. Overall survival, local and distant recurrence were evaluated. RESULTS: Fifty-eight patients were included in the study. Fifty patients had incomplete resection, of which seven had marginal R0 resection. In multivariable analysis, none of the factors analyzed were associated with incomplete resection. In secondary analysis, undifferentiated liposarcoma histology (OR 12.3, 95% CI [1.416-107.303], P=0.023) was statistically significantly associated with incomplete resection. Low grade (grade I) histology was predictive of complete resection (OR 0.24, 95% CI [0.060-0.959], P=0.043). Median follow-up duration was 27 months. Local and distant recurrence rates at three years were 37% and 22.4%, respectively. CONCLUSION: In this study, we highlighted several predictive factors for incomplete resection. These factors enable us to define target populations that could most benefit from complementary therapy along with surgery.

Large Nodular Fasciitis of the Shoulder Presenting as Soft Tissue Sarcoma: A Case Report.

CASE: This case report describes a patient who presented with clinical and radiographic features of a soft tissue sarcoma of the shoulder. Despite having a painless and relatively large mass, a biopsy and resection revealed nodular fasciitis (NF). CONCLUSION: This is an unusual case of a painless 10 cm mass that histopathologically was diagnosed as NF in the upper extremity with proximity to the axillary nerve and posterior humeral circumflex vessels. The USP6 rearrangement was helpful in confirming the diagnosis. Careful clinical, radiographic, and pathologic correlation is necessary in diagnosing these relatively rare tumors. In cases where there are discordant findings, molecular markers can be very helpful.

Surgical management of rare hepatobiliary sarcomas in a regional teaching hospital: a collaborative model for optimal care with case studies.

Sarcomas are challenging and conventionally referred to sarcoma specialist centres. In select cases with required surgical expertise, collaboration with a quaternary sarcoma centre rather than an upfront transfer of care may reduce logistic challenges without compromising patient care.We present a case series of three rare tumours of hepatobiliary origin-two cases of undifferentiated embryonal liver sarcoma in adults and one case of follicular dendritic sarcoma of the cystic lymph node.All three patients underwent surgery in a non-sarcoma specialist centre by hepatobiliary specialist surgeons with concurrent remote referrals to a sarcoma specialist quaternary centre. Both centres belong to the same cluster. R0 resection and no significant postoperative morbidity were achieved. All three patients currently remain disease-free.The unique and integrated healthcare systems within Singapore render cross-institution management possible. This case series suggests that an established setup for cross-centre collaboration facilitates wholistic patient care with good outcomes.

Management of a Complex, Recurrent Case of Medial Thigh Sarcoma With Pedicled Deep Inferior Epigastric Artery Perforator (DIEP) Lymphatic Flow-Through (LyFT) Flap and Secondary Anterolateral Thigh (ALT) Free Flap With Innervated Vastus Lateralis Anastomosed to Synthetic Artery Graft: A Case Report.

Soft-tissue sarcomas (STS) are rare solid tumors of mesenchymal cell origin and account for only 1% of adult malignancies. They tend to occur most commonly in the lower extremities. Reconstruction after sarcoma resection can be challenging, especially when important structures are involved and recurrences occur. Additionally, more attention is now being paid to reconstructing the lymphatic system to prevent lymphatic complications. In this case report, we presented the management of recurrent medial thigh sarcoma that necessitated multiple challenging reconstructions to provide valuable insights for lectures on similar cases. A 50-year-old male patient was diagnosed with an undifferentiated pleomorphic cell sarcoma (UPS) of the anteromedial thigh. After preoperative radiotherapy, a mass of 23 × 15 cm was removed, and reconstruction with a pedicled deep inferior epigastric artery perforator (p-DIEP) flap-based lymphatic flow through (LyFT) was performed. Six months later, the patient developed the first local recurrence with the presence of a distant metastasis. Following the tumor resection, the medial part of the DIEP flap was de-epithelized and buried in the defect for dead space obliteration. Another local recurrence arose 7 months after the second surgery. Therefore, a major debulking surgery involving the femoral neurovascular bundle was performed. The femoral artery was reconstructed with a synthetic graft, and the femoral vein with the great saphenous vein harvested from the contralateral thigh. A composite myocutaneous neurotized anterolateral thigh (ALT) flap from the contralateral thigh was used to obliterate the defect and restore the loss of function of the quadriceps femoris. Two lymphaticovenular anastomoses (LVAs) were performed at the ankle to reduce the risk of lymphatic sequelae. This case report highlights the importance of integrating various techniques to create a tailored approach that effectively addresses complex surgical requirements to avoid limb amputation and maintain functionality.

