Juxtacortical chondromyxoid fibroma in the small bones: two cases with unusual location and a literature review.

Chondromyxoid fibroma is a rare bone tumor of cartilaginous origin, representing less than 1% of all bone tumors. It preferentially arises in the eccentric location of the metaphysis of a long tubular bone. Juxtacortical locations are reported infrequently in the long bones and even more rarely in short tubular bones, with only three cases documented. Here we present two new cases of juxtacortical chondromyxoid fibroma in the small bones. One was an intracortical osteolytic lesion of the metatarsal bone of the foot with degenerative atypia that histologically should be differentiated from chondrosarcoma. The other was a phalangeal mass protruding into the interphalangeal joint of the hand, which had been labeled mistakenly as a soft tissue mass preoperatively. These cases illustrated that chondromyxoid fibromas have various the manifestations and should be included in the differential diagnosis of an osteolytic lesion or an exophytic mass in the small bones.

The Efficacy of Radiofrequency Ablation for Bone Tumors Unsuitable for Radical Excision.

BACKGROUND: Bone tumors can cause severe pain and poor quality of life due to recurrence and non-achievement of complete remission after surgery, chemotherapy, or radiotherapy. Radiofrequency ablation (RFA) can be considered for minimally invasive treatment of bone tumors that are difficult to radically excise. In this study, RFA was performed for bone tumors that were difficult to radically excise and did not respond to surgery, chemotherapy, or radiotherapy due to their large sizes and/or locations. The purpose of this study was to retrospectively analyze the clinical characteristics and survival rates of bone tumors after RFA and provide one more treatment option for the future. METHODS: There were 43 patients with bone tumors who underwent percutaneous RFA at our hospital from April 2007 to October 2017. The median age of the patients was 59 years (range, 31-75 years), and the median follow-up duration was 67.2 months (range, 10.2-130.5 months). Of the 43 patients, 26 were male and 17 were female. Thirty-four cases were metastatic bone tumors, 5 were chordomas, 3 were osteosarcomas, and 1 was a giant cell tumor. Pain and functional ability of the patients were evaluated using a visual analog scale (VAS) and the Musculoskeletal Tumor Society (MSTS) functional scoring system, respectively. Scores were recorded preoperatively, 1 week postoperatively, and 4 weeks postoperatively. The 1-year, 2-year, and 5-year survival rates were evaluated using the Kaplan-Meier method. RESULTS: The mean VAS score was 8.21 preoperatively. The mean VAS score at 1 week, 4 weeks, 12 weeks, and 24 weeks postoperatively were 3.91, 3.67, 3.31, and 3.12, respectively. The mean preoperative MSTS score was 64.0% (range, 32%-87%). The mean postoperative MSTS score was 71.0% (range, 40%-90%). The 1-year, 2-year, and 5-year survival rates were 95.3%, 69.8%, and 30.2%, respectively. CONCLUSIONS: As per our study findings, RFA was effective in reducing pain and improving functional ability of patients with bone tumors that were difficult to radically excise.

Evaluation of immune-biomarker expression in high-grade soft-tissue sarcoma: HLA-DQA1 expression as a prognostic marker.

High-grade soft-tissue sarcoma (STS) is a highly malignant neoplasm with a poor overall prognosis. Numerous prognostic factors determine tumor progression and patient outcomes. Various immune-associated cells identified in the tumor microenvironment have important roles in various tumor types. The present study was performed to evaluate the expression of immune-associated genes and to elucidate the association between these genes and the prognosis in high-grade STS. A total of 12 formalin-fixed, paraffin-embedded tissue samples of high-grade STS were subjected to gene expression analysis using the NanoString nCounter® System and another 35 samples were used for immunohistochemistry. For comparative analysis, the patients were divided into two groups according to overall survival (OS). The expression levels of 770 genes were first analyzed using the nCounter® PanCancer Immune Profiling Panel. Immunohistochemistry was then performed for the most significantly altered genes. Subsequently, the association between gene expression and prognosis of high-grade STS was evaluated. Of the 770 immune-associated genes analyzed, several genes were identified as being differentially expressed between the two groups. Based on gene expression levels and fold change, 13 representative genes were identified; 7 of the 13 candidate genes (C3, CD36, DOCK9, FCER2, FOS, HLA-DRB4 and NCAM1) were significantly overexpressed in the poor prognosis group, while the other 6 immune-associated genes (BIRC5, DUSP4, FOXP3, HLA-DQA1, HLA-DQB1 and LAG3) were increased in the good prognosis group. By immunohistochemistry, the expression of the 13 immune-associated genes was confirmed to be significantly different between the two groups. Expression of HLA-DQA1, HLA-DQB1 and HLA-DRB4 was observed in 74.3, 34.3 and 48.6% of tumors, respectively. HLA-DQA1 and HLA-DQB1 were significantly decreased, whereas HLA-DRB4 was significantly increased in the poor prognosis group. Of note, expression of HLA-DQA1 was associated with a significantly longer OS (P=0.028). In conclusion, HLA-DQA1 expression was significantly associated with long-term survival and may therefore be an immune biomarker for good prognosis in high-grade STS.

