chondrosarcomas

Chondrosarcoma is a malignant neoplasm characterized by the production of cartilage by tumor cells. It is the second most common primary malignant bone tumor in adults and typically affects the axial skeleton and proximal long bones. Peak incidence is middle to older age, with a slight male predominance. Conventional chondrosarcoma accounts for the majority of cases and is graded histologically from 1 to 3, with higher grades associated with increased cellularity, mitotic activity, and less cartilaginous matrix.

Other variants include dedifferentiated chondrosarcoma, which contains a high-grade noncartilaginous sarcoma component and has a poorer prognosis; mesenchymal chondrosarcoma, a rare aggressive form often presenting with rapid growth; clear cell chondrosarcoma, typically a low-grade tumor arising in the epiphysis and associated with a relatively favorable prognosis; and periosteal or juxtacortical chondrosarcoma, which arises on the bone surface. There are also rare subtypes and variants.

Clinical presentation is usually progressive deep bone pain, sometimes with swelling or a palpable mass. Imaging typically shows a cartilaginous matrix with calcifications on radiographs, cortical thinning or endosteal scalloping, and extent defined by MRI and CT. Metastasis most commonly involves the lungs.

Diagnosis relies on histopathology from a biopsy, demonstrating cartilaginous differentiation with grade-dependent features. Staging includes assessment for metastatic disease.

Treatment is primarily surgical, with wide resection and negative margins being the standard of care. Conventional chondrosarcomas are relatively resistant to chemotherapy and radiotherapy; radiotherapy or newer modalities may be considered for unresectable tumors or palliation, or in select subtypes such as mesenchymal chondrosarcoma. Prognosis depends on histologic grade and extent of disease; higher-grade and dedifferentiated tumors have higher risk of recurrence and metastasis.