Preoperative Denosumab Therapy Against Giant Cell Tumor of Bone is Associated with an Increased Risk of Local Recurrence After Curettage Surgery.

INTRODUCTION: Denosumab has been shown to be highly effective at suppressing the progression of giant cell tumor of bone (GCTB). However, recent studies have observed a potential increased risk of local recurrence after surgery following the use of denosumab, raising concerns on the use of this agent against GCTB in combination with surgery. METHODS: We retrospectively reviewed the medical records of 234 patients with GCTB who were surgically treated at multiple institutions from 1990 to 2017. Patient background, tumor characteristics, treatment methods, local recurrence-free survival rate, distant metastasis rate, oncologic outcome, and limb function at final follow-up were analyzed and compared between cases treated with and without denosumab. RESULTS: The 3-year local recurrence-free survival rate was significantly lower in patients who underwent preoperative denosumab therapy (35.3%) compared with those treated without denosumab (79.9%) (P < 0.001). Among patients who were preoperatively treated with denosumab, those who had a local recurrence all underwent curettage surgery. CONCLUSIONS: Preoperative denosumab therapy in combination with curettage surgery was significantly associated with an increased risk of local recurrence in Campanacci grade 3 tumors. Our data suggest that clinicians seeing GCTB patients should be aware to this increased risk when planning preoperative denosumab therapy.

Complications of surgery for giant cell tumor of bone in the extremities: Incidence, risk factors, management modality, and impact on functional and oncological outcomes.

BACKGROUND: Due to the wide variations in location, size, local invasiveness, and treatment options, the complications associated with surgery for giant cell tumor of bone have been sporadically reported. For quality assessment, fundamental data based on large-scale surveys of complications under a universal evaluation system is needed. The Dindo-Clavien classification is an evaluation system for complications based on severity and required intervention type and is suitable for the evaluation of surgery in a heterogeneous cohort. METHODS: A multi-institutional retrospective survey of 141 patients who underwent surgery for giant cell tumor of bone in the extremity was performed. The incidence and risk factors of complications, type of intervention for complication control, and impact of complications on functional and oncological outcomes were analyzed using the Dindo-Clavien classification. RESULTS: Forty-six cases (32.6%) had one or more complications. Of them, 18 (12.8%), 11 (7.8%), and 17 (12.1%) cases were classified as Dindo-Clavien classification grade I, II, and III complications, respectively. There were no cases with grade IV or V complications. Progression in Campanacci grading (p = 0.04), resection (over curettage, p < 0.0001), reconstruction with prosthesis (p = 0.0007), and prolonged operative duration (p = 0.0002) were significant risk factors for complications. Complications had a significant impact on function (p < 0.0001). Differences in the impact of complication types and tumor location on function were confirmed. Complications had no impact on local recurrence and metastasis development. CONCLUSION: The Dindo-Clavien classification could provide fundamental information, under a uniform definition and classification system, on postoperative complications in patients with giant cell tumor of bone in terms of incidence, type of intervention for complication control, risk factors, and impact on functional outcome. The data are useful not only for preoperative evaluation for the risk of complications under specific conditions but also for quality assessment of surgery for giant cell tumor of bone.

Pseudomyogenic hemangioendothelioma of bone treated with denosumab: a case report.

BACKGROUND: Pseudomyogenic hemangioendothelioma (PMHE) is a rare endothelial neoplasm that involves the bones in only 14% of all cases. The optimal treatment strategy has not been established. We herein report a case of primary PMHE in which denosumab treatment showed activity in both imaging studies and the clinical outcome. CASE PRESENTATION: A 20-year-old woman presented with worsening pain in her left ankle. Imaging studies showed multifocal fluorodeoxyglucose (FDG)-avid [maximum standardized uptake value (SUVmax), 15.95] osteolytic lesions in the bones of her left lower extremity. While waiting for the definitive pathologic diagnosis of PMHE, denosumab, a human immunoglobulin G2 monoclonal antibody against RANKL, was initiated to treat progressive bone absorption after curettage of one of the lesions. Denosumab induced osteosclerosis around the lesions and pain relief and was discontinued 4 years after its initiation. Although all of the multifocal lesions remained, they all became less FDG-avid (SUVmax, 2.6), and the patient developed no signs of new lesions or distant metastasis. CONCLUSION: Denosumab plays a certain role in prevention of bone destruction by PMHE through suppression of osteoclast-like giant cells and would be an excellent treatment for bone absorption by PMHE of bone.