Preoperative discrimination between uterine myomas and sarcomas.

The narrative review article is focused on the strengths and limitations of modern imaging methods in the preoperative differential diagnosis of uterine mesenchymal tumours. In order to tailor the surgical procedures, imaging methods, namely ultrasound and magnetic resonance imaging (MRI), should be taken into account as well as clinical symptoms, age, and fertility plans. On ultrasound scans, uterine sarcomas have the appearance of large, usually solitary tumours of non-homogenous structure with irregular cysts, ill-defined outline borders (interrupted capsule), absence of calcifications with acoustic shadowing, and moderate to rich internal vascularisation. Rapid growth between follow-ups or atypical growth in peri- or post-menopause is also a sign of malignancy. On MRI, uterine sarcomas are characterized by irregular borders, hyperintense areas on T1-weighted and T2- weighted images, and central non-enhancing necrotic areas. On diffusion-weighted imaging (DWI/MRI), sarcomas exhibit markedly restricted diffusion but there is a significant overlap with some variants of fibroids. Core-needle or hysteroscopic biopsy can be used preoperatively if suspicious features are detected on ultrasound or MRI scans, particularly before myomectomy if fertility preservation is required or when conservative management is considered in asymptomatic women. Other imaging methods, such as positron emission tomography fused with CT (PET-CT) or computed tomography (CT) have limited role to distinguish uterine sarcomas from myomas and are suitable only for staging purposes. The importance of tumour markers including lactate dehydrogenase in preoperative work-up have not been verified yet. Conclusion: Uterine sarcomas can be distinguished from much more common myomas based on a combination of malignant features on ultrasound or MR imaging. In these suspicious cases the type and extent of surgery should be adjusted, avoiding intraperitoneal morcellation, which could lead to iatrogenic tumour spread and worsening of the patient's prognosis.

Clinicopathological and survival analysis for patients with uterine sarcoma treated following surgery for presumed benign disease.

OBJECTIVES: To investigate the clinicopathological characteristics and prognosis of patients with uterine sarcoma treated following surgery for presumed benign disease. METHODS: We identified all patients with uterine sarcoma found incidentally after primary surgery for presumed benign disease who presented to our institution and received re-exploration for completion surgery from January 1, 2004 to January 1, 2021. We analyzed the clinicopathological characteristics and prognosis. RESULTS: Overall, 95 patients were included in our study. For the initial surgery, myomectomy was performed in 50 (52.6%, 50/95) patients, hysterectomy was performed in 45 (47.4%, 45/95) patients. All patients were re-explored to complete the staging operation. The median time to the staging surgery was 40 days (range 15-90 days). There were 29 patients (30.5%, 29/95) had remnant sarcomas, with 17 patients (17/95, 17.9%) on the remaining uterus, 9 patients (9/95, 9.5%) had disseminated diseases, and 4 patients (4/95, 4.2%) had positive lymph nodes. About 40 patients (42.1%) received adjuvant chemotherapy, 55.2% (16/29) and 36.4% (24/66) patients with/without remnant diseases received adjuvant chemotherapy, respectively (P = 0.087). The median follow-up duration was 76.7 months (IQR: 34.8-118.1 months). And 17 patients (17.9%) had recurrence following re-exploration surgery. 5-year progression-free survival (PFS) and 5-year overall survival (OS) for the entire cohort was 81.7% and 92.1%, respectively. Patients with remnant sarcomas had a tendency towards a worse 5-year PFS and 5-year OS, compared with those without (5-year PFS: 75.6% vs. 84.5%, P = 0.224; 5-year OS: 85.5% vs. 95.1%, P = 0.217). Patients with disseminated diseases had a worse 5-year OS (62.5% vs. 95.1%, P = 0.007) and non-significantly worse 5-year PFS (64.8% vs. 83.4%, P = 0.153) compared with those without. CONCLUSIONS: Patients with uterine sarcoma treated following surgery for presumed benign disease have a favorable survival. Patients with disseminated diseases had a worse 5-year OS compared with those without. Surgical re-exploration may be valuable for removing remnant sarcomas and disseminated diseases.

