Chondrosarcoma

Introduction
Malignant chondrogenic lesions can occur in two forms primary chondrosarcoma which includes low-grade, high-grade, de-differenitated chondrosarcoma clear cell chondrosarcoma  mesenchymal chondrosarcoma  secondary chondrosarcoma arises from benign cartilage lesions including  osteochondroma (<1% risk of malignant transfomation) multiple hereditary exostosis (1-10% risk of malignant transfomation) enchondromas (1% risk of malignant transfomation) Ollier's disease (25-40% risk of malignant transfomation) Marfucci's (100% risk of malignant transfomation) Age & location typically, chondrosarcomas are found in older patients (40-75 yrs) there is a slight male predominance most common locations include the pelvis, proximal 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 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 and require more aggressive treatment including adjuvant chemotherapy Prognosis axial and proximal extemity lesions have a more aggressive course histologic grade correlates with survival Grade I: 90% survival Grade II: 60-70% survival Grade III: 30-50% survival De-differentiated chondrosarcoma: 10% survival increased telomerase activity in chondrosarcoma, as determined byreverse transcriptase-polymerase chain reaction (RT-PCR), has been shown to directly correlate with the rate of reccurence  Primary 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

Symptoms

Presentation pain is the most common symptom 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 lytic or blastic lesion with reactive thickening of the cortex  low-grade chondrosarcomas have a similiar appearance to enchondromas with additional cortical thickening/expansion and endosteal erosion   high-grade chondrosarcomas are less well defined on plain radiographs and frequently present with cortical destruction and a soft tissue mass intra-lesional "popcorn" mineralization  may be seen described as rings, arcs, and stipples of mineralization de-differentiated chondrosarcomas radiographically show a lower grade chondroid lesion with superimposed highly destructive area consistentwith the high grade transformed dedifferentiated chondrosarcoma  MRI or CT helpful to determine cortical destruction, marrow involvement, and the soft tissue involvement  Bone scan is usually very hot in all grades of chondrosarcoma

Histology

Chondrosarcoma needle biopsy is not indicated for cartilage tumors due to difficulties with diagnosis it is often difficult to determine malignancy based on histology alone chararcteristic histology low-grade chondrosarcomas show few mitotic figures with a bland histologic appearance and associated enlarged chondrocytes with plump multinucleated lacunae  high-grade chondrosarcomas have a hypercellular stroma consisting of characteristic "blue-balls" of a cartilage lesion which permeate the bone trabeculae  enchondromas of hand, Ollier's disease, Maffucci's disease, periosteal chondromas, and chondrosarcoma may all have similar histology De-differentiated chondrosarcomas characterized by a bimorphic histology low grade chondroid component high grade spindle cell component (similiar histology to osteosarcoma, fibrosarcoma, MFH)

Treatment

Operative intra-lesional curettage  indications Grade 1 lesions  treatment of grade 1 lesions located in the pelvis or axial skeleton is controversial many authors recommend wide excision of all chondrosarcomas (even grade 1) if located in the pelvis wide surgical excision  indications grade 2 or 3 lesions some say grade 1 lesions in pelvis historically, there is no significant role for radiation or chemotherapy in typical intramedullary chondrosarcoma  wide surgical excision combined with multi-agent chemotherapy  indications high-grade de-differentiated chondrosarcoma mesencymal chondrosarcoma