[Clinicopathological and molecular features of small round cell sarcoma of bone and soft tissue: a study of 72 cases].

Objective: To investigate the clinicopathological, immunohistochemical and molecular features of small round cell sarcoma (SRCS) of the bone and soft tissue, and to compare the diagnostic value of different techniques. Methods: Seventy-two cases of SRCS of the bone and soft tissue diagnosed at People's Hospital, Peking University from January 2016 to March 2020 were recruited and retrospectively analyzed for pathological morphology, immunophenotype and fluorescence in situ hybridization (FISH) data. Next generation sequencing (NGS) was performed on 13 difficult cases. Results: In the study cohort, the patients ranged in age from 4-55 years, with a male predominance. The most Ewing's sarcomas and osteosarcomas occurred in the bone, while CIC-rearranged sarcomas, BCOR-rearranged sarcoma, synovial sarcoma, extraskeletal myxoid chondrosarcoma and FUS-NFATc2 rearranged sarcoma occurred in soft tissue. Histologically, all cases were composed predominantly of small round cells. Most cases were positive for vimentin and CD99, and showed a variable reactivity for neurogenic markers. Muscle marker and epithelial marker were negative for most cases. Combined with clinical features, histopathologic findings, immunophenotype, FISH and NGS, we diagnosed 46 Ewing sarcomas, 14 osteosarcomas, 3 CIC-rearranged sarcomas, 1 BCOR-rearranged sarcoma, 1 synovial sarcoma, 1 clear cell soft tissue sarcoma, 1 extraskeletal myxoid chondrosarcoma, 1 FUS-NFATc2 rearranged sarcoma, and 4 undifferentiated small round cell sarcomas. Conclusions: SRCS of bone and soft tissue is a group of malignant mesenchymal tumors based on morphological features. Most cases can be diagnosed with a combination of clinical characteristics, morphological features and immunohistochemical phenotype, while some cases require such further tests as FISH and NGS technologies, and NGS can be useful in diagnosing and categorizing SRCS.

[The prevention and management of approach-specific complications of abdominal aortic balloon occlusion in pelvic and sacral surgery].

Objective: To investigate the causes,prevention and treatment of femoral artery puncture related complications caused by the application of resuscitative endovascular balloon occlusion of the aorta (REBOA) in the resection of pelvic and sacral tumors. Methods: Clinical data of 23 patients with femoral artery puncture related complications who received REBOA in the resection of pelvic and sacral tumors from August 2010 to August 2018 at the Musculoskeletal Tumor Center,Peking University People's Hospital were retrospectively analyzed.There were 8 males and 15 females,with the an age of (37.0±16.2) years (range:15 to 65 years).Arterial access via the Seldinger technique for REBOA was obtained in the right common femoral artery of 18 cases,and in the left of 6 cases.An arterial sheath with a diameter of 11 to 12 F(1 F≈0.33 mm) was used for the patient.The occurrence and treatment of postoperative complications were analyzed. Results: Acute femoral arterial thrombosis occurred in 18 patients,which was managed by open repair 48 hours postoperatively.Among the 349 patients admitted before 2015 who received hemostasis by compression after femoral artery sheath removal,12 patients (3.4%) developed acute femoral artery thrombosis.While the 476 patients admitted after 2015 who used a vascular stapler to close the femoral artery wound,6 patients (1.3%) developed acute femoral artery thrombosis.One case of retroperitoneal hematoma and 1 case of femoral pseudoaneurysm were found and surgically fixed.Postoperative follow-up was (40±18) months (range:13 to 108 months).Three cases with chronic lower extremity ischemia were confirmed by Doppler ultrasonography during 1 to 5 years follow-up.Two of them had minimal symptoms and denied further treatment,while the other one received femoral-femoral artery bypass surgery to restore distal flow for pain and numbness relief. Conclusions: Acute femoral arterial thrombosis was the most common femoral artery puncture.Technique refinement of REBOA,the use of percutaneous suture device and close follow-up can reduce the approach-specific complications,and help to detect and treat the complications timely,which may popularize the clinical application of REBOA.

[Rasfonin inhibits proliferation and migration of osteosarcoma 143B cells].