Primary pleomorphic breast sarcoma - a case report.

Primary mammary sarcomas are very rare, histologically heterogeneous non-epithelial malignant neoplasms. Primary undifferentiated pleomorphic sarcoma is a rare malignant mesenchymal tumor in the breast. It is characterized by marked cellular atypism and pleomorphism. Isolated cases with an aggressive course and poor prognosis have been commonly described in the literature. We present a rare case of a 62-year-old woman with an 18-cm solid tumor of the left breast, 6 months old, which grew rapidly during the last month. Physical examination and mammography revealed no enlarged lymph nodes in the left axilla. A total mastectomy was performed. The diagnosis of undifferentiated pleomorphic sarcoma is challenging due to the lack of specific immunohistochemical markers. It can only be made after excluding other types of soft tissue sarcomas. This report discusses the histopathological and immunohistochemical studies that were conducted. Our case is distinguished from others with the same diagnosis by the atypical clinical presentation, which is painless, and the spontaneous bleeding, as well as the large size of the tumor.

Growth Rate and Outcomes in Locally Recurrent Extremity and Truncal Soft Tissue Sarcoma.

Importance: Improved prognostic tools are needed for patients with locally recurrent extremity or truncal soft tissue sarcoma (STS). Objective: To examine the association between average local recurrence (LR) growth rate and outcomes following resection of locally recurrent extremity or truncal STS. Design, Setting, and Participants: This retrospective cohort study used a prospectively maintained database from a single high-volume tertiary sarcoma referral center in the US to identify patients 16 years of age or older who underwent repeat resection of a locally recurrent extremity or truncal STS between July 1, 1982, and December 31, 2021. Patients with atypical lipomatous tumors, desmoid tumors, dermatofibrosarcoma protuberans, angiosarcomas, and prior or synchronous distant recurrence were excluded. Data were analyzed from November 1, 2022, to June 17, 2024. Exposure: Average LR growth rate, defined as the sum of recurrent tumor maximal diameters divided by the disease-free interval after index operation. Main Outcomes and Measures: The primary outcomes were cumulative incidences of disease-specific death (DSD), with death from other causes as a competing risk, and second LR, with death from any cause as a competing risk. Results: The study cohort included 253 patients (median [IQR] age, 64 [51-73] years; 140 [55.3%] male). The 5-year cumulative incidence of DSD after repeat resection was 29%. Multivariable analysis indicated that LR growth rate (hazard ratio [HR], 1.12 [95% CI, 1.08-1.18]; P < .001), younger age (HR, 0.98 [95% CI, 0.97-0.99]; P = .002), R1 or R2 margins (HR, 1.71 [95% CI, 1.03-2.84]; P = .04), high LR grade (HR, 2.90 [95% CI, 1.17-7.20]; P = .02), and multifocality (HR, 2.92 [95% CI, 1.70-5.00]; P < .001) were independently associated with higher incidence of DSD. Using the minimum P value method, the optimal cutoff for growth rate was found to be 0.68 cm/mo. Patients with values above this cutoff had higher 5-year incidences of DSD following repeat resection (63% vs 19%; permutation test P < .001) and higher amputation rates (19% vs 7%; P = .008). Only R1 margins were independently associated with higher incidence of second LR (HR, 1.81 [95% CI, 1.19-2.78]; P = .006). Conclusions and Relevance: In this cohort study of patients undergoing resection of a locally recurrent extremity or truncal STS, LR growth rate was independently associated with DSD. These findings suggest that patients with growth rates higher than 0.68 cm/mo who undergo LR resection may have high disease-specific mortality and amputation rates and should be considered for perioperative systemic therapy.

