Synovial sarcomas (SS) represent a unique subset of soft tissue sarcomas (STS) and account for 5–10% of all STS. Synovial sarcoma differs from other STS by the relatively young age at diagnosis and clinical presentation. Synovial sarcomas have unique genomic characteristics and are driven by a pathognomonic t(X;18) chromosomal translocation and subsequent formation of the SS18:SSX fusion oncogenes. Similar to other STS, diagnosis can be obtained from a combination of history, physical examination, magnetic resonance imaging, biopsy and subsequent pathology, immunohistochemistry and molecular analysis. Increasing size, age and tumor grade have been demonstrated to be negative predictive factors for both local disease recurrence and metastasis. Wide surgical excision remains the standard of care for definitive treatment with adjuvant radiation utilized for larger and deeper lesions. There remains controversy surrounding the role of chemotherapy in the treatment of SS and there appears to be survival benefit in certain populations. As the understanding of the molecular and immunologic characteristics of SS evolve, several potential systematic therapies have been proposed.

Limb salvage surgery (LSS) with endoprosthetic replacement is the most common method of reconstruction following bone tumor resection in the adult population. The risk of a postoperative infection developing is high when compared with conventional arthroplasty and there are no appropriate guidelines for antibiotic prophylaxis. We sought to answer the following questions: (1) What is the overall risk of deep infection and the causative organism in lower-extremity long-bone tumor surgery with endoprosthetic reconstruction? (2) What antibiotic regimens are used with endoprosthetic reconstruction? (3) Is there a correlation between infection and either duration of postoperative antibiotics or sample size? We conducted a systematic review of the literature for clinical studies that reported infection rates in adults with primary bony malignancies of the lower extremity treated with surgery and endoprosthetic reconstruction. The search included articles published in English between 1980 and July 2011. The systematic literature review yielded 48 studies reporting on a total of 4838 patients. The overall pooled weighted infection rate for lower-extremity LSS with endoprosthetic reconstruction was approximately 10% (95% CI, 8%–11%), with the most common causative organism reported to be Gram-positive bacteria in the majority of cases. The pooled weighted infection rate was 13% after short-term postoperative antibiotics and 8% after long-term postoperative antibiotics. There was no correlation between sample size and infection rate. Infection rates of 10% are high when compared with rates for conventional arthroplasty. Our results suggest that long-term antibiotic prophylaxis decreases the risk of deep infection. However, the data should be interpreted with caution owing to the retrospective nature of the studies.

Giant cell tumor of bone is a primary bone tumor that is treated surgically and is associated with high morbidity in many cases. This tumor consists of giant cells expressing RANK (receptor activator of nuclear factor-κB) and mesenchymal spindle-like stromal cells expressing RANKL (RANK ligand); the interaction of these cells leads to bone resorption. Denosumab is a monoclonal antibody that binds RANKL and directly inhibits osteoclastogenesis. Clinical studies have suggested clinical and histological improvement when denosumab was administered to patients with a giant cell tumor. However, no studies have yet examined the viability and functional characteristics of tumor cells following denosumab treatment. Specimens were obtained from six patients with a histologically confirmed giant cell tumor. Two of the patients had been treated with denosumab for six months. Primary cultures of stromal cells from fresh tumor tissue were established. Cell proliferation was measured over a two-day time course. The expression of RANKL and osteoprotegerin was analyzed with use of real-time PCR (polymerase chain reaction). Histological specimens from both patients who had completed denosumab treatment showed the absence of giant cells but persistence of stromal cells. Cell proliferation studies indicated that proliferation of stromal cells cultured from clinical specimens following denosumab treatment was approximately 50% slower than that of specimens from untreated patients. The expression of RANKL in the specimens from the treated patients was almost completely eliminated. Once the giant cell tumor tissue was no longer exposed to denosumab, the stromal cells continued to proliferate in vitro, albeit to a lesser degree. However, they also showed almost complete loss of RANKL expression. It is clear that treatment with denosumab only partially addresses the therapeutic need of patients with a giant cell tumor by wiping out the osteoclasts but leaving the neoplastic stromal cells proliferative.

Chondrosarcomas are a diverse group of malignant cartilaginous matrix-producing neoplasms. Conventional chondrosarcomas are a continuum of disease based on the biologic activity of the tumor. The tumors range from the relatively biologically benign low-grade tumors or intermediate atypical cartilaginous tumors (ACTs), to malignant, aggressive high-grade tumors. The clinical presentation, radiographic and pathologic findings, treatments and outcomes vary significantly based on the histologic grade of the tumor. Chondrosarcomas present a diagnostic dilemma, particularly in the differentiation between high- and intermediate-grade tumors and that of low-grade tumors from benign enchondromas. A multidisciplinary team at a tertiary sarcoma centre allows for optimal care of these patients.