OBJECTIVE: To investigate the effects of rasfonin, a fungal secondary metabolite, on the proliferation and migration of osteosarcoma 143B cells. METHODS: 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) assay was performed to examine 143B cell viability following treatment of rasfonin. Using dimethyl sulfoxide (DMSO) group as control, cell viability was detected when 143B cells were treated with rasfonin (3 µmol/L and 6 µmol/L) for 12 or 24 hours. The effect of rasfonin on colony forming ability was detected by clone formation assay. 143B cells treated with DMSO or rasfonin (3 µmol/L) for one week, and the number of clones formed in the two groups was counted. Wound healing and transwell assay were employed to analyze cell invasion and migration upon rasfonin challenge. The DMSO group was used as control while rasfonin (3 µmol/L) was used for 24 hours. The wound healing rate and the number of invasive cells were compared between the two groups. The intracellular autophagosomes were monitored by transmission electron microscopy when 143B cells were treated with DMSO or rasfonin (3 µmol/L) for 4 hours. The expression of p62, microtubule-associated protein 1 light chain 3 fusion protein (LC3) and poly (ADP-ribose) polymerase-1 (PARP-1) in response to rasfonin were detected by immunoblotting assay. RESULTS: Rasfonin reduced the viability of 143B cells in a dose-dependent manner (12 h: F=31.36, P<0.01; 24 h: F=67.07, P<0.01). Rasfonin (3 µmol/L) completely inhibited the clonal formation of 143B cells (P<0.01). The wound healing result revealed that rasfonin significantly decreased migratory ability of 143B cells (33.91%±0.83% vs. 65.11%±0.94%, P<0.01), whereas its treatment significantly reduced the number of 143B cells penetrating through Matrigel-containing basement membrane (21.33±1.45 vs. 49.33±2.40, P<0.01). Compared with the control group, rasfonin markedly increased the number of autophagic vacuoles. The immunoblotting results revealed that rasfonin increased LC3-II accumulation and decreased p62 levels. Choloroquine (CQ), an often used autophagic inhibitor, further accumulated rasfonin-induced LC3-II. In addition, rasfonin appeared to cause the cleavage of PARP-1. CONCLUSION: Rasfonin induced autophagy and activated caspase-dependent apoptosis in 143B cells concurring with suppressing the proliferation and migration of the cells; these results provide an experimental basis for rasfonin as a potential therapeutic agent for osteosarcoma.

Surgical treatment of primary malignant tumours of the distal tibia: clinical outcome and reconstructive strategies.

AIMS: We retrospectively report our experience of managing 30 patients with a primary malignant tumour of the distal tibia; 25 were treated by limb salvage surgery and five by amputation. We compared the clinical outcomes of following the use of different methods of reconstruction. PATIENTS AND METHODS: There were 19 male and 11 female patients. The mean age of the patients was 19 years (6 to 59) and the mean follow-up was 5.1 years (1.25 to 12.58). Massive allograft was used in 11 patients, and autograft was used in 14 patients. The time to union, the survival time of the reconstruction, complication rate, and functional outcomes following the different surgical techniques were compared. The overall patient survival was also recorded. RESULTS: Out of 14 patients treated with an autograft, 12 (86%) achieved union at both the proximal and distal junctions. The time to union at both junctions of the autograft was significantly shorter than in those treated with an allograft (11.1 vs 17.2 months, p = 0.02; 9.5 vs 16.2 months, p = 0.04). The complication rate of allograft reconstruction was 55%. The five patients treated with an amputation did not have a complication. Out of the 25 patients who were treated with limb salvage, three (12%) developed local recurrence and underwent amputation. The mean functional Musculoskeletal Tumor Society (MSTS) score after autograft reconstruction was higher than after allograft reconstruction (81% vs 67%; p = 0.06), and similar to that after amputation (81% vs 82%; p = 0.82). The two- and five-year overall rates of survival were 83% and 70%, respectively. CONCLUSIONS: This consecutive case series supports the safety of limb salvage and the effectiveness of biological reconstruction after the resection of a primary tumour of the distal tibia. Autograft might be a preferable option. In some circumstances, below-knee amputation remains a valid option.