From Angiosomal to Bi-Angiosomal and Extra-Angiosomal Pedicled Perforator Flaps: Optimizing the Use of Local Tissues in Abdominal Wall Reconstruction.

INTRODUCTION: The use of free-style and propeller perforator-based flaps has been popularized for the reconstruction of moderate size defects in the trunk and extremities, while their application in the field of abdominal reconstruction is seldom reported. The purpose of this report is to describe the authors experience with the use of pedicled perforator-based flaps in abdominal wall reconstruction, presenting the innovative concept of transition from angiosomal to bi-angiosomal and extra-angiosomal perforator flaps and showing applications of the different flap designs according to the multiple clinical scenarios. PATIENTS AND METHODS: A total of 15 patients underwent abdominal wall reconstruction with angiosomal, bi-angiosomal, and extra-angiosomal pedicled perforator-based flaps harvested from the surrounding abdominal subunits for superficial or full thickness defects of the abdominal wall of moderate and large dimensions. The defects were consequent to soft-tissue sarcomas (STS) and non-melanoma skin cancer (NMSC) resection in 11 and 4 cases, respectively. Operative data, post-operative course, and complications were recorded. Moreover, at 12 months follow-up, patients were asked to rate the esthetic and functional outcomes of the reconstructive procedure on a 5-point Likert scale. RESULTS: Ten angiosomal perforator flaps (4 DIEP, 4 SCIP, 1 SEAP, and 1 LICAP flaps) and 5 bi-angiosomal and extra-angiosomal conjoined perforator flaps including different vascular territories (3 bilateral DIEP, 1 bilateral SEAP, and 1 ipsilateral DIEP-SEAP flap) were successfully transferred in 15 patients. In two patients, microsurgical anastomoses were performed to guarantee proper vascularization of the additional cutaneous territory. Mean age was 59.3 years. Defect sizes ranged from 98 to 408 cm2 (mean size was 194.7 cm2). Mean operative time was 280 min. Flap surface ranged from 108 to 336 cm2 (mean surface was 209.3 cm2). No major complications were registered. One bi-angiosomal bilateral DIEP flap suffered from partial necrosis and required an additional flap reconstruction. All patients underwent a 12-month follow-up except one, who did not show for clinical follow-up but responded at the Likert scale at clinical follow-up at 9 months. Overall patients' satisfaction was high, with mean esthetic and functional ratings of 4.27 and 3.87. CONCLUSION: The use of local tissues is an under-utilized solution in the field of abdominal wall reconstruction. Angiosomal, bi-angiosomal, and extra-angiosomal perforator flaps proved to be a reliable option to provide the transfer of a significant amount of tissue and offer like with like reconstruction while maximizing flap survival.

The mitotic rate as a prognostic biomarker after preoperative radiotherapy for high-grade limb/trunk soft tissue sarcoma.