Correlation between anterior thigh pain and morphometric mismatch of femoral stem.

BACKGROUND: Postoperative pain occurring after hip arthroplasty has become common since the expanded use of cementless femoral stems. The characteristic pain develop in the anterolateral thigh area. This study aimed to predict anterior thigh pain based on the measurements of postoperative anteroposterior (AP) and lateral (Lat) radiographs of the hip joint. METHODS: The present study included 26 patients (29 hips) who underwent total hip replacement or bipolar hemiarthroplasty between March 2010 and May 2016, whose complete clinical information was available. AP and Lat radiographs of the affected hip were taken on the day of surgery and 1 and 6 months postoperatively. Patients with improper radiographs were excluded. The distance from the femoral stem to the nearest cortical bone in the distal region of the stem was measured. The patient group with a visual analog scale (VAS) score of ≥6 points was designated as patients with anterior thigh pain. RESULTS: Sex, age, weight, height, body mass index, and bone mineral density in the lumbar spine and femur did not have a significant effect on postoperative VAS scores (p>0.05). Presence of contact between the femoral stem and cortical bone was associated with postoperative anterior thigh pain. CONCLUSION: Hip AP and Lat radiographs are usually taken to confirm fixation and alignment of the femoral stem after hip arthroplasty. The measurement method introduced in this study can be utilized for predicting anterior thigh pain after hip arthroplasty.

Clinical Outcome of Beta-Tricalcium Phosphate Use for Bone Defects after Operative Treatment of Benign Tumors.

BACKGROUND: We investigated the clinical outcome in patients whose cavitary bone defects were treated with beta-tricalcium phosphate (ß-TCP) after surgical removal of benign tumors. METHODS: Between March 2015 and December 2015, 20 patients who underwent operation for bone tumors were enrolled into this study and prospectively followed up for a median period of 28.1 months. RESULTS: When the radiographic sign of complete resorption was defined as greater than 50% resorption of the allograft material accompanied by bone remodeling until 12 months, 55% of patients had complete resorption. Positive correlation between the filling volume and time needed for complete resorption was not found (p = 0.184). CONCLUSIONS: Purified ß-TCP could be a suitable choice as a bone graft substitute after the removal of benign bone tumors.

Resection arthroplasty in radiation-induced osteonecrosis of the hip.

PURPOSE: The purpose of this study was to evaluate the choice of appropriate surgical procedure through follow-up of postoperative results in patients with radiation-induced osteonecrosis of the hip. MATERIALS AND METHODS: From January 1990 to December 2010, 25 patients underwent surgery for hip osteonecrosis after pelvic irradiation, for a total of 31 cases. The mean patient age was 61.6 years and the mean follow-up period was 60.4 months. There were 28 cases of primary total hip arthroplasty, three cases of primary resection arthroplasty, and six cases of secondary resection arthroplasty after total hip arthroplasty failure. The THA group was classified into two groups according to the period of operation: 1990 ∼ 2000 and 2001 ∼ 2010. THA and resection arthroplasty were compared retrospectively. RESULTS: In the 16 cases of primary total hip arthroplasty (1990 ∼ 2000), 8 cases (50%) had a failed acetabular component. In 12 cases of primary total hip arthroplasty (2001 ∼ 2010), two cases (16.7%) had a failed acetabular component and two cases (16.7%) had an infection. Six cases underwent resection arthroplasty after total hip arthroplasty. There were no complications in the nine cases of resection arthroplasty. Seven of the nine cases (77.7%) had pain relief. The mean VAS scores of the resection arthroplasty group were lower than those of the total hip arthroplasty group at the time of the latest follow up (P = 0.04). CONCLUSIONS: The failure rate of total hip arthroplasty used in radiation necrosis has decreased. Therefore, total hip arthroplasty should be the primary surgical method in patients with radiation-induced osteonecrosis of the hip. Resection arthroplasty is limited as first-line therapy due to functional problems. It use should be limited to pain control in low-demand elderly patients.

