Besides conventional chondrosarcoma, several rare chondrosarcoma subtypes are described, comprising about 15% of all chondrosarcomas. Clear cell chondrosarcoma (CCS) is a low-grade malignant tumour, often recurring after curettage, and showing overall survival of about 85%. Mesenchymal chondrosarcoma (MCS) is a highly malignant tumour occurring in bone and soft tissue of relatively young patients. The tumour shows differentiated cartilage mixed with undifferentiated small round cells. It often metastasises and shows a 5-year overall survival of 55%. Dedifferentiated chondrosarcoma (DDCS) is a tumour containing a high-grade non-cartilaginous sarcoma (DD), and a usually low-grade malignant cartilage-forming tumour (WD).

The prognosis is poor. The lack of efficacious treatment of these rare tumours emphasises the need to learn more about their characteristics and to unravel potential targets for therapy.

We constructed tissue microarrays (TMAs) with 2mm cores of 45 DDCS (WD and DD), 24 CCS, and 25 MCS, in triplicate.

Using immunohistochemistry, we investigated protein expression of estrogen-signaling molecules, growth plate-signaling molecules, and other molecules which might be potential targets for therapy. In addition, we gathered genomic information using Agilent 44K oligo arrays.

30% of the WD components were positive for Cox-2. Almost all others were negative. For Bcl2, 88% of the small cells and 32% of the cartilage in MCS were positive. In CCS, WD, and DD 48%, 4%, and 12% were positive, respectively. We demonstrated the presence of ESR1 and aromatase protein in the majority of tumours in all subtypes. Using array CGH, we observed similar aberrations in the two components of DDCS, with additional aberrations in the DD.

Celecoxib treatment is not recommended, as most of the tumours are negative for Cox-2. However, the presence of ESR1 and aromatase support a possible effect of anti-estrogen treatment in all subtypes, and application of Bcl2 inhibitors might chemosensitise MCS.

Aim

Assess the oncological and clinical outcomes associated with intralesional curettage, phenol and bone grafting of the lesions.

Aim

To report late development of sarcomas on sites of previously curetted and grafted benign tumours. Rare cases of development of sarcomas in sites of previous benign lesions are documented, and the development is generally considered secondary to progression of benign lesions, even without radiotherapy.

Introduction: Giant cell tumour of bone (GCTB) is an expansile osteolytic tumour of bone which contains numerous osteoclast-like giant cells. GCTB is a locally aggressive tumour which can cause extensive bone destruction that can be difficult to control surgically, up to 35% of cases recurring after simple curettage. Bisphosphonates are anti-resorptive agents that have proved effective in the treatment of a number of osteolytic conditions.

Methods: This study reports results from four European centres where bisphosphonates are being used to treat problematic GCTBs. Details of treatment with bisphosphonates of 25 cases of primary, recurrent and metastatic GCTBs was assessed clinically and radiologically.

Results: Most primary/recurrent tumours did not exhibit progressive enlargement and, in some cases, both primary and metastatic GCTBs showed a degree of radiological improvement following treatment. Some patients also noted relief of pain following treatment. In a few cases, no apparent treatment effect was noted and there was disease progression. Several inoperable large spinal/pelvic GCTBs remained stable in size following treatment.

Discussion: Our findings provide preliminary evidence for the use of bisphosphonates to inhibit the progressive osteolysis associated with GCTB. These agents had a beneficial clinical and/or radiological effect in most cases. This study reports results from four European centres and highlights the fact that these centres are all employing different clinical indications and different regimes of bisphosphonate treatment. Bisphosphonates have significant side effects and indications for treatment and standardisation of drug type and dosage regimes (and measurement of agreed outcome measures to determine treatment efficacy) should be established for the use of these agents to control GCTB tumour growth and osteolysis.

Current 5-year survival after complete resection of pulmonary metastases is ≈ 30%, and many patients develop pulmonary recurrences. Obviously new treatment options are needed for this indication. Isolated lung perfusion (ILuP) is an experimental technique to deliver high-dose chemotherapy to the lung without systemic exposure. Recently, a phase I trial of ILuP combining 45 mg melphalan followed by pulmonary metastasectomy for resectable lung metastases proved to be feasible and safe.

The current 3-center phase II study (including University Hospital Antwerp/P. van Schil and Anthonius Hospital Nieuwegein/F. Schramel) allows patients with resectable lung metastases from colorectal cancer, soft tissue- and osteosarcoma to be treated with ILuP prior to metastasecomy.