Wide-spread ignorance on the treatment of subcutaneous malignant tumors; a questionnaire-based study.

BACKGROUND: Subcutaneous malignant tumors are often treated by non-specialized clinicians in musculoskeletal oncology. While the resection of subcutaneous tumors appears technically feasible, unplanned resection of malignant tumors can result in a devastating clinical outcome. The aim of this study was to evaluate the potential estrangement in the awareness of and the treatment strategy for the patients with subcutaneous soft tissue tumors between musculoskeletal oncologists and non-specialized clinicians. METHODS: A questionnaire probing the clinical assessment of subcutaneous tumors was sent to orthopedic surgeons, dermatologists, plastic surgeons, and general surgeons. Results of the questionnaire were statistically analyzed. RESULTS: One hundred sixteen clinicians out of 150 responded to the questionnaire; the response rate was 77.3%. Among those, 46 clinicians had treated subcutaneous tumors. Thirty-nine of these 46 clinicians (27 musculoskeletal oncologists and 12 non-specialized clinicians) preoperatively performed enhanced MRI for diagnostic evaluation. Preoperative incisional biopsy to confirm the pathological diagnosis was performed by 36 of the 46 clinicians (29 musculoskeletal oncologists and seven non-specialized clinicians). These results indicate that musculoskeletal oncologists perform preoperative enhanced MRI (P = 0.08) and biopsy (P < 0.01) more frequently than non-specialized clinicians. The recognition rate of 'myxofibrosarcoma' was 60.8% among clinicians with an experience with sarcoma treatment (25 musculoskeletal oncologists and three non-specialized clinicians). The recognition rate of 'myxofibrosarcoma' between musculoskeletal oncologists and non-specialized clinicians was statistically significant (P < 0.01). CONCLUSIONS: Preoperative evaluations for subcutaneous tumors are more often inappropriate in non-specialized clinicians than those who are. Therefore, it will be mandatory to raise the awareness of this condition to improve the clinical outcome of patients with subcutaneous tumors.

CT guided cryoablation for locally recurrent or metastatic bone and soft tissue tumor: initial experience.

BACKGROUND: Historically, local control of recurrent sarcomas has been limited to radiotherapy when surgical re-resection is not feasible. For metastatic carcinomas to the bone or soft tissue, radiotherapy and some interventional radiology treatment along with other systemic therapies have been widely advocated due to the possibility of disseminated disease. These techniques are effective in alleviating pain and achieving local control for some tumor types, but it has not been effective for prolonged local control of most tumors. Recently, cryoablation has been reported to have satisfactory results in lung and liver carcinoma treatment. In this study, we analyzed the clinical outcome of CT-guided cryoablation for malignant bone and soft tissue tumors to elucidate potential problems associated with this procedure. METHODS: Since 2011, 11 CT-guided cryoablations in 9 patients were performed for locally recurrent or metastatic bone and soft tissue tumors (7 males and 2 females) at our institute. The patients' average age was 74.8 years (range 61-86) and the median follow up period was 24.1 months (range 5-48). Histological diagnosis included renal cell carcinoma (n = 4), dedifferentiated liposarcoma (n = 2), myxofibrosarcoma (n = 2), chordoma (n = 1), hepatocellular carcinoma (n = 1), and thyroid carcinoma (n = 1). Cryoablation methods, clinical outcomes, complications, and oncological outcomes were analyzed. RESULTS: There were 5 recurrent tumors and 6 metastatic tumors, and all cases had contraindication to either surgery, chemotherapy or radiotherapy. Two and 3 cycles of cryoablation were performed for bone and soft tissue tumors, respectively. The average length of the procedure was 101.1 min (range 63-187), and the average number of probes was 2.4 (range 2-3). Complications included 1 case of urinary retention in a patient with sacral chordoma who underwent prior carbon ion radiotherapy, 1 transient femoral nerve palsy, and 1 minor wound complication. At the final follow up, 4 patients showed no evidence of disease, 2 were alive with disease, and 3 died of disease. CONCLUSIONS: Reports regarding CT-guided cryoablation for musculoskeletal tumors are rare and the clinical outcomes have not been extensively studied. In our case series, CT-guided cryoablation had analgesic efficacy and there were no cases of local recurrence post procedure during the follow-up period. Although collection of further data regarding use of this technique is necessary, our data suggest that cryoablation is a promising option in medically inoperable musculoskeletal tumors.