Correlation of IGF1R expression with ABCG2 and CD44 expressions in human osteosarcoma.

Osteosarcoma is the most common type of malignant bone tumors. Insulin Growth Factor 1 receptor (IGFR1) has been known as a prognostic factor for metastasis of osteosarcoma. ABC subfamily G member2 (ABCG2) is related to resistance to anti-cancer drug, and CD44 has a role in tumor growth and metastasis. The purpose of this study is to investigate the relationship among expression patterns of IGF1R, ABCG2, and CD44 in osteosarcoma. The expression levels of IGF1R, ABCG2, and CD44 proteins were determined in tissue arrays containing osteosarcoma tissues from 59 osteosarcoma patients. The expression pattern of IGF1R was highly correlated with the expression pattern of ABCG2 (r = 0.88) in overall osteosarcoma patients. According to pathological types, the expression pattern of IGF1R showed the higher correlation with ABGC2 (r = 0.90) and CD44 (r = 0.61) in osteoblatic type than in chondroblastic type. According to gender with pathologic type, the correlation between the expression patterns of IGF1R and CD44 was higher in male with osteoblatic type than in female with osteoblatic type. Among different age groups, the 1-10 years age group showed higher correlation in IGF1R versus CD44 (r = 0.90) and ABCG2 versus CD44 (0.80) than in other age groups. These results showed that the expression of IGF1R appears to be highly correlated with the expression of ABCG2 in osteosarcoma and with the expression of CD44 in osteosarcoma patients under age of 10, which suggests that ABCG2 and CD44 can be used as prognostic factors with IGF1R for specific prognosis and efficient treatment of osteosarcoma.

Intraosseous Lipoma: 18 Years of Experience at a Single Institution.

BACKGROUND: Intraosseous lipoma is a very rare lesion that constitutes no more than 0.1% of all bone tumors. We analyzed 21 cases of intraosseous lipoma at a single institution for clinical and radiographic characteristics. METHODS: A retrospective study was performed on 21 pathologically confirmed intraosseous lipomas treated in our hospital from 2000 to 2017. Simple X-ray and magnetic resonance imaging findings and medical records were reviewed. Patients' age, sex, and clinical symptoms were investigated. From the radiographic images, the site of the lesion, calcification, bony expansion, and stage of the lesion were evaluated. Correlations between the degree of involution and clinical symptoms were analyzed. RESULTS: The mean age of patients was 50 years (range, 20 to 67 years), and there were 13 males and eight females. The mean lesion size was 6.1 cm (range, 2.5 to 13.6 cm). The most common anatomical site of the lesion was the femur (seven cases), and three cases occurred in flat bones such as the ilium and scapula. Visual analogue scale score for pain was 3 to 6 in 15 patients. There were no complaints of functional limitation. There was no correlation between the degree of degeneration and clinical symptoms (p = 1.000). Curettage was performed as a surgical treatment in 20 patients, and bone graft was performed using a bone chip. Excision was performed in one patient. Pain was resolved in seven of 11 patients with a complaint of preoperative pain; intermittent pain remained in four cases. There was no local recurrence or malignant change during the follow-up. CONCLUSIONS: There was no correlation between the degree of degeneration and clinical symptoms. Pain was the most common clinical symptom, but it was rarely accompanied by functional limitation. However, it is important to distinguish it from other pain-inducing disorders. The incidence of intraosseous lipomas is low, and detection based on various imaging findings can be difficult. Clear understanding of the radiographic findings and symptoms of intraosseous lipoma is helpful for diagnosis and differentiation.

The effect of bone morphogenetic protein-2 on osteosarcoma metastasis.

