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Abstract 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.

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]

Purpose: The purpose of this study was to evaluate the benefits of collaborative management between orthopedic surgery and WOC nurses in patients undergoing resection of subcutaneous sarcomas., Design: Retrospective case-control study., Subjects and Setting: The sample comprised 25 patients who underwent wide resection for soft tissue sarcoma, followed by 2-stage split-thickness skin grafting. Data collection occurred between January 2015 and April 2021 in a university hospital based in Kagoshima, Japan. For comparison, we categorized these patients into 2 groups: intervention group participants were managed by an orthopedic surgeon and a WOC nurse; nonintervention group members were managed without WOC nurse participation., Methods: Patient background and treatment-related information was retrospectively collected from medical records and compared between the WOC nurse intervention group and the nonintervention group, including maximum tumor diameter, surgical time, maximum skin defect diameter, length of hospital stay, and time from surgery to complete wound healing., Results: The average length of hospital stay was significantly shorter in the WOC nurse intervention group compared with the nonintervention group (38.3 days, SD = 8.0 vs 47.1 days, SD = 10.2; P = .023)., Conclusion: Collaborative wound management with a WOC nurse resulted in a shorter hospital length of stay when compared to traditional management with WOC nurse involvement. Based on these findings, we assert that WOC nurses provide an important bridge between postoperative wound management in patients undergoing resection of subcutaneous sarcomas., Competing Interests: The authors declare no conflicts of interest associated with this article., (Copyright © 2024 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of the Wound, Ostomy, and Continence Nurses Society.)

Background: Low-grade fibromyxoid sarcoma (LGFMS) is a rare type of sarcoma which is observed in the soft tissue of proximal extremities, typically in young and middle-aged adults. It consists of a solid proliferation of bland spindle cells within collagenous and myxoid stroma., Case Report: Herein, we report a case of LGFMS with massive degeneration and hyalinization. A 30-year-old man presented with a well-circumscribed mass measuring 15 cm in diameter in his left biceps femoris muscle. Marginal tumor resection was performed under the clinical diagnosis of an ancient schwannoma or chronic expanding hematoma (CEH). The resected tissue revealed a well-demarcated tumor mass with massive degeneration and hyalinization with focal calcification. Proliferation of spindle tumor cells with abundant collagenous stroma, which resembled the fibrous capsule of CEH, was observed exclusively in a small area of the periphery of the tumor. No nuclear palisading, myxoid stroma, or collagen rosettes were identified. Immunohistochemical analysis demonstrated that the spindle tumor cells expressed mucin 4 and epithelial membrane antigen. Reverse transcriptase-polymerase chain reaction analysis detected mRNA expression of fused in sarcoma::CAMP-responsive element binding protein 3-like protein 2 (FUS::CREB3L2) fusion gene. Thus, a final diagnosis of LGFMS with massive degeneration and FUS::CREB3L2 fusion was made., Conclusion: The recognition of massive degeneration and hyalinization as unusual features of LGFMS might be helpful to differentiate it from CEH and other benign spindle-cell tumors., (Copyright © 2023, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Liposarcoma rarely occurs in the pleura or thoracic cavity, and few reports appear in the literature. We hypothesized that combining clinicopathologic, immunohistochemical, and fluorescence in situ hybridization methods would allow definite diagnoses. Using formalin-fixed, paraffin-embedded blocks, we examined 6 atypical lipomatous tumor/well-differentiated liposarcomas (ALT/WDLPS), 5 dedifferentiated liposarcomas (DDLPSs), 2 pleomorphic liposarcomas, and 1 myxoid liposarcoma (MLPS). We used the Kaplan-Meier method and the Wilcoxon test for survival analysis for prognostic factor evaluation. Histologically, ALT/WDLPS was composed of a relatively mature adipocytic proliferation, accompanied by some lipoblasts. DDLPS exhibited round-to-oval tumor cells with a high nucleus-to-cytoplasm ratio that had proliferated in nests, accompanied in case 10 by some giant cells but no fatty cells. The pleomorphic type contained a varying proportion of pleomorphic lipoblasts. MLPS displayed uniform round- to oval-shaped cells and small signet-ring lipoblasts in a myxoid stroma. Immunohistochemically, 11 (79%), 11 (79%), and 10 (71%) of 14 cases were positive for S-100, p16, and CDK4, respectively. Six of the 14 cases (43%) were positive for MDM2 and adipophilin. One case of ALT/WDLPS and 3 cases of DDLPS exhibited MDM2 amplification by fluorescence in situ hybridization (Vysis LSI MDM2 SpectrumGreen Probe plus Vysis CEP 12 SpectrumOrange probe). ALT/WDLPS was the most favorable type for survival, while adipophilin tended to be a negative prognostic factor for pleural liposarcoma. For a firm diagnosis of liposarcoma in the pleura, immunohistochemistry for CDK4, MDM2, and adipophilin together with MDM2 gene amplification by fluorescence in situ hybridization may be an important diagnostic tool., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Histological distinction between enchondroma and chondrosarcoma is difficult because of a lack of definitive biomarkers. Here, we found highly active transforming growth factor-β (TGF-β) and bone morphogenetic protein (BMP) signalling in human chondrosarcomas compared with enchondromas by immunohistochemistry of phosphorylated SMAD3 and SMAD1/5. In contrast, the chondrogenic master regulator SOX9 was dramatically down-regulated in grade 1 chondrosarcoma. Paternally expressed gene 10 (PEG10) was identified by microarray analysis as a gene overexpressed in chondrosarcoma SW1353 and Hs 819.T cells compared with C28/I2 normal chondrocytes, while TGF-β1 treatment, mimicking higher grade tumour conditions, suppressed PEG10 expression. Enchondroma samples exhibited stronger expression of PEG10 compared with chondrosarcomas, suggesting a negative association of PEG10 with malignant cartilage tumours. In chondrosarcoma cell lines, application of the TGF-β signalling inhibitor, SB431542, increased the protein level of PEG10. Reporter assays revealed that PEG10 repressed TGF-β and BMP signalling, which are both SMAD pathways, whereas PEG10 knockdown increased the level of phosphorylated SMAD3 and SMAD1/5/9. Our results indicate that mutually exclusive expression of PEG10 and phosphorylated SMADs in combination with differentially expressed SOX9 is an index to distinguish between enchondroma and chondrosarcoma, while PEG10 and TGF-β signalling are mutually inhibitory in chondrosarcoma cells.