Results of sub-analysis of a phase 2 study on trabectedin treatment for extraskeletal myxoid chondrosarcoma and mesenchymal chondrosarcoma.

BACKGROUND: Trabectedin is reported to be particularly effective against translocation-related sarcoma. Recently, a randomized phase 2 study in patients with translocation-related sarcomas unresponsive or intolerable to standard chemotherapy was conducted, which showed clinical benefit of trabectedin compared with best supportive care (BSC). Extraskeletal myxoid chondrosarcoma (EMCS) and Mesenchymal chondrosarcoma (MCS) are very rare malignant soft tissue sarcomas, and are associated with translocations resulting in fusion genes. In addition, the previous in vivo data showed that trabectedin affect tumor necrosis and reduction in vascularization in a xenograft model of a human high-grade chondrosarcoma. The aim of the present analysis was to clarify the efficacy of trabectedin for EMCS and MCS subjects in the randomized phase 2 study. METHODS: Five subjects with EMCS and MCS received trabectedin treatment in the randomized phase 2 study. Three MCS subjects were allocated to the BSC group. Objective response and progression-free survival (PFS) were assessed according to the Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 by central radiology imaging review. RESULTS: The median follow-up time of the randomized phase 2 study was 22.7 months, and one subject with MCS was still receiving trabectedin treatment at the final data cutoff. The median PFS was 12.5 months (95 % CI: 7.4-not reached) in the trabectedin group, while 1.0 months (95 % CI: 0.3-1.0 months) in MCS subjects of the BSC group. The six-month progression-free rate was 100 % in the trabectedin group. One subject with MCS showed partial response, and the others in the trabectedin group showed stable disease. Overall survival of EMCS and MCS subjects was 26.4 months (range, 10.4-26.4 months) in the trabectedin group. At the final data cutoff, two of five subjects were still alive. CONCLUSIONS: This sub-analysis shows that trabectedin is effective for patients with EMCS and MCS compared with BSC. The efficacy results were better than previously reported data of TRS. These facts suggest that trabectedin become an important choice of treatment for patients with advanced EMCS or MCS who failed or were intolerable to standard chemotherapy. TRIAL REGISTRATION: The randomized phase 2 study is registered with the Japan Pharmaceutical Information Center, number JapicCTI-121850 (May 31, 2012).

Novel MR imaging method--MAVRIC--for metal artifact suppression after joint replacement in musculoskeletal tumor patients.