PURPOSE: Bone Morphogenetic Protein-2 (BMP-2) may offer the potential to enhance allograft-host osseous union in limb-salvage surgery following osteosarcoma resection. However, there is concern regarding the effect of locally applied BMP-2 on tumor recurrence and metastasis. The purpose of this project was to evaluate the effect of exogenous BMP-2 on osteosarcoma migration and invasion across a panel of tumor cell lines in vitro and to characterize the effect of BMP-2 on pulmonary osteosarcoma metastasis within a xenograft model. EXPERIMENTAL DESIGN: The effect of BMP-2 on in vitro tumor growth and development was assessed across multiple standard and patient-derived xenograft osteosarcoma cell lines. Tumor migration capacity, invasion, and cell proliferation were characterized. In addition, the effect on metastasis was measured using a xenograft model following tail-vein injection. The effect of exogenous BMP-2 on the development of metastases was measured following both single and multiple BMP-2 administrations. RESULTS: There was no significant difference in migration capacity, invasion, or cell proliferation between the BMP-2 treated and the untreated osteosarcoma cell lines. There was no significant difference in pulmonary metastases between either the single-dose or multi-dose BMP-2 treated animals and the untreated control animals. CONCLUSIONS: In the model systems tested, the addition of BMP-2 does not increase osteosarcoma proliferation, migration, invasion, or metastasis to the lungs.

Clinical Usefulness of Long-term Application of Fentanyl Matrix in Chronic Non-Cancer Pain: Improvement of Pain and Physical and Emotional Functions.

BACKGROUND: Opioids are recently recommended for those who do not gain adequate pain relief from the use of acetaminophen or nonsteroidal anti-inflammatory drugs. Medical opioids are administered in various routes, and transdermal opioid products that can make up for the weaknesses of the oral or intravenous products have been developed. This study is to evaluate the clinical usefulness of fentanyl matrix in terms of the long-term improvement in pain and physical and mental functions. METHODS: This was a multicenter, open, prospective, observational study that was conducted in 54 institutions in Korea. Patients with non-cancerous chronic pain completed questionnaires, and investigators also completed questionnaires. A total of 1,355 subjects participated in this study, and 639 subjects completed the study. Subjects received transdermal fentanyl matrix (12 µg/hr, 25 µg/hr, or 50 µg/hr depending on the patient's response and demand). Subjects visited at 29 ± 7 days, 85 ± 14 days, and 169 ± 14 days after administration, respectively, to receive drug titration and fill out the questionnaires. The results were analyzed using the intention-to-treat (ITT) analysis, full analysis set (FAS), and per-protocol (PP) analysis. The FAS analysis included only 451 participants; the PP analysis, 160 participants; and the ITT analysis, 1,355 participants. RESULTS: The intensity of pain measured by the Numeric Rating Scale decreased from 7.07 ± 1.78 to 4.93 ± 2.42. The physical assessment score and mental assessment score of the Short-Form Health Survey 12 improved from 28.94 ± 7.23 to 35.90 ± 10.25 and from 35.80 ± 11.76 to 42.52 ± 10.58, respectively. These differences were significant, and all the other indicators also showed improvement. Adverse events with an incidence of ≥ 1% were nausea, dizziness, vomiting, and pruritus. CONCLUSIONS: The long-term administration of fentanyl matrix in patients with non-cancerous pain can reduce the intensity of pain and significantly improves activities of daily living and physical and mental capabilities.

Temporary hemiarthroplasty with a synthetic device in children with osteosarcoma around the knee as a bridging procedure until skeletal maturity.

BACKGROUND: We hypothesized that hemiarthroplasty with a synthetic device in skeletally immature patients with osteosarcoma around the knee would be functional due to high adaptability in the pediatric age group, and may decrease the number of surgeries until limb equalization by preserving the nearby physis. METHODS: We analyzed the outcomes of 25 hemiarthroplasties (12 distal femur, 13 proximal tibia). Average patient age was 11.8 years. We assessed (1) whether hemiarthroplasty could be considered as a viable option and could preserve growth of the nearby physis, and (2) whether these patients could reach the final goal of adult-type tumor prosthesis implantation within a preplanned number of surgeries. RESULTS: Three (12%) of 25 hemiarthroplasties showed failure. Average Musculoskeletal Tumor Society functional score of 23 patients was 25.1. Average tibial and femoral shortening for the corresponding reconstruction was 0.3 cm and 0.5 cm, respectively. In terms of number of surgeries for limb equalization, 19 patients (76%) had less, four (16%) had equal, and two (8%) had more surgeries than planned. CONCLUSIONS: Hemiarthroplasty is a sound option until skeletal maturity, allowing surgeons to choose the appropriate procedure based on the patient's growth status, and may reduce the amount of shortening by preserving nearby physis.

