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Introduction: Calcifying fibrous pseudotumor is a rare benign soft-tissue lesion composed of fibrous tissue with abundant hyalinized collagen and dystrophic and often psammomatous calcifications. The cause of the disease is unclear but, usually, complete resection of the well-circumscribed tumor is sufficient to avoid recurrence of the disease. Here, we report an unusual case of this rare tumor that presented as two lobulated lesions in the calf muscle.Case Presentation: The patient was a 17-year-old Japanese girl who noted a hard mass in her left calf. Magnetic resonance imaging revealed two well-demarcated lobular masses in the soleus muscle, and the tumor was significantly enhanced by contrast medium. Preoperative differential diagnoses included soft-part tumors composed of fibrous tissue. However, making a definite diagnosis was impossible because a lobulated shape is rare for fibrous tumors. Biopsy demonstrated that the mass was a benign tumor composed of collagen-rich, hyalinized fibrosclerotic tissue. We performed marginal resection of the two nodules, including the fibrous tissue that connected them. Immunohistochemistry was positive for factor XIIIa and negative for anaplastic lymphoma kinase-1. These findings were helpful to distinguish calcifying fibrous pseudotumor from inflammatory myofibroblastic tumor. There was no sign of recurrence at 30 months after surgery.Conclusion: To the best of our knowledge, this is the first case of bilobular calcifying fibrous pseudotumor that developed in an extremity. As described in the previous literature, simple excision was sufficient for the treatment of calcifying fibrous pseudotumor with two lobules. [ABSTRACT FROM AUTHOR]

Recently, we reported highly active transforming growth factor (TGF)-β and bone morphogenetic protein (BMP) signaling in human chondrosarcoma samples and concurrent downregulation of paternally expressed gene 10 (PEG10). PEG10 expression was suppressed by TGF-β signaling, and PEG10 interfered with the TGF-β and BMP-SMAD pathways in chondrosarcoma cells. However, the roles of PEG10 in bone tumors, including chondrosarcoma, remain unknown. Here, we report that PEG10 promotes SW1353 chondrosarcoma cell growth by preventing TGF-β1-mediated suppression. In contrast, PEG10 knockdown augments the TGF-β1-induced motility of SW1353 cells. Individually, TGF-β1 and PEG10 siRNA increase AKT phosphorylation, whereas an AKT inhibitor, MK2206, mitigates the effect of PEG10 silencing on cell migration. SW1353 cell invasion was enhanced by BMP-6, which was further increased by PEG10 silencing. The effect of siPEG10 was suppressed by inhibitors of matrix metalloproteinase (MMP). BMP-6 induced expression of MMP-1, -3, and -13, and PEG10 lentivirus or PEG10 siRNA downregulated or further upregulated these MMPs, respectively. PEG10 siRNA increased BMP-6-induced phosphorylation of p38 MAPK and AKT, whereas the p38 inhibitor SB203580 and MK2206 diminished SW1353 cell invasion by PEG10 siRNA. SB203580 and MK2206 impeded the enhancing effect of PEG10 siRNA on the BMP-6-induced expression of MMP-1, -3, and -13. Our findings suggest dual functions for PEG10: accelerating cell growth by suppressing TGF-β signaling and inhibiting cell motility and invasion by interfering with TGF-β and BMP signaling via the AKT and p38 pathways, respectively. Thus, PEG10 might be a molecular target for suppressing the aggressive phenotypes of chondrosarcoma cells. [ABSTRACT FROM AUTHOR]

Simple Summary: We aimed to elucidate the long-term outcomes of a distal femur reconstruction system in 125 patients with bone and soft tissue tumors. Implant survival rates at 10 and 15 years were 58.5% and 39.4%. Stem breakage should be considered in patients with cementless and/or smaller femoral stem sizes. Aseptic loosening should be considered in patients with a cement system after 10 years. Background: The distal femur is a common site of bone tumors. After surgical resection, prosthetic replacement is a major reconstruction method. We aimed to elucidate the long-term outcomes of the Kyocera Modular Limb Salvage (KMLS) systems after resection of tumors in the distal part of the femur. Methods: Between 1998 and 2014, 125 patients were treated at 14 institutions. There were 59 males and 66 females, with a mean age of 35 years. The mean follow-up period was 132 months. Results: There had been 65 additional surgeries, including 56 revisions and 9 amputations: 15 for aseptic loosening, 14 for stem breakage, 13 for deep infection, 13 for rotator-hinge bushing failure, 5 for local recurrence, and 5 for others. Implant survival rates at 10 and 15 years were 58.5% and 39.4%. The cumulative incidence of 15-year revision for femoral stem breakage was 31.7% in patients with cementless fixation. The 15-year cumulative incidence of revision for aseptic loosening was 19.8% in patients with cement fixation. Conclusions: KMLS systems represent a reliable system with long-term results. Stem breakage should be considered in patients with cementless and/or smaller femoral stem sizes. Aseptic loosening should be considered in patients with cement systems after 10 years. [ABSTRACT FROM AUTHOR]