BACKGROUND: Standard imaging modality for the follow-up after prosthetic replacements for musculoskeletal tumor patients has been conventional radiography. This technique is effective in detecting subtle changes in bone adjacent to metal implants, but in many cases, radiographs do not lead to definitive diagnosis of postoperative adverse events such as acute infection, local recurrence of soft tissue tumor or soft tissue local recurrence of osseous sarcoma. Conventional MRI sequences have not been effective due to metal artifacts. In this study, we tried to elucidate the effectiveness of metal artifact suppression using novel sequence, multiacquisition variable-resonance image combination (MAVRIC), after musculoskeletal tumor surgeries. METHODS: We retrospectively analyzed 5 cases of malignant bone and soft tissue sarcoma patients who were reconstructed with metal prosthesis after wide resection of tumors. Images obtained using MAVRIC and short tau inversion recovery (STIR) were compared side by side. The paired MAVRIC and STIR images were qualitatively compared independently by two specialists for 4 parameters: visualization of bone - implant interface, visualization of surrounding soft tissues, image blurring, and overall image quality. Quantitatively, paired images were reviewed to identify the slice where the metal artifact was maximal, and a region of interest encompassing the implant and surrounding artifact was drawn using Advantage Workstation (GE Healthcare, Japan). RESULTS: There were no local recurrences that were detected. By utilizing MAVRIC, visualization of the bone - implant interface and visualization of the surrounding soft tissue were significantly improved in MAVRIC compared to STIR. Although blurring was worse on the MAVRIC acquisitions, the overall image quality was still better on MAVRIC. Quantitatively, the area of metal artifact measured using MAVRIC was markedly less compared to STIR (61.4 cm(2) vs 135.9 cm(2)). CONCLUSION: Despite the relatively small number of cases in the present study, our observation strongly suggests that MAVRIC is able to improve the quality of images by decreasing the artifact caused by endoprosthesis, frequently utilized in reconstruction of musculoskeletal tumor patients. Further installments of conventional imaging sequences with the addition of gadolinium - enhancement will enable increased accuracy in diagnosing local recurrences of sarcoma patients.

Participation of the Fas/FasL signaling pathway and the lung microenvironment in the development of osteosarcoma lung metastases.

The lungs are the most common site for the metastatic spread of osteosarcoma. Success in using chemotherapy to improve overall survival has reached a plateau. Understanding the biologic properties that permit osteosarcoma cells to grow in the lungs may allow the identification of novel therapeutic approaches-the goal being to alter the tumor cells' expression of cell surface proteins so that there is no longer compatibility with the metastatic niche. We have demonstrated that the Fas Ligand positive (FasL(+)) lung microenvironment eliminates Fas(+) osteosarcoma cells that metastasize to the lungs. Indeed, osteosarcoma lung metastases from patients are Fas(-), similar to what we found in several different mouse models. The Fas(+) cells are cleared from the lungs through apoptosis induced by the Fas signaling pathway following interaction of Fas on the tumor cell surface with the lung FasL. Blocking the Fas signaling pathway interferes with this process, allowing the Fas(+) cells to grow in the lungs. Our investigations show that Fas expression in osteosarcoma cells is regulated epigenetically by the micro-RNA miR-20a, encoded by the miR-17-92 cluster. Our studies support the feasibility of finding agents that can re-induce Fas expression as a novel therapeutic approach to treat osteosarcoma patients with lung metastases. We have identified two such agents, the histone deacetylase inhibitor entinostat and the chemotherapeutic agent gemcitabine (GCB). Aerosol GCB and oral entinostat induce the upregulation of Fas and the regression of established osteosarcoma lung metastases. Aerosol GCB was not effective in the FasL-deficient gld mouse confirming that the lung microenvironment was central to the success of this therapy. Our studies establish the critical role of the lung microenvironment in the metastatic process of osteosarcoma to the lungs and suggest an alternative focus for therapy, that is, incorporating the lung microenvironment as part of the treatment strategy against established osteosarcoma disease in the lungs.

Spontaneous multiple insufficiency fractures after pelvic abscess and sepsis in a rheumatoid arthritis patient treated with high-load corticosteroid therapy: a case report.