PURPOSE: Currently there is no generally accepted standardized approach for the pathological evaluation of soft tissue sarcoma (STS) histology appearance after preoperative radiotherapy (PORT). This study aimed to investigate the prognostic value of pathological appearance after PORT for patients with high-grade limb/trunk STS. METHODS: A cohort of 116 patients with high-grade STS of the limb/trunk treated with PORT followed by resection were evaluated. Patient characteristics, imaging tumor morphology (size, volume), and histopathology (mitotic and necrosis rate, viable cell, hyalinization/fibrosis cytopathic effect) were reviewed and reassessed. Disease free survival (DFS) and overall survival (OS) were calculated using the Kaplan-Meier method, and the hazard ratio was derived from Cox proportional hazard models. Two predictive nomograms were calculated based on significant predictors identified. RESULTS: The 5-year DFS and OS were 52.9% and 70.3%, respectively. Tumor size before (HR:1.07, 95%CI: 1.01-1.14) and after PORT (HR:1.08, 95%CI: 1.01-1.14), tumor volume (HR:1.06, 95%CI: 1.01-1.12), mitotic rate after PORT (HR: 1.06, 95%CI: 1.02-1.11), mitotic rate change after PORT (HR:1.04, 95%CI:1.00-1.09) were independent risk factors for DFS. Tumor size before (HR:1.08, 95%CI: 1.03-1.14) and after PORT (HR:1.09, 95%CI: 1.04-1.15), tumor volume (HR:1.05, 95%CI: 1.01-1.09), mitotic rate after PORT (HR: 1.09, 95%CI: 1.04-1.13), mitotic rate change after PORT (HR:1.05, 95%CI:1.01-1.09) were independent risk factors for OS. The C-index of pathologic predictive nomogram based on mitotic rate for DFS and OS were 0.67 and 0.73, respectively. The C-index of morphology-pathology predictive nomogram for OS was 0.79. CONCLUSION: Tumor size before and after PORT, tumor volume, mitotic rate after PORT, mitotic rate change after PORT were independent risk factors for DFS and OS in high-grade STS patients treated with PORT. The mitotic rate, independent of tumor morphology, showed its potential as a prognostic biomarker for pathologic evaluation in patients treated with PORT.

Immediate and delayed flap reconstruction have equivalent outcomes and associated costs following soft tissue sarcoma surgery.

BACKGROUND AND OBJECTIVES: Surgical treatment of soft tissue sarcoma (STS) involves wide resection of the tumor, which can necessitate soft tissue reconstruction with local or free tissue flaps. This retrospective study compares cost, surgical and oncologic outcomes between patients undergoing reconstruction with immediate versus delayed flap coverage following STS resection. METHODS: Thirty-four patients who underwent planned flap reconstruction following resection of primary STS were identified retrospectively. Twenty-four (71%) received immediate reconstruction during the index surgery and 10 (29%) underwent planned delayed reconstruction. Preoperative patient-specific metrics, tumor characteristics, and surgical and patient outcomes were collected. Total hospital charges associated with every encounter during the perioperative period were obtained. RESULTS: Patient demographics, comorbidities, tumor metrics, and surgical characteristics were equivalent between groups. Postoperative wound complications, reoperations, readmissions, and disease-specific survival did not differ between cohorts. Costs associated with each reconstruction strategy were equivalent on bivariate and multivariate testing, when accounting for operating room time, hospital length of stay, and reoperation rate. CONCLUSIONS: Our study identifies no significant difference in patient outcome measures or cost between planned immediate and delayed flap reconstruction following STS resection. These results support the implementation of either treatment strategy in keeping with patient-centered, multidisciplinary care principles.

Contemporary surgical management of pediatric non-rhabdomyosarcoma soft tissue sarcoma.

Non-rhabdomyosarcoma soft tissue sarcoma (STS) comprises most STS in pediatric patients. It is a diverse set of over 30 histologic subtypes. Treatment is based on risk group determined by tumor size, grade, and the presence of metastases. Surgical resection is a cornerstone of therapy, as tumors are often resistant to chemotherapy or radiation. While patients with isolated tumors less than 5 cm may undergo upfront resection, strong consideration should be given to neoadjuvant chemoradiotherapy to ensure negative margins at surgical resection and optimal outcomes. Sentinel lymph node biopsy is strongly recommended for clear cell and epithelioid sarcomas. The most common metastatic site is the lung, and metastases should be resected at the end of therapy, when feasible. Unfortunately, many high-risk patients progress on therapy, and alternative strategies including earlier metastatic control require investigation.