At Leiden University Medical Center we treated 8 patients: 4 with colorectal cancer (age 54–59 y), 2 osteosarcoma (19–20 y), 1 sarcoma NOS of bone (38 y) and 1 sarcoma NOS (56 y) of soft tissue. The number of metastases was 1–2 and one patient had resection of 9 metastases. The procedure was uncomplicated in 7 cases and 1 patient had reversible pulmonary edema. Hospital admission duration was 6–8 days in the uncomplicated group and 14 days in the one patient with a complication. No long term toxicity was observed with extensive follow-up including lung function tests. With a median follow-up of 7 months (range 2–16), only the patient with 9 metastases had a recurrence and died of disease.

Our single center prelimininary data show that ILuP is feasible and does not lead to irreversible or severe toxicity. Compared to retrospective data with metastasectomy alone, perfusion did not add toxicity. Follow-up is too short to draw any conclusions on efficacy.

Giant cell tumour of bone (GCTB) is an expansile osteolytic tumour of bone which contains numerous osteoclast-like giant cells. GCTB is a locally aggressive tumour which can cause extensive bone destruction that can be difficult to control surgically, up to 35% of cases recurring after simple curettage. Bisphosphonates are anti-resorptive agents that have proved effective in the treatment of a number of osteolytic conditions.

In keeping with its known effect on osteoclasts, we found that the aminobisphosphonate zoledronate abolished in vitro lacunar resorption in cultures of osteoclasts isolated from GCTB. The effect of zoledronate and other bisphosphonates on 15 cases of recurrent primary GCTB, four of which had metastasised to the lung, was assessed clinically. Most recurrent tumours did not exhibit progressive enlargement and, in some cases, both primary and metastatic GCTBs showed a degree of radiological improvement following treatment However, tumours did not diminish in size and, in some cases, no apparent treatment effect was noted.

Our findings provide in vitro evidence for the use of bisphosphonates to inhibit the progressive osteolysis associated with GCTB. In vivo, these agents produced a degree of clinical and radiological improvement in some cases. This study reports results from three European centres where bisphosphonates are being used to treat recurrent GCTB and highlights the fact that these centres are all employing different clinical indications and different regimes of bisphosphonate treatment. Bisphosphonates have significant side effects and indications for treatment and standardisation of drug type and dosage regimes (and measurement of agreed outcome measures to determine treatment efficacy) should be established before these agents are included as part of a treatment protocol to control GCTB tumour growth and osteolysis.

Giant cell tumour of bone (GCT) is a primary osteolytic neoplasm, histopathologically characterized by osteoclast-like giant cells and clinically characterized by local bone destruction and high recurrence rates. There is a need to identify risk factors for recurrence. In order to reduce the recurrence rate we initiated an international, multicenter, randomised phase II trial with adjuvantzoledronic acid as compared to standard care for high risk GCT patients.

One hundred and sixteen GCT patients, treated at the LUMC from 1971 to 2006, with a minimal follow-up of a year, were retrospectively analysed for the following risk factors for local recurrence: GCT grade III and tumour involvement into soft tissue caused by ingrowth or fracture. Resection was used as treatment in 21 patients (group A), intralesional surgery with cement or adjuvant in 24 (group B) and intralesional surgery with cementation and adjuvant in 71 patients (group C).

GCT recurred in 5% (1/21) in group A. Risk factors were found in 90% of patients without recurrence (18/20). Group B shows a recurrence of 25% (6/24). Risk factors were found in 83% (5/6) of recurring GCTs, compared with 28% in patients without recurrence. In group C, a recurrence rate of 23% (16/71) was found. Risk factors were present in 94% (15/16) of recurrences, compared to 36% (20/55) in patients without recurrence.

Soft tissue involvement and GCT grade 3 and up are risk factors for recurrence in GCT. Recurrence rates are lowest when resection is used. Risk factors may influence the choice of treatment. High risk patients may benefit from resection or systemic treatment with adjuvant therapy.

Chondrosarcomas are notorious for their resistance to conventional chemo- and radiotherapy, indicating there are no curative treatment possibilities for patients with inoperable or metastatic disease. We therefore explored the existence of molecular targets for systemic treatment of chondrosarcoma using kinome profiling.

Peptide array was performed for 4 chondrosarcoma cell lines and 9 primary chondrosarcoma cultures. Acitivity of kinases was verified using immunoblot and active Src- and PDGFR signaling were further explored using imatinib and dasatinib on chondrosarcoma cell lines and primary cultures.