We report the unique occurrence and treatment of spontaneous multiple insufficiency fractures after sepsis in a patient with rheumatoid arthritis (RA). The patient was a 53-year-old woman with a 13-year history of RA. Her disease activity was not influenced by a disease-modifying antirheumatic drug (DMARD) regimen that included bucillamine, D-penicillamine, gold, sulfasalazine, and methotrexate. Due to an increased disease activity, her DMARD treatment regimen was changed to leflunomide. She had also undergone corticosteroid therapy with prednisolone ranging from 10 to 15 mg daily over the previous 8 years. She first presented with a wound infection at the surgical site of resection arthroplasty on her left foot, which had caused hematogenous dissemination that led to pelvic abscess and sepsis. For the next 2 years, she experienced multiple insufficiency fractures in parts of the ilium, sacral body, sacral ala, three thoraco-lumbar vertebral bodies (T12, L1, and L2), and subcapital femoral neck without low energy trauma. Postmenopausal osteoporosis, pelvic abscess, sepsis, decreasing daily activity, high RA disease activity, and high-load corticosteroid therapy were considered to be the causes of these fractures. Nonspecific symptoms such as low back pain and fever delayed diagnosis, which may have led to secondary fractures. Although her course after treatment was satisfactory during the study period, we recommend taking repetitive radiographs to detect insufficiency fracture for RA patients with continuing pain and reducing the corticosteroid dose to prevent infection and fracture.

Extraskeletal Chondroma of the Index Finger: A Case Report.

Extraskeletal chondroma is defined as a rare, benign, cartilaginous tumor arising from soft tissues such as tendons, tendon sheath synovia, and joint capsules with no continuity to the periosteum or bone cortex. In histopathologic findings, the tumor exhibits many lobular structures and some parts similar to hyaline cartilage. Therefore, it is sometimes difficult to differentiate this tumor from low-grade chondrosarcoma because of their similar histopathologic findings. In order to prevent recurrence, it is necessary to remove the tumor as a whole, including the capsule, so as not to leave any remnants of the tumor. In this article, we report our treatment experience with a case of extraskeletal chondroma in the index finger of a 63-year-old patient.

Fibrous Dysplasia with Massive Cartilaginous Differentiation (Fibrocartilaginous Dysplasia) in the Proximal Femur: A Case Report and Review of the Literature.

Fibrous dysplasia (FD) is a monostotic or polyostotic benign bone lesion with spindle-cell proliferation in woven bone and stroma. Rarely, cartilaginous differentiation can be seen in the lesions of FD. FD with massive cartilaginous differentiation is called fibrocartilaginous dysplasia (FCD) and is considered a rare variant of FD. Although pathological findings of FD show irregular immature bone formation without osteoblastic rimming in fibrous tissue, and rarely show very small amounts of cartilage, histological images of FCD are said to show that cartilage with a relatively high cell density is present in the majority and that FD-like findings are seen in parts of it. The most characteristic feature of FCD on images is calcification in the lesions reflecting cartilaginous tissue. On the other hand, typical radiographic findings of FD include shadows with a ground-glass appearance and thinning and bulging of the cortical bone, the observation if calcification is not usual. Therefore, in the diagnosis of FCD, differentiation from multiple enchondromatosis, Ollier disease, chondrosarcoma, and chondrosarcoma secondary to FD is necessary, and it seems important to make a careful diagnosis based not only on the pathological findings but also on imaging and clinical findings. Herein, we report on a case of FD of the proximal femur associated with intralesional extensive carti laginous differentiation in which a pathological fracture occurred during follow-up, with a review of the literature.

Adamantinoma of the distal femur diagnosed 5 years after initial surgery: a case report.