Undifferentiated embryonal sarcoma of the liver in children: our experience in four difficult cases and three-dimensional practical exploration.

AIMS: To explore rare and difficult cases of undifferentiated embryonal sarcoma of the liver (UESL) in children in a single centre, summarize the diagnosis and treatment experience and analyse the role of a computer-assisted surgery system (Hisense CAS), thus providing a new global vision and three-dimensional perspective. METHODS: We retrospectively collected the clinical data including the diagnoses and treatment processes, of children with UESL confirmed by histopathological examination in our hospital from January 2009 to December 2020. The relationship between the tumour volume and important blood vessels and between the liver volume and tumour volume, as well as other three-dimensional characteristics in the reconstructed three-dimensional model were analysed using Hisense CAS. The findings from this analysis can be used to aid in surgical decision-making and preoperative planning. RESULTS: Four children-3 girls and 1 boy-with UESL were included in the study. The age at onset ranged from 6 to 8 years. All four children presented with symptoms of abdominal discomfort, and abdominal masses were detected during physical examination. Owing to the wishes of their parents and the possibility that the disease was benign, all four children underwent one-stage radical surgery. For patient 1, a three-dimensional reconstruction was created during the initial diagnosis, which made accurate evaluation and planning of the preoperative procedure challenging. In patient 2, the tumour was located in the middle lobe of the liver and involved the first and second hepatic hilum. For patient 3, the pathological diagnosis of the tumour after surgery was challenging, but eventually, the diagnosis was confirmed through histochemistry and consultation with higher-level hospitals. Patient 4 had a giant tumour, which had a preoperative simulated future liver remnant volume (FLV) that was 21.0% of the total volume of the liver and tumour (TLTV). According to the standard liver volume (SLV) for children, the FLV was 77.0% of the SLV, making surgery feasible. All four children underwent complete resection, and only patient 4 experienced recurrence below the diaphragm 19 months after surgery. Currently, the 3-year overall survival rate is 100%, and the 3-year event-free survival rate is 75%. CONCLUSION: UESL in children is rare, and the key to diagnosis and treatment is complete surgical resection. Through individualized three-dimensional surgical planning, accurate and complete resection of difficult and complex UESL in children can be achieved, leading to a favourable prognosis.

Detrimental effect of COVID-19 pandemic on patients with extremity bone sarcoma. Reference center experience.

1 BACKGROUND: COVID-19 pandemic had a major impact on the healthcare system globally. This work aims to evaluate COVID-19 impact on local treatment in bone sarcoma treated in a single, high-throughput institution. 2 METHODS: We have analyzed the local outcomes (i.e., possibility of limb sparing surgery) in all bone sarcoma patients treated between January 2016 and November 2022 in the main sarcoma reference center in Poland. Patients treated in the 2016-2019 period were regarded as "pre-pandemic" group, patients treated in 2020-2022 - "pandemic". Mann-Whitney U and Chi-square tests were used in the statistical analysis. No correction for multiple testing was applied. Tests with p < 0.05 were deemed significant. 3 RESULTS: There were 302 eligible patients identified. The group characteristics are presented in table 1. There were no differences in patient-related variables and histological subtypes of tumors between two groups. The tumor size did not differ (p = 0.053), when all tumor grades were considered, but high grade tumors were larger in the "pandemic" group (p = 0.034). This was reflected in the percentage of limb sparing surgeries which dropped from 83.3 % to 68.2 % ("pre-pandemic" vs. "pandemic", p = 0.004). This difference was even more stark in case of high grade tumors - 78 % vs. 54 % respectively (p = 0.001). 4 CONCLUSION: To our knowledge, this is the first report of the long lasting impact of COVID-19 pandemic on oncologic treatment outcomes in patients with malignant bone tumors.