summary Chondrosarcomas are malignant primary bone tumors composed of chondrocytes with variable degrees of malignancy that are most commonly found in the pelvis and proximal femur. Patients typically present after the age of 40, with a progressively painful mass. Diagnosis is made with biopsy showing hypercellular stroma consisting of characteristic "blue-balls" of a cartilage lesion which permeate the bone trabeculae. Treatment is usually wide surgical resection. Epidemiology Demographics typically, chondrosarcomas are found in older patients (40-75 yrs) there is a slight male predominance Anatomic location most common locations include the pelvis, proximal femur, distal femur, scapula tumor location is important for diagnosis as the same histology may be diagnosed as benign in the hand but malignant if located in the long bones Etiology Forms primary chondrosarcoma which includes low-grade, high-grade, dedifferentiated chondrosarcoma clear cell chondrosarcoma (see below) mesenchymal chondrosarcoma (see below) secondary chondrosarcoma arises from benign cartilage lesions osteochondroma (<1% risk of malignant transfomation) multiple hereditary exostosis (1-10% risk of malignant transformation) enchondromas (1% risk of malignant transformation) Ollier's disease (25-30% risk of malignant transformation) Maffucci's (25-30% risk of malignant transformation) Classification Grade 85% of chondrosarcomas are grade 1 or 2 15% of chondrosarcomas are grade 3 or dedifferentiated chondrosarcoma de-differentiated chondrosarcomas are high grade lesions which develop from low grade chondroid lesions Chondrosarcoma sub-types Clear cell chondrosarcoma malignant immature cartilaginous tumor accounting for <2% of all chondrosarcomas most common in 3rd and 4th decades of life commonly presents with insidious onset of pain presents as an epiphyseal lesion and can be mistaken for low-grade chondroblastoma locally destructive with potential to metastasize Mesenchymal chondrosarcoma chondrosarcoma variant which presents with a biphasic pattern of neoplastic cartilage with associated neoplastic small round blue cell component occurs in younger patients than typical chondrosarcomas may occur at several discontinuous sites at presentation and can occur in the soft tissues treatment includes neo-adjuvant chemotherapy followed by wide surgical resection Presentation Symptoms pain is the most common symptom variable rapidity of presentation dependent on tumor grade and location may present with slowly growing mass or symptoms of bowel/bladder obstruction due to mass effect in the pelvis 50% of de-differentiated chondrosarcomas present with a pathologic fracture Imaging Radiographs views AP and lateral views findings lytic or blastic lesion with reactive thickening of the cortex 85% of patients have significant cortical changes low-grade chondrosarcomas show similar appearance to enchondromas with additional cortical thickening/expansion and endosteal erosion high-grade chondrosarcomas show cortical destruction and a soft tissue mass intra-lesional "popcorn" mineralization may be seen described as rings, arcs, and stipples of mineralization, more prevalent as lesions age de-differentiated chondrosarcomas radiographically show a lower grade chondroid lesion with superimposed highly destructive area consistent with the high grade transformed dedifferentiated chondrosarcoma mesenchymal chondrosarcomas appear similar to Ewing sarcoma with permeative bone destruction and periosteal reaction MRI indications MRI helpful to determine marrow and soft-tissue involvement findings typically dark on T1 and bright on T2 in non-mineralized portions due to high water content heterogeneous and moderate contrast uptake, can be most in fibrovascular connective tissue separating cartilage lobules CT indications CT most useful study for low grade cartilage neoplasms to determine cortical involvement findings matrix calcifications more easily identified on CT compared to radiographs deep endosteal scalloping suggests chondrosarcoma instead of enchondroma 90% have cortical breach Bone scan indications can help distinguish (not definitively) chondrosarcoma and enchondroma can determine location of metastastic disease findings usually very hot in all grades of chondrosarcoma Histology Chondrosarcoma needle biopsy is not indicated for cartilage tumors due to difficulties with diagnosis lesions are often heterogenous and difficult to diagnose on histology alone diagnosis requires clinical, pathologic, and radiographic correlation characteristic histology low-grade chondrosarcomas show features similar to enchondroma few mitotic figures with a bland hyaline cartilage appearance hypercellularity and disorganization enlarged chondrocytes with plump multinucleated lacunae high-grade chondrosarcomas show hypercellular stroma consisting of characteristic "blue-balls" of a cartilage lesion which permeate the bone trabeculae benign cartilage appearance and lacunar structure is absent more disorganization, more pleomorphism, and more mitotic figures enchondromas of hand, Ollier's disease, Maffucci's disease, periosteal chondromas, and chondrosarcoma may all have similar histology De-differentiated chondrosarcomas most malignant of cartilage tumors, < 10% long-term survival characterized by a bimorphic histology low grade chondroid component high grade spindle cell component (similar histology to osteosarcoma, fibrosarcoma, MFH) 80% are chondrosarcomas with an extra destructive area Mesenchymal chondrosarcoma biphasic appearance with low grade chondrosarcoma adjacent to small, round blue cells Clear cell chondrosarcoma lobular architecture similar to other cartilage neoplasms, but cells are large and vacuolated typically low to intermediate grade Differential Differential of Chondrosarcoma Malignant lesion in older patient May have similar chondrogenic histology Sacral lesions in older patients Treated with wide resection alone Chondrosarcoma o o o o Metastatic disease o o Lymphoma o o Myeloma o o MFH o o Secondary sarcoma o Enchondroma / Olliers / Maffuccis o Periosteal chondroma o Osteochondroma (MHE) o Parosteal osteosarcoma o Adamantinoma o Chordoma o o Squamous cell o o Treatment Nonoperative chemotherapy & radiation indications chondrosarcomas are generally resistant to chemotherapy and radiation Operative intra-lesional curettage indications Grade 1 lesions in the extremities (minimal rate of metastasis) treatment of grade 1 lesions located in the pelvis or axial skeleton is controversial (higher rate of local recurrence and metastasis) most authors recommend wide excision of all chondrosarcomas (even grade 1) if located in the pelvis wide surgical excision indications grade 2 or 3 lesions grade 1 lesions in pelvis wide surgical excision combined with multi-agent chemotherapy indications mesenchymal chondrosarcoma the role of chemotherapy in de-differentiated chondrosarcoma is very controversial Complications Local recurrence for high-grade lesions, local recurrence associated with distant metastasis and decreased survival grade 1 chondrosarcoma: rare after wide resection with negative margins 5-15% after curettage with adjuvant treatment grade 2 chondrosarcoma: varies depending on resection margins grade 3 chondrosarcoma: 25% local recurrence rate and >30% rate of metastasis Prognosis Histologic grade correlates with survival Grade I 90% 5-year survival grade 1 chondrosarcomas are generally slow growing Grade II 60-70% 5-year survival Grade III 30-50% 5-year survival De-differentiated chondrosarcoma <10% 5-year survival Poor prognostic variables axial and proximal extremity lesions have a more aggressive course pelvic location advanced patient age inadequate surgical margins Increased telomerase activity as determined by reverse transcriptase-polymerase chain reaction (RT-PCR), increased telomerase activity has been shown to directly correlate with the rate of recurrence referral to orthopedic oncologist is necessary for best prognosis