BACKGROUND: Adamantinoma arising in the femur is extremely rare. We report a case of an adamantinoma occurring in the right medial femoral condyle that was diagnosed 5 years after the primary surgery. CASE PRESENTATION: A 74-year-old Asian woman first complained of right knee pain without any cause. Radiographs demonstrated a 4×4.5 cm osteolytic lesion in her medial femoral condyle. Magnetic resonance imaging revealed a lesion which showed low signal on both T1 and T2-weighted image, and enhanced signal with gadolinium contrast administration. She underwent a wide resection of the lesion and was reconstructed with a tumor endoprosthesis. On histological examination, the tumor showed clusters of spindle-shaped and squamoid epithelial cells among the fibrous stroma. Adamantinoma was considered, however, the diagnosis was inconclusive due to the unusual localization and her age. Moreover, it was difficult to exclude metastatic carcinoma. Five years later, she was diagnosed with an abnormal shadow occupying the upper lobe of her right lung in a routine physical examination. She subsequently underwent a resection of the lung mass which histologically showed proliferation of spindle-shaped and squamoid epithelial cells. The histological similarity of the lung tumor and the femoral tumor led to the diagnosis of adamantinoma arising in her right medial femoral condyle with metastasis to the upper lobe of her right lung. CONCLUSION: In this case report, we report the clinical, radiographic, and histological features of an adamantinoma arising in the distal femur with a review of the literature.

Diagnosis of extraskeletal myxoid chondrosarcoma in the thigh using EWSR1-NR4A3 gene fusion: a case report.

BACKGROUND: Extraskeletal myxoid chondrosarcoma is a rare soft tissue sarcoma that has unusual ultrastructural and molecular features. However, unlike other soft tissue sarcomas, it does not have specific clinical symptoms or radiological features, which can make its diagnosis difficult. Nevertheless, extraskeletal myxoid chondrosarcoma has a rare gene fusion (EWSR1-NR4A3) that is useful for making a differential diagnosis. CASE PRESENTATION: A 43-year-old Japanese man presented with a soft tissue mass in his right thigh. A physical examination and radiography revealed a large soft tissue mass. During magnetic resonance imaging, the mass exhibited isointensity on T1-weighted images and high intensity on T2-weighted images, as well as gadolinium enhancement at the side edge of the partition structure. Thus, we considered a possible diagnosis of a malignant myxoid soft tissue tumor, such as myxoid liposarcoma, myxofibrosarcoma, or metastatic carcinomas, including myoepithelial tumor and neuroendocrine tumor, and performed an incisional biopsy to make a definitive diagnosis. The pathological findings revealed a lobulated tumor with a myxoid structure and atypical spindle-shaped cells that created eosinophilic cord-like forms. Immunohistochemistry revealed that the tumor was positive for S-100 and negative for synaptophysin, chromogranin A, and pan keratin (AE1/AE3). The percentage of Ki-67 was 10 % in the hot spot area. Based on these clinicopathological findings, we initially considered the possibility of a myxoid liposarcoma, although we did not observe any lipoblasts. Therefore, we considered the possibility of an extraskeletal myxoid chondrosarcoma. As this tumor is very rare, we searched for the EWSR1-NR4A3 gene fusion using fluorescence in situ hybridization, which confirmed the diagnosis of extraskeletal myxoid chondrosarcoma. Positron emission tomography-computed tomography did not identify any obvious metastases, and we performed radical resection of our patient's vastus medialis and femur with a 3 cm margin. After the resection, we treated his resected femur using liquid nitrogen, and reconstructed his femur using autogenous fibula and plate fixation. No local recurrence or metastasis was observed at the 1-year follow-up. CONCLUSION: Genetic testing is useful for diagnosing extraskeletal myxoid chondrosarcoma based on the presence of the EWSR1-NR4A3 gene fusion.

Hibernoma Showing High Uniform Accumulation on an 18F-Fluorodeoxyglucose Positron Emission Tomography Scan: A Case Report.