The AKT1/GSK3B pathway was clearly active in chondrosarcoma. In addition, the PDGFR pathway and the Src kinase family were active. PDGFR and Src kinases can be inhibited by imatinib and dasatinib, respectively. While imatinib did not show any effect on chondrosarcoma cell cultures, dasatinib showed a decrease in cell viability at nanomolar concentrations in 3 out of 5 chondrosarcoma cultures. Whereas inhibition of phosphorylated Src (Y419) was found both in responsive and non-responsive cells, caspase-3 related apoptosis was found only in cell line GIST882, suggesting that the mechanism of decreased cell viability in chondrosarcoma by dasatinib is caspase-3 independent.

In conclusion, using kinome profiling we found the Src pathway to be active in chondrosarcoma. Moreover, in the chondrosarcoma cell lines and primary cultures we showed that the inhibitor of the Src pathway, dasatinib, may provide a potential therapeutic benefit for chondrosarcoma patients which are not eligible for surgery.

High-grade angiosarcomas (HGAS) of bone are rare and represent less than 1% of the primary malignant bone tumours. Because of their rareness little is known. Clinically, it is accepted that they are extremely aggressive. Due to the lack of uniform terminology and accepted histological criteria, terminology and classification of primary malignant vascular tumours of bone has been highly controversial. Today, angiosarcoma is the most accepted term for high-grade primary vascular tumour of bone, recognized by the 2002 WHO Classification. However, distinct histological hallmarks to define a HGAS of bone are not clear.

We collected 64 HGAS of bone diagnosed between 1964 and 2007 from the files of the departments of pathology, Leiden University Medical Center (Leiden), Rizzoli Institute (Bologna) and University Hospitals (Leuven). All clinical, radiological, and pathological data were reviewed and different histological criteria were scored. A tissue micro-array was constructed containing 57 HGAS of bone. To confirm the vascular origin of all lesions and to investigate the diagnostic value of commonly used markers, immunohistochemistry was performed for CD31, CD34, Factor VIII, and keratin AE1/AE3. Staining was evaluated positive or negative.

Among 64 patients with HGAS of bone, there are 41 males and 23 females. There is a wide age distribution, with a nearly equal distribution from the second to the sixth decade. The solitary cases are mostly located in the extremities (66%) followed by trunk (12.8%), axial/central location (10.6%) and pelvis (10.6%). 17 cases (73%) have multifocal bone lesions. HGAS of bone show variable histological patterns. Association with clinical outcome (chi-square test) reveals that there is a significant poor survival when the tumour has tree or more mitoses (p=0.001), a macronucleoli (p=0.011) or there is an absence of an eosinophilic infiltrate (p=0.023). The HGAS of bone are positive for CD31 in 53/55 (96%), CD34 in 33/57 (58%), Factor VIII in 47/55 (86%), and keratin in 40/57 (70%). Only 15 out of 40 (38%) keratin positive angiosarcomas, showed an epithelioid phenotype at classical morphology. All tumours with an epithelioid phenotype are keratin positive.

Although HGAS of bone in general have a poor outcome, histological criteria such as three or more mitoses, the presence of a macronucleolus and the absence of an eosinophilic infiltrate can be useful to predict a more aggressive course, consistent with the clinical behaviour of a high-grade angiosarcoma. CD31 and Factor VIII are the best diagnostic markers for HGAS of bone. It is striking that keratin positivity is seen in the majority of cases, and is independent of epithelioid morphology. Pathologists should be aware of this to avoid misinterpretation as metastatic carcinoma.

Haemangiopericytoma (HPC) was first described by Murray and Stout as a soft tissue neoplasm with distinct morphologic features, presumably composed of pericytes. Over the years, it became clear that many tumours could mimic a HPC-like pattern. These days, it is accepted that in soft tissue most lesions diagnosed as HPC in the past are actually solitary fibrous tumours (SFT), synovial sarcomas (SS) or myofibromatoses. It has been unclear whether the very rare HPC of bone is atrue entity, or that the HPC-like vessels are non-specific and part of other, different entities.

We collected 10 primary HPC of bone from four institutions diagnosed between 1952 and 2002. All data were reviewed. Immunohistochemistry was performed for CD31, CD34, factor VIII, SMA, keratin AE1/AE3 and EMA. Staining was evaluated as focal positive, diffuse positive or negative.