Human immunodeficiency virus type 1 enhancer-binding protein 3 (Hivep3) suppresses osteoblast differentiation by inducing proteasomal degradation of the osteogenesis master regulator Runx2. In this study, we tested the possibility of cooperation of Hivep1, Hivep2, and Hivep3 in osteoblast and/or chondrocyte differentiation. Microarray analyses with ST-2 bone stroma cells demonstrated that expression of any known osteochondrogenesis-related genes was not commonly affected by the three Hivep siRNAs. Only Hivep3 siRNA promoted osteoblast differentiation in ST-2 cells, whereas all three siRNAs cooperatively suppressed differentiation in ATDC5 chondrocytes. We further used microarray analysis to identify genes commonly down-regulated in both MC3T3-E1 osteoblasts and ST-2 cells upon knockdown of Hivep3 and identified asparagine-linked glycosylation 2 (Alg2), which encodes a mannosyltransferase residing on the endoplasmic reticulum. The Hivep3 siRNA-mediated promotion of osteoblast differentiation was negated by forced Alg2 expression. Alg2 suppressed osteoblast differentiation and bone formation in cultured calvarial bone. Alg2 was immunoprecipitated with Runx2, whereas the combined transfection of Runx2 and Alg2 interfered with Runx2 nuclear localization, which resulted in suppression of Runx2 activity. Chondrocyte differentiation was promoted by Hivep3 overexpression, in concert with increased expression of Creb3l2, whose gene product is the endoplasmic reticulum stress transducer crucial for chondrogenesis. Alg2 silencing suppressed Creb3l2 expression and chondrogenesis of ATDC5 cells, whereas infection of Alg2-expressing virus promoted chondrocyte maturation in cultured cartilage rudiments. Thus, Alg2, as a downstream mediator of Hivep3, suppresses osteogenesis, whereas it promotes chondrogenesis. To our knowledge, this study is the first to link a mannosyltransferase gene to osteochondrogenesis.

Although bone morphogenic protein (BMP) signaling promotes chondrogenesis, it is not clear whether BMP-induced chondrocyte maturation is cell-autonomously terminated. Loss of function of Smpd3 in mice results in an increase in mature hypertrophic chondrocytes. Here, we report that in chondrocytes the Runx2-dependent expression of Smpd3 was increased by BMP-2 stimulation. Neutral sphingomyelinase 2 (nSMase2), encoded by the Smpd3 gene, was detected both in prehypertrophic and hypertrophic chondrocytes of mouse embryo bone cartilage. An siRNA for Smpd3, as well as the nSMase inhibitor GW4869, significantly enhanced BMP-2-induced differentiation and maturation of chondrocytes. Conversely, overexpression of Smpd3 or C2-ceramide, which mimics the function of nSMase2, inhibited chondrogenesis. Upon induction of Smpd3 siRNA or GW4869, phosphorylation of both Akt and S6 proteins was increased. The accelerated chondrogenesis induced by Smpd3 silencing was negated by application of the Akt inhibitor MK2206 or the mammalian target of rapamycin inhibitor rapamycin. Importantly, in mouse bone culture, GW4869 treatment significantly promoted BMP-2-induced hypertrophic maturation and calcification of chondrocytes, which subsequently was eliminated by C2-ceramide. Smpd3 knockdown decreased the apoptosis of terminally matured ATDC5 chondrocytes, probably as a result of decreased ceramide production. In addition, we found that expression of hyaluronan synthase 2 (Has2) was elevated by a loss of Smpd3, which was restored by MK2206. Indeed, expression of Has2 protein decreased in nSMase2-positive hypertrophic chondrocytes in the bones of mouse embryos. Our data suggest that the Smpd3/nSMase2-ceramide-Akt signaling axis negatively regulates BMP-induced chondrocyte maturation and Has2 expression to control the rate of endochondral ossification as a negative feedback mechanism.