Osteosarcoma in Asian Populations Over the Age of 40 Years: A Multicenter Study.

BACKGROUND: Elderly patients with osteosarcoma (OSA) are no longer uncommon; however, many questions remain regarding this population. We investigated the clinicopathological characteristics and prognostic factors of OSA in an Asian population over the age of 40 years. METHODS: This was a multi-national, multi-institutional study by the Eastern Asian Musculoskeletal Oncology Group (EAMOG). RESULTS: A total of 232 patients were enrolled (116 males and 116 females), with a median age of 50 years at diagnosis; 25 (10.8 %) patients exhibited initial metastasis. Median follow-up was 52 months for survivors. We observed 102 osteolytic and mixed radiographic findings for 173 lesions. Histological subtypes other than osteoblastic type were frequent. Radiation-associated OSA was seen in seven patients, with a 5-year overall survival (OS) of 16.7 %. No Paget's OSA was observed. High-grade spinopelvic OSA was seen in 29 (12.5 %) patients. The 5-year OS was 59.4 % in patients without initial metastasis and 45.2 % in patients with spinopelvic OSA. While surgery and initial metastasis were common prognostic factors for OS, chemotherapy was not. Histologic response to neoadjuvant chemotherapy was poor in 61 of 83 patients. CONCLUSION: This study revealed distinct clinicopathological features of OSA patients over 40 years of age compared with younger patients, such as the high incidence of axial tumors, common osteolytic and mixed radiographic findings, the high frequency of unusual histologic subtypes, and poor prognosis. Contrary to Western elderly patients with OSA, there was no Paget's OSA in this study, which may result in a lower incidence of secondary OSA. Prognostic factor analyses demonstrated chemotherapy did not influence OS.

The analysis of treatment of aggressive fibromatosis using oral methotrexate chemotherapy.

BACKGROUND: Aggressive fibromatosis is a rare but invasive tumor infiltrating widely between fascia and muscle fibers. It has a high tendency to be locally recurrent despite complete resection. Effectiveness of adjuvant treatment for aggressive fibromatosis including radiotherapy, pharmacological agents, hormonal treatments, and chemotherapy have been previously reported. The purpose of this article was to collect and analyze all information regarding the effectiveness and side effects of oral methotrexate in aggressive fibromatosis. METHODS: From 2005 to 2011, eleven patients with aggressive fibromatosis treated with oral methotrexate at our institution were analyzed in this study. Oral methotrexate was administered once per week at 10 mg per week. Authors collected information about effectiveness concerning cases of local recurrence and metastasis. RESULTS: Eleven patients had remission, two patients had local recurrence. Fatal complications or toxicity were not observed. CONCLUSIONS: Oral methotrexate given at this dose and schedule was considered as a useful treatment in primary inoperable fibromatosis and recurrent fibromatosis.

Tumor treated by endoscopy.

BACKGROUND: This study was conducted to examine the clinical usefulness and efficacy of endoscopic curettage on benign bone tumor. METHODS: Thirty-two patients (20 men and 12 women) with benign bone tumor were included in the study. The patients were aged between five and 76 years; the mean follow-up period was 27.05 months (range, 9.6 to 39.9 months). The primary sites include simple bone cyst (9 cases), fibrous dysplasia (6 cases), enchondroma (5 cases), non-ossifying fibroma (4 cases), bone infarct (3 cases), aneurysmal bone cyst (1 case), chondroblastoma (1 case), osteoblastoma (1 case), intraosseous lipoma (1 case), and Brodie abscess (1 case). A plain radiography was performed to assess the radiological recovery. Radiological outcomes, including local recurrence and bone union, were evaluated as excellent, good, poor, and recurred. RESULTS: In our series, there were 27 cases (84.4%) of good or better outcomes, six cases (18.8%) of complications (4 local recurrence, 1 wound infection, and 1 pathologic fracture). CONCLUSIONS: Our results showed that endoscopic curettage and bone graft had a lower rate of recurrence and a higher cure rate in cases of benign bone tumor. It can, therefore, be concluded that endoscopic curettage and bone graft might be good treatment modalities for benign bone tumors.