There were five female and five male patients between 21 and 73 years of age (mean 45.3 y). All tumors were located within bone. The primary site of the tumour was the femur in two patients, humerus in one, fibula in one, sacrum in two and vertebra in three. All tumours showed the presence of prominent thin-walled branching vessels surrounded by more undifferentiated spindle or round cells. However these cells showed some variation in their morphologic pattern: five tumours showed a patternless architecture and varying cellularity, consistent with SFT. Three tumours showed more densely packed sheets of poorly differentiated cells, similar to SS, and one case each represented paraganglioma and PEComa, possibly metastatic. Tumours resembling SFT showed usually focal to diffuse staining for CD34. All tumours were negative for SMA. Two tumours more similar to SS showed focal positive staining for keratin AE1/AE3 or EMA (66%). Some tumours showed severe decalcification artefact. None of the 10 tumours show CD31 and factor VIII expression. FISH is performed to study SYT rearrangements.

Our retrospective review of tumours diagnosed as HPC of bone in the past revealed the absence of true pericytic differentiation and the existence of both SFT of bone and SS of bone. Therefore, as in soft tissue tumours, HPC-like features are non specific. Diffuse CD34 staining is helpful to diagnose SFT of bone, whereas keratin/EMA staining is suggestive for SS of bone.

Ewing sarcoma (ES) is an aggressive sarcoma, and is the second most common bone sarcoma in childhood. Disease specific t(11;22)(~85–90%), t(21;22)(~5–10%), or rarer variant translocations with the involvement of chromosome 22 (~5%) are present. At the gene level, the EWSR1 gene fuses with FLI1, ERG or other ETS transcription factor family members. So far, no ES has been identified with a fusion to transcription factors other than ETS.

By using a panel of molecular tools such as multicolor FISH and array-CGH, a ring chromosome containing chromosomes 20 and 22 was identified in four ES cases. Molecular karyotyping showed the translocation and amplification of regions of chromosomes 20q13 and 22q12. Cloning of the breakpoint showed an in-frame fusion between the EWSR1 and NFATc2 genes. The translocation led to the loss of the N-terminal, calcineurin-dependent control region. Consequently, the remaining intact DNA binding domain of NFATc2 is under control of the EWSR1 promoter region permitting oncogenic activation. Intriguingly, in all cases a distinct histological feature was observed.

In conclusion: a new translocation involving EWS and NFATc2 was cloned that is associated with a histological variant of ES. The NFATc2 transcription factor is not a member of the ETS family of transcription factors. NFTAC2 has well characterized functions in T-cell differentiation and immune response. For the first time a direct involvement of NFATc2 in oncogenesis has been shown.

Resection of pulmonary metastases has previously been reported to improve outcome in high grade osteosarcoma (OS) patients with pulmonary metastases. In this study factors influencing survival in OS patients with pulmonary metastases were determined.

One hundred ninety seven patients with OS treated at our institution between 1990 and 2008 under the age of 40 were included. Excluded were patients with insufficient follow-up data (n=12) and irresectable primary tumour (n=11). Of the 174 remaining patients, 26 patients had pulmonary metastases at diagnosis and 62 developed pulmonary metastases during follow-up. Twenty-two of 88 patients (25%) also had extra-pulmonary metastases. Almost all patients with primary non-metastatic OS who experienced a relapse within 310 days (first tertile) died of disease, whereas patients with a relapse free interval of more than 310 days (second and third tertiles) have a significantly better overall survival at about 20% (p=0.02).

In total, 56 (63.6%) of 88 patients with pulmonary metastases were treated by metastasectomy. The main reason not to perform metastasectomy was irresect-ability by number and site. Patients with irresectable pulmonary metastases had higher numbers of pulmonary nodules (mean of six vs. three nodules) and more frequent bilateral involvement than patients eligible for surgery (p-values respectively 0.002 and 0.06). Independent risk factors determining survival after metastasectomy in multivariate analysis were male sex (p=0.05), higher numbers of pulmonary nodules (p=0.03) and necrotic metastases (p=0.04). Patients undergoing repeated metastasectomies had a similar chance of survival as patients who underwent metastasectomy once.

This well-defined cohort of patients with extensive follow-up data enabled us to identify important risk factors determining survival in OS patients with pulmonary metastases. Risk factors determining poor survival after pulmonary metastasectomy were male sex, higher numbers of pulmonary nodules and resection of vital metastases. Furthermore, we demonstrate that even after repeated metastasectomies, curation can be achieved.

Enchondromatosis is a non-hereditary disease, characterised by the presence of multiple enchondromas. While Ollier Disease is typified by multiple enchondromas, in Maffucci Syndrome they are combined with haemangioma.

Due to the rarity of these diseases, systematic studies on clinical behaviour providing information how to treat patients are lacking.

