Bone Tumors
Mesenchymal Chondrosarcoma
James C. Wittig, MD
Sarcoma Surgeon
Orthopedic Oncologist
GENERAL INFORMATION
High grade malignant, cartilage-forming tumor
Comprised primarily of noncartilaginous small, round, oval, or spindle shaped cells with islands of malignant cartilage dispersed throughout noncartilaginous component of tumor
Osteoid may be present as well
Tumor frequently has a hemangiopericytoma-like appearance
Metastasizes to the lungs and lymph nodes
May have chondroid matrix calcification
CLINICAL PRESENTATION
Signs/Symptoms:
Pain and occasionally swelling
~ 1/3 of patients are symptomatic for more than 1 year
Prevalence:
~2% of all chondrosarcomas
No sexual or racial predilection
Age:
All ages
Predominantly affects those between the ages of 10 and 40
Sites:
Arises in bone and soft tissue (1/3 of cases arise from soft tissue)
Favors the femur, ribs, spine, maxilla, mandible, and pelvis
Other long tubular bones and phalanges may also be affected
RADIOGRAPHIC PRESENTATION
Aggressive motheaten to permeative lesion
Indistinct border in most cases
Osseous destruction with a soft tissue component
Chondroid matrix calcification may be present (60-70% of cases)
Soft tissue mass
Plain X-ray: Mesenchymal Chondrosarcoma from Proximal Humerus
Plain Radiograph of an Extraskeletal Mesenchymal Chondrosarcoma
Plain X-ray: Extraskeletal Mesenchymal Chondrosarcoma of Popliteal Fossa
MRI: Extraskeletal Mesenchymal Chondrosarcoma of Popliteal Fossa
MRI with Gadolinium: Extraskeletal Mesenchymal Chondrosarcoma
Extensive Necrosis Demonstrated indicative of High Grade Tumor
MRI: Extraskeletal Mesenchymal Chondrosarcoma
CT Scan: Extraskeletal Mesenchymal Chondrosarcoma of Popliteal Fossa
No Mineralization Detected
GROSS PATHOLOGY
Gross appearance is variable
Ranging from soft to firm
Gray to pink
Occasionally have a faintly lobulated pattern
Grossly obvious cartilage is rarely visualized
MICROSCOPIC PATHOLOGY
Neoplastic cells may be small, round, oval, or spindle shaped
Undifferentiated mesenchymal cells similar to Ewing sarcoma
Low grade islands of cartilage scattered throughout the mesenchymal cells
Usually only a small part of lesion
Cytologically low grade
Usually sharply demarcated from surrounding stroma
Stain S-100 positive
Cells within cartilage
Tend to have round or ovoid nuclei
Lacunae are poorly formed
May contain islands of collagen resembling osteoid
Lesions are vascular and often have large, anastomosing vessels that impart hemangiopericytoma-like pattern
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Mesenchymal Small Round
Blue Cell Component |
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Cartilaginous
Component |
| Cartilage Component |
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(arrows)
Mesenchymal Component |
Mesenchymal (Small Round Blue Cell) Component
Large Nuclei; No Cytoplasm; No Matrix
Mesenchymal (Small Round Blue Cell) Component
Hemagiopericytoma-like Pattern of Blood Vessels
Large Staghorn Blood Vessels
DIFFERENTIAL DIAGNOSIS
Ewing Sarcoma
Small Cell Osteosarcoma
Dedifferentiated Chondrosarcoma
BIOLOGICAL BEHAVIOR
Locally aggressive
Cortical destruction in approximately half of cases
Extension of tumor into adjacent soft tissues
High metastatic and local recurrence rates
Metastasizes primarily to lungs, other bones, lymph nodes and viscera
Metastases may not appear for over 5 years after treatment
Over 70% mortality
TREATMENT & PROGNOSIS
Most patients are treated with a combination of surgery and chemotherapy. Radiation is used in selected cases, particularly extraskeletal mesenchymal chondrosarcomas
Wide/Radical limb sparing surgery whenever feasible (most cases)
Amputation for very large or unresectable tumors
Limb Sparing Surgery for Extraskeletal Mesenchymal Chondrosarcoma of Popliteal Fossa
Tumor
(left arrow) Portion of Popliteal Artery Removed with Tumor
(right arrow) Sciatic Nerve
Popliteal Artery Re-anastomosed
Specimen
Limb Sparing Surgery for Extraskeletal Mesenchymal Chondrosarcoma of Popliteal Fossa
Intraoperative Arteriogram demonstrating Patency of Popliteal Artery at Conclusion of Surgery
Limb Sparing Surgery for Extraskeletal Mesenchymal Chondrosarcoma of Popliteal Fossa
Rotational Sartorius Muscle Flap for Closure
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