ß-Catenin Does Not Confer Tumorigenicity When Introduced into Partially Transformed Human Mesenchymal Stem Cells.

Although osteosarcoma is the most common primary malignant bone tumor in children and adolescents, its cell of origin and the genetic alterations are unclear. Previous studies have shown that serially introducing hTERT, SV40 large TAg, and H-Ras transforms human mesenchymal stem cells into two distinct sarcomas cell populations, but they do not form osteoid. In this study, ß-catenin was introduced into mesenchymal stem cells already containing hTERT and SV40 large TAg to analyze if this resulted in a model which more closely recapitulated osteosarcoma. Results. Regardless of the level of induced ß-catenin expression in the stable transfectants, there were no marked differences induced in their phenotype or invasion and migration capacity. Perhaps more importantly, none of them formed tumors when injected into immunocompromised mice. Moreover, the resulting transformed cells could be induced to osteogenic and chondrogenic differentiation but not to adipogenic differentiation. Conclusions. ß-catenin, although fostering osteogenic differentiation, does not induce the malignant features and tumorigenicity conveyed by oncogenic H-RAS when introduced into partly transformed mesenchymal stem cells. This may have implications for the role of ß-catenin in osteosarcoma pathogenesis. It also may suggest that adipogenesis is an earlier branch point than osteogenesis and chondrogenesis in normal mesenchymal differentiation.

Long-term survivals of stage IIb osteosarcoma: a 20-year experience in a single institution.

BACKGROUND: The purpose of this study is to evaluate the disease-free survival (DFS) and overall survival (OS) of patients with stage IIB osteosarcoma at a single institution for 20 years and to compare the results according to the chemotherapy protocols. METHODS: From Jan 1988 to Nov 2008, 167 patients with osteosarcoma were treated at our hospital and among them, 117 patients (67 males and 50 females) with stage IIB osteosarcoma were evaluable. Their mean age was 22.6 years (range, 8 months to 71 years). Seventy-eight cases underwent the modified T10 (M-T10) protocol (group 1), 23 cases underwent the T20 protocol (group 2) and 16 cases underwent the T12 protocol (group 3). The DFS and OS were calculated and compared according to the chemotherapy protocols. RESULTS: At a mean follow-up of 78.9 months, 63 patients were continuously disease-free (63/117), 6 patients were alive after having metastatic lesions, 7 patients died of other cause and 41 patients died of their disease. The 5- and 10-year OS rates were 60.2% and 44.8%, respectively and the 5- and 10-year DFS rates were 53.5% and 41.4%, respectively. There was no significant difference of the OS and DFS between the chemotherapy protocols (p = 0.692, p = 0.113). CONCLUSIONS: At present, we achieved success rates close to the internationally accepted DFS and OS. We were able to achieve the higher survival rates using the M-T10 protocol over the 20 years. However, there was no significant difference of results between the chemotherapy protocols. We think the M-T10 protocol will achieve more favorable results in the near future.

A reconstruction with extracorporeal irradiated autograft in osteosarcoma around the knee.

BACKGROUND AND OBJECTIVES: An extracorporeal irradiated (ECI) autograft was first reported in Israel in 1968 for the treatment of primary malignant bone tumor. However, subsequent reports covered mostly short-term follow up results, and the reported results of reconstruction vary from study to study. We analyze the long-term follow up results of reconstruction using an extracorporeal irradiated (ECI) autograft in osteosarcoma around the knee. METHODS: We retrospectively reviewed 23 osteosarcoma patients who underwent reconstruction with ECI between December 1995 and April 2005. The 15 males and 8 females had a mean age of 21 years (range: 7-74) and a mean follow-up of 127 months(range: 57-170). Tumors were located in the distal femur in 14 cases, and the proximal tibia in 9 cases. Pathological types were conventional in 22 cases, and parosteal in 1 case. Resection methods were osteoarticular in 18 cases and total joint in 5 cases. Eighteen cases were reconstructed with the ECI autograft and five with ECI autograft-prosthesis composite (APC). The Musculoskeletal Tumor Society (MSTS) score was used for functional evaluation. The overall survival rate, local recurrence, complications were analyzed. RESULTS: The overall survival rate was 82.6%, and the disease-free survival rate was 69.5%. We found 20 complications, including 6 nonunions, 5 deep infections, 4 joint instabilities, 2 fractures, 1 limb-length discrepancy (LLD), 1 epiphyseal collapse, and 1 vessel occlusion. The average MSTS functional score was 62.6%. CONCLUSIONS: Reconstruction with an extracorporeal irradiated is not recommended for osteosarcoma around the knee.

