Chondrosarcoma - Foot and Ankle

Summary
Description

Chondrosarcoma is the most common malignant bone tumor in the foot in some reported series. Most chondrosarcomas are low grade, but dedifferentiated chondrosarcoma can occur in the setting of a longstanding benign cartilage lesion such as enchondroma.

People and Age
The peak age of presentation is in the 50's and 60's, and the to female ratio of 1.5 to 1. It is most common in the femur, humerus, ribs and on the surface of the pelvis. Patients with Ollier's disease (multiple enchondromatosis) or Maffucci's syndrome (multiple enchondromas and hemangiomas) are at much higher risk of chondrosarcoma than the normal population and often present in the third and fourth decade.
Symptoms and Presentation:
Symptoms and Presentation
The lesion presents as a slow growing mass with mild pain.
Brief description of the xray
The radiographs will show a lytic lesion which may demonstrate ring and arc formations.
Brief desc of tx
Treatment for low grade chondrosarcoma may include curettage or marginal excision.
Benign or Malignant
Body region
Most Common Bones
Tumor density
Complete Information on this Tumor
Introduction and Definition

Chondrosarcoma is the most common malignant bone tumor in the foot in some reported series. Patients with multiple cartilage lesions, such as Ollier's disease, or multiple enchondromas are at increased risk. This tumor has several subtypes, including clear cell chondrosarcoma, and mesenchymal chondrosarcoma, which can occur in bone and in the soft tissues, where it presents as as an innocent bump. Most chondrosarcomas are low grade, but dedifferentiated chondrosarcoma can occur in the setting of a longstanding benign cartilage lesion such as enchondroma.

Incidence and Demographics
The peak age of presentation is in the 50's and 60's.
Symptoms and Presentation

The lesion presents as a slow growing mass with mild pain.

X-Ray Appearance and Advanced Imaging Findings
The radiographs will show a lytic lesion which may demonstrate ring and arc formations. Cortical expansion, breakthrough, and a soft tissue mass are signs of malignant behavior.

On plain radiographs, chondrosarcoma of the long bones is a fusiform, lucent defect with scalloping of the inner cortex and periosteal reaction. Extension into the soft tissue may be present as well as punctate or stippled calcification of the cartilage matrix.

MRi shows high signal intensity on T2 sequences, and low intensity signal on T1 sequences. Calcification within the mass, if it occurs, will appear as very low signal areas.
MRI Findings
MRi shows high signal intensity on T2 sequences, and low intensity signal on T1 sequences. Calcification within the mass, if it occurs, will appear as very low signal areas.
CT Findings
CT is helpful in defining the integrity of the cortex and distribution of calcification.
Laboratory Findings
no labs are helpful in the diagnosis
Differential Diagnosis
Osteosarcoma, benign cartilage lesions such as CMF, chondroblastoma
Preferred Biopsy Technique for this Tumor
open - incisional
Histopathology findings
On gross examination, chondrosarcoma is a grayish-white, lobulated mass. It may have focal calcification, mucoid I degeneration, or necrosis.Histologically, chondrosarcoma is differentiated from benign cartilage growths by enlarged plump nuclei, multiple cells per lacunae, binucleated cells, and hyperchromic nuclear pleomorphism. Chondrosarcoma is graded from 1 (low) to 3 (high). Low grade chondrosarcoma is very close in appearance to enchondromas and osteochondromas and has occasional binucleated cells. High grade chondrosarcomas have increased cellularity, atypia and mitoses. There is an inverse relationship between histologic grade and prognosis with higher grades having a worse prognosis and early metastases.
Treatment Options for this Tumor
Treatment for low grade chondrosarcoma may include curettage or marginal excision. Intermediate and high grade lesions should be excised with a wide margin. Clear margins are essential, because no truly effective adjuvant therapy exists.

Chemotherapy and radiotherapy are not effective and are normally not used for lesions in the foot. Rather, complete removal with a wide margin is the correct treatment. Amputation of the affected part is employed if necessary to achieve a wide margin. Incompletely excised lesions should be referred to a musculoskeletal oncologist for re-resection.
Outcomes of Treatment and Prognosis
Patients with adequately resected low grade chondrosarcomas have an excellent survival rate. The survival of patients with high grade tumors depends on the location, size and stage of the tumor.
Special and Unusual Features
There are three additional types of chondrosarcoma. Mesenchymal chondrosarcoma is a rare variant with a bimorphic histologic picture of low grade cartilaginous cells and hypercellular small, uniform, and undifferentiated cells that resemble Ewing's sarcoma. Mesenchymal chondrosarcoma has a predilection for the spine, ribs and jaw and it presents in the third decade. It is more common in females and can grow exceptionally large. It is very likely to metastasize to lungs, Iymph nodes and other bones. Clear cell chondrosarcoma is a malignant cartilage tumor that may be the adult variant of chondroblastoma. It is a rare, low-grade tumor with an improved prognosis over other chondrosarcomas. Likechondroblastoma, it is found in the epiphysis of the femur and humerus. Histologically, soft tissue invasion is rare. Clear cell chondrosarcoma has clear cells with vacuolated cytoplasm. The cartilage matrix has significantly calcified trabeculae and giant cells. Dedifferentiated chondrosarcoma is the most malignant form of chondrosarcoma. This tumor is a mix of low grade chondrosarcoma and high grade spindle cell sarcoma where the spindle cells are no longer identifiable as having a cartilage origin. The dedifferentiated portion of the lesion may have histological features of malignant fibrous histiocytoma, osteosarcoma, or undifferentiated sarcoma. This biphasic quality is evident on x-ray with areas of endosteal scalloping and cortical thickening are contrasted with areas of cortical destruction and soft tissue invasion. Dedifferentiated chondrosarcoma has a 5 year survival of 10%.