This study intends to answer the following questions: What are predictive factors for developing chondrosarcoma? When is extensive surgery necessary? How often patients die due to dedifferentiation or metastasis?

Twelve institutes in eight countries participated in this descriptive retrospective EMSOS-study. 118 Patients with Ollier Disease and 15 patients with Maffucci Syndrome were included. Unilateral localization of disease was found in 60% of Ollier patients and 40% of patients with Maffucci Syndrome.

One of the predictive factors for developing chondrosarcoma is the location of the enchondromas; the risk increases especially when enchondromas are located in the scapula (33%), humerus (18%), pelvis (26%) or femur (15%). For the phalanges, this risk is 14% in the hand and 16% in the feet. The decision whether or not to perform extensive surgery is difficult, especially in patients who suffer multiple chondrosarcomas.

Malignant transformation was found in fourty-four patients with Ollier Disease (37%) and eight patients with Maffucci Syndrome (53%). Multiple synchronous or metachronous chondrosarcomas were found in 15 patients.

Nine patients died (range 21–54 yrs). Seven of them died disease related due to pulmonary metastasis (2 humerus, 2 pelvis, 3 femur). Two patients died from glioma of the brain.

In conclusion, one important predictive factor for developing chondrosarcoma is the location of the enchondromas; interestingly, only patients with chondrosarcoma outside the small bones died of their disease. In this series, no dedifferentiation of chondrosarcoma was seen. A first design flow-chart how to approach chondrosarcoma in patients with Ollier Disease and Maffucci Syndrome is in preparation.

Ollier disease is a rare skeletal disorder. It is characterized by the occurrence of multiple enchondromas with a marked unilateral predominance mainly affecting medulla of the metaphyses and diaphyses of the short and long tubular bones of the limbs, especially the hands and feet. The risk of malignant transformation is suggested to be up to 35%. We hypothesise that Ollier disease is a mosaic condition as it is polyostotic and because of its unilateral predominance. Here we aimed to identify molecular defects in Ollier disease related enchondromas and chondrosarcomas using high resolution single nucleotide polymorphism (SNP) array approach. Affymetrix SNP 6.0 was performed on 67 samples which include 10 blood samples and 3 matched blood-saliva samples as a control; 13 enchondromas and 26 chondrosarcomas of different grades from 30 Ollier patients and normal DNA from 12 Ollier patients for paired comparison.

All samples were divided into three groups: normals, enchondromas and chondrosarcomas. The number of numerical genomic changes in the chromosomes were not different for the enchondromas (p=0.36) while large genomic aberrations were seen in chondrosarcomas as compared to normals (p=0.01). Copy number variation (CNV) analysis showed 95K amplification at 4q13 in 5 out of 13 enchondromas and a 2K deletion at 14q11 in 6 out of 13 enchondromas. Paired loss of heterozygosity (LOH) analysis failed to show LOH in 5 enchondromas at higher resolution. Paired LOH was observed at 3q, 5p, 6p, 6q, 7q, 9p, 12p, 13p and 13q in 7 high grade chondrosarcomas associated with loss of chromosomes.

The results of this study indicate involvement of chromosomes 4 and 14 for the development of enchondromas. We were unable to detect LOH in enchondromas at 1Mb resolution containing approximately 500 SNP probes. High grade chondrosarcomas showed LOH at different chromosomes. In future, we will study LOH and CNV changes at gene level and select candidate genes.

While classically bone tumors were classified according to the differentiation and cellular morphology at the light microscopical level, it has become clear that over the past decade the array of knowledge which became available on the cytogenetic and molecular genetic level should influence tumor classification. This lead to an integrated approach in drafting the 2002 WHO nomenclature for bone tumors in which morphology was combined with the evolving genetic information. With regard to bone tumorigenesis distinct patterns can be recognized with regard to underlying genetics:

balanced translocations such as in Ewing sarcoma, or aneurysmal bone cysts

These different pathways in oncogenesis open an array of possibilities for studying the drivers in oncogenesis. Especially those pathways essential in keeping the proliferative state as opposed to the ones governing differentiation might proof to be potential targets for tailored drug treatment. Here high throughput screens focusing on kinase activity appear especially of interest. Within the EuroBoNeT consortium (www.eurobonet.eu) several working groups act transnationally together in unraveling these events. Important key elements of study are the molecular-genetic networks involved in skeletogenesis as well, which amongst others are studied within the consortium using in vitro systems as well as in vivo models using xenografted mouse models, mesenchymal stem cell models and models exploring zebrafish development.