A 9-month-old phosphaturic mesenchymal tumor mimicking the intractable rickets.

Phosphaturic mesenchymal tumor is an extremely rare disease and is frequently associated with oncogenic osteomalacia showing paraneoplastic syndrome, which is characterized by phosphaturia, hypophosphatemia, normocalcemia, and decreased levels of 1,25-dihydroxyvitamin D3 associated with a tumor. A 2-year-old boy, who had a soft tissue tumor on his right thigh and previously diagnosed as myositis ossificans at 9-months-old, was presented with rachitic rosary and mildly enlarged tumor. Biochemical investigations showed hypophosphatemia, hyperphosphaturia, and an increased alkaline phosphatase level of 440 U/l (25-100 U/l), suggesting rickets, which was resistant to vitamin D dietary supplementation. We were certain of intractable rickets because of oncogenic hypophosphatemia and thus decided to excise the soft tissue mass. We observed laboratory improvement of rickets after 2 weeks. On the basis of surgical and histopathological examinations, the tumor was finally diagnosed as the phosphaturic mesenchymal tumor.

Osteosarcoma of the patella: biologic reconstruction with allograft.

Osteosarcoma rarely occurs in the patella. The majority of lesions located in the patella are usually benign. According to the literature, osteosarcoma of the patella has been reported in 32 cases. Surgical treatment (patellectomy, resection and arthrodesis with allograft, and total joint replacement) was attempted in several cases, but neither function of the knee joint nor prognosis of the patients were good. A 53-year-old woman reported pain and swelling in the left knee. Based on plain radiographs and magnetic resonance imaging (MRI), a bone tumor was suspected, and an open bone biopsy of the patella was performed. The pathologic diagnosis was osteoblastic osteosarcoma. A total patellectomy was performed because MRI showed a lesion that did not spread into the joint. A reconstruction was subsequently performed by allograft patella. The graft consisted of a quadriceps tendon, a patella with a patellar tendon, and the medial and lateral retinacula. Twenty-six months postoperatively, the function of the knee joint was almost similar to that before the procedure, and there was no evidence of recurrence or metastasis. After the procedure, the patient could walk without pain and the knee joint could flex to 140 degrees with extension lag of 10 degrees . To our knowledge, this is the first report of a biologic reconstruction with allograft patella after total patellectomy in osteosarcoma involving the patella.

Prognostic effect of diaphyseal location in osteosarcoma: a cohort case-control study at a single institute.

BACKGROUND: Little is known about the clinical outcome or prognosis of diaphyseal osteosarcoma treated with modern therapeutic strategies. METHODS: We conducted both cohort (n=400) and case-control (n=102) studies on 34 American Joint Committee on Cancer stage II diaphyseal osteosarcomas of the extremities. RESULTS: In the cohort study, 34 patients with a diaphyseal osteosarcoma showed significantly better survival than 366 patients with metaphyseal osteosarcoma (5-year metastasis-free survival rates, 87% for cases vs. 59% for controls, P=0.01; 5-year overall survival rates, 90% for cases vs. 71% for controls, P=0.04). The case-control study conducted on 34 patients with diaphyseal osteosarcoma and 68 controls (recruited from among the 366 patients with metaphyseal osteosarcoma by matching for age, tumor volume, and location) showed no survival difference between cases and controls (5-year metastasis- free survival rates, P=0.07; 5-year overall survival rates, P=0.26). CONCLUSIONS: Location differences between the diaphysis and metaphysis may have no prognostic relevance.