BACKGROUND: Hibernoma is a rare, benign, soft tissue tumor arising from brown fat that cannot be distinguished from other lipogenic tumors on computed tomography and magnetic resonance imaging (MRI) scans. On the other hand, the image of hibernoma on 18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) is different from that of other lipogenic tumors. However, fewer studies have investigated the typical features of hibernoma on PET scans. We present the case of a hibernoma that was incidentally detected on 18F-FDG-PET. CASE PRESENTATION: A 48-year-old Asian man underwent 18F-FDG-PET for routine follow-up of gastric cancer. The patient reported a painless soft mass on the upper arm that had persisted for several years. On 18F-FDG-PET, the mass showed a maximum standardized uptake value of 9.6. The mass showed high intensity on T1- and T2-weighted MRI scans, and showed focally enhanced septa after gadolinium administration. The mass was surgically resected. Histopathologically, the mass was composed of brown adipose cells characteristic of hibernoma. His postoperative course was uneventful, and there was no local recurrence at the final 24-month follow-up. CONCLUSION: Hibernoma showed strong uniform accumulation on 18F-FDG-PET, suggesting that 18F-FDG-PET would be a useful modality for the differential diagnosis of hibernoma versus other lipogenic tumors.

Osteoid osteoma of the acetabulum successfully treated with computed tomography-guided resection and ablation using a standard electrosurgical generator: a case report.

BACKGROUND: Osteoid osteoma accounts for approximately 10% of all benign bone tumors. The most common sites of osteoid osteoma are the subcortical shaft and metaphyses of long bones, but any other skeletal bone site can be involved. The acetabulum is a rare site according to past reports. This site presents challenges to optimal management because it is anatomically difficult to approach, and because its rarity leads to limited experience with therapeutic procedures. Here, we report for the first time a rare case of osteoid osteoma in the acetabulum that was successfully treated via resection of the nidus and ablation using a standard electrosurgical generator under computed tomographic guidance. CASE PRESENTATION: A 9-year-old Japanese girl presented at a clinic with left hip pain without apparent cause for 1 month. She was diagnosed as having coxitis simplex. However, her pain did not change for 1 year and she was admitted to another hospital where osteoid osteoma in her left acetabulum was suspected. She was then referred to our hospital approximately 1 year after first symptom presentation, where she presented with severe left hip pain and was completely unable to walk. Computed tomography examinations revealed a well-demarcated 5 mm mass with bone sclerosis in her left acetabulum. The mass was characterized by low intensity on T1 and high intensity on T2 magnetic resonance images. These findings were consistent with osteoid osteoma of left acetabulum. She underwent computed tomography-guided resection of nidus and ablation using a standard electrosurgical generator. A histological examination confirmed acetabular osteoid osteoma. Complete pain relief was achieved after the procedure and she experienced no complications. She could walk without any pain at the final follow-up 1 year post-treatment and no local recurrence was observed. CONCLUSIONS: We successfully treated acetabulum osteoid osteoma without any symptom recurrence by computed tomography-guided resection and ablation using a standard electrosurgical generator. In addition, we preserved our patient's sciatic nerve and triradiate cartilage. Our report provides evidence that a computed tomography-guided procedure should be considered the treatment of choice for osteoid osteoma of the acetabulum because it is a less invasive alternative to en bloc resection.

Langerhans Cell Histiocytosis of the Clavicle in an Adult: A Case Report and Review of the Literature.

Langerhans cell histiocytosis (LCH) usually occurs in children under the age of 10 years with a predilection for the skull, spine, rib and humerus. Solitary LCH occurring in an adult clavicle is uncommon with limited reports to date. The lesion in our patient was curetted with the intent to make a diagnosis, which subsequently lead to the remission of the symptom and the disease. At the final follow-up after 1 year, no local recurrence or metastasis is observed.

Successful Treatment with Pazopanib for Multiple Lung Metastases of Inguinal Epithelioid Sarcoma: A Case Report.

