Courtesy: Dr James Wittig,
Orthopaedic Oncologist

Chondrosarcoma: Structured Clinical Summary

Overview and Classification

Chondrosarcoma is a malignant cartilage forming tumor with multiple histologic subtypes.
It may arise primarily within normal bone or secondarily from preexisting lesions such as enchondroma or osteochondroma.
Primary tumors constitute most cases, while secondary tumors are less common.
Major subtypes include conventional intramedullary, clear cell, mesenchymal, dedifferentiated, and periosteal chondrosarcoma.

Most common subtype, usually affecting adults older than forty years.
Common locations include pelvis, proximal femur, distal femur, proximal humerus, ribs, and scapula.
Patients typically present with pain, sometimes associated with swelling; pathological fracture is uncommon.
Radiographs show metaphyseal or diaphyseal lesions with ring and arc calcifications and endosteal scalloping.
Malignant features include cortical thickening, deep endosteal scalloping, cortical destruction, bone expansion, and soft tissue extension.

Low grade chondrosarcoma typically occurs in older patients and presents with pain related to the lesion.
Lesions are usually larger than five centimeters with deeper endosteal scalloping.
Bone scan uptake is usually greater than the anterior superior iliac spine.
Soft tissue extension, cortical thickening, and periosteal reaction favor malignancy.

Grade one tumors resemble benign cartilage with low cellularity and minimal atypia but demonstrate entrapment of host trabeculae.
Grade two tumors show increased cellularity, nuclear enlargement, binucleation, and occasional mitoses.
Grade three tumors demonstrate marked pleomorphism, high cellularity, spindle morphology, and frequent mitoses.
Higher grade correlates with increased risk of metastasis and aggressive behavior.

Characterized by abrupt transition between low grade cartilage tumor and high grade noncartilaginous sarcoma.
Common high grade components include osteosarcoma, fibrosarcoma, and undifferentiated pleomorphic sarcoma.
Highly aggressive tumor with poor prognosis and high metastatic rate.
Radiographs show biphasic pattern with calcified cartilage component and adjacent destructive lytic area with soft tissue mass.

Arises from osteochondroma or enchondroma, often in pelvis, scapula, ribs, or proximal femur.
Malignant transformation suspected with cartilage cap thickness greater than two centimeters on imaging.
Other concerning features include growth after skeletal maturity, cortical destruction, and increasing pain.

Rare low to intermediate grade tumor usually arising in the epiphysis of long bones.
Most common sites include proximal femur and proximal humerus.
Radiographs show lytic epiphyseal lesion with mild sclerosis and minimal calcification.
Histology shows clear cytoplasm rich in glycogen and S100 positivity.

High grade tumor composed of small round cells with islands of malignant cartilage.
Occurs in young adults and may arise in bone or soft tissue.
Common sites include femur, ribs, pelvis, jaw, and spine.
Characterized by aggressive behavior with high metastatic potential.

Surface tumor arising from periosteum and eroding cortex without medullary involvement.
Common in femur and humerus and usually presents as painless swelling.
Radiographs show saucerization of cortex with soft tissue mass and chondroid calcification.

Surgical resection is the primary treatment for all chondrosarcoma subtypes.
Limb sparing surgery is preferred when feasible, though amputation may be required in advanced cases.
Chemotherapy and radiotherapy are generally ineffective except in selected high grade or unresectable tumors.
Prognosis depends mainly on histologic grade, with higher grade tumors showing worse outcomes.