Epithelioid sarcoma is a rare soft tissue sarcoma and usually resistant to chemotherapy. It has high rates of local recurrence and distant metastasis, and the prognosis after metastasis is poor. We report a case of multiple lung metastases of an epithelioid sarcoma originating in the inguinal area that we treated with the multikinase inhibitor pazopanib. The patient was a 38-year-old male who began to experience discomfort in his left inguinal area. Magnetic resonance imaging showed a tumor extended from the medial aspect of the wing of the left ilium along the iliopsoas muscle to its site of insertion on the femur. The histopathological diagnosis with a biopsy was proximal-type epithelioid sarcoma. Although a positron emission tomography examination showed fluorodeoxyglucose accumulation in the left inguinal tumor, there was no distant metastasis. Wide resection by a combined iliac resection procedure was performed. Twelve months after surgery, computed tomography revealed multiple nodules and a diagnosis of bilateral multiple lung metastases was made. Treatment with pazopanib 800 mg was started. After 2.5 months of treatment, a clear reduction in the size of the pulmonary metastases was shown. Thirty months after the start of pazopanib treatment, most of the metastases have disappeared, and no development of new lesions has been seen. Therefore, it appeared that pazopanib was capable of serving as one of the choices of therapeutic agents that should be taken into consideration for the treatment of advanced epithelioid sarcoma.

Computed tomography-guided resection of osteoid osteoma of the sacrum: a case report.

INTRODUCTION: Osteoid osteoma is a benign tumor that usually occurs in the long bones of young adults. Its symptoms can be diverse depending on the location of the tumor and especially difficult to diagnose when occurring in an atypical location. Osteoid osteoma arising in the sacrum is extremely rare, and here, we present a case that was treated successfully in a minimally invasive fashion under computed tomography guidance. CASE PRESENTATION: A 25-year-old Asian man was referred to our institution due to persistent pain in the buttock after 12 months of conservative treatment. Computed tomography and magnetic resonance imaging scans revealed a ring-shaped radiolucency consistent with a nidus of osteoid osteoma in the sacrum. The lesion was subsequently resected under computed tomography guidance and the histological diagnosis was compatible with osteoid osteoma. His postoperative course was uneventful, and at two years after surgery our patient is symptom-free with no evidence of recurrence. CONCLUSIONS: Computed tomography-guided resection of osteoid osteoma in the spinal column is feasible and accurate if there is adequate margin from vital organs. Although rare, it is important to always bear in mind the possibility of osteoid osteoma occurring in the sacrum when no other apparent lesion is detected.

miR-20a encoded by the miR-17-92 cluster increases the metastatic potential of osteosarcoma cells by regulating Fas expression.

The ability of osteosarcoma cells to form lung metastases has been inversely correlated to cell surface Fas expression. Downregulation of Fas allows osteosarcoma cells to circumvent FasL-mediated apoptosis upon entrance into the FasL(+) lung microenvironment. However, the mechanism of Fas regulation remains unclear. Here, we show that miRNA plays a role in the downregulation of Fas expression in osteosarcoma. Expression levels of several members of the miR-17-92 cluster including miR-20a and miR-19a were found to be higher in metastatic low-Fas-expressing LM7 cells than in the parental nonmetastatic high-Fas-expressing SAOS-2 cells. We also found an inverse correlation between Fas and miR-20a expression in all 8 cell lines derived from patient samples. Overexpression of miR-20a consistently resulted in the downregulation of Fas expression in SAOS-2 cells and thus in decreased sensitivity to FasL. Conversely, inhibiting miR-20a in LM7 cells increased Fas expression and their sensitivity to FasL. Mice injected with LM7 stably transfected with anti-miR-20a had fewer metastases than those with control plasmids. Taken together, our findings suggest that miR-20a, encoded by miR-17-92, downregulates Fas expression in osteosarcoma, thus contributing to the metastatic potential of osteosarcoma cells by altering the phenotype and allowing survival in the FasL(+) lung microenvironment.