Tumor biology and incidence
- Rare benign, aggressive cartilage tumor characterized by lobulated areas of spindle shaped and myxoid (stellate) cells, with abundant chondroid or myxoid matrix and interspersed giant cells
- Not known to metastasize.
- Least common cartilage tumor, 1% of all primary bone tumors
- Accounts for 2% of benign bone tumors
Age
Most common from 10-30 years of age; mainly adolescents and young adults
Gender
Male:Female = 2:1
Presentation
- Pain near a joint without a history of trauma
- Occasionally tender wwelling
- Pathologic fracture (rare)
- May present with a soft tissue mass and restriction of motion
- Constitutional symptoms usually absent
Physical findings
- Swelling
- Tenderness to palpation of the affected area
- Decreased range of motion
Plain films
- Eccentric, radiolucent lesions with well-defined margins
- Sclerotic border and "soap bubble" appearance common
- Usually a purely lytic lesion, but can have mineralization and calcification
- No periosteal reaction
Site
- Metaphysis of long, tubular bones
- More often found in the lower extremity: proximal tibia, distal femur
- Usually central in location if in the small bones of the hand
Size
Between 1 and 10 cm, with 3-4 cm the average
Tumor effect on bone
- Radioluscent
- Can cause fusiform expansion in small bones
Bone response to tumor
- Sharply circumscribed, geographic, with a sclerotic, scalloped margin
- Metaphyseal reactive sclerosis frequently observed, producing the geographic margin
- Eccentric lobulated bony expansion/periosteal neo-corticalization may occur
- Pseudocapsule appearance
Matrix
Calcifications not often seen on plain radiographs
Cortex
Often eroded or ballooned out
Soft tissue mass
None
Bone scan
- Increased uptake of chondromyxoid fibromas seen on bone scan, but contributes little to diagnosis
- Multiple lesions highly uncharacteristic of chondromyxoid fibroma
CT scan
- Helps define architecture and cortical integrity
- Can show mineralization of tumor
MRI
Typical cartilaginous lesions: Demonstrate low signal intensity on T1-weighted images and high signal intensity on T2-weighted images
Differential diagnosis
- Giant cell tumor (generally older patients, do not have calcifications; borders generally less well defined)
- Chondrosarcoma
- Fibrous dysplasia and non-ossifying fibroma
- Chondroblastoma (epiphyseal; rarely metaphyseal)
- Unicameral bone cyst (rare after teens; lesion is central)
- Aneurysmal bone cyst (also eccentric, but has greater cortical expansion)
- Infection
- Osteoblastoma
- Osteosarcoma (either telangiectatic or chondroblastic)
- Brown tumor
Natural history
- No metastatic cases reported
- Can be locally aggressive
- Can cause bone destruction
- Propensity to recur once treated
- If untreated, tends to grow and infiltrate surrounding tissues
Pathology
- Gross: firm tan tissue
- Microscopic: Lobular pattern
- Lobule is less cellular centrally
- Composed of stellate cells in a myxoid or chondroid type matrix
- At periphery, more cellular, with spindle shaped cells
- Multinucleated cells also present
Diagnosis and treatment
- Open biopsy usually necessary for this rare tumor
- Curettage and bone grafting or marginal excision
- Consider en bloc resection with a marginal margin if location permits removal without significant associated morbidity
- Recurrence rates lower than 20%
Complications
- Local recurrence rates reported between 15-25%, depending on age of the patient and type of resection (higher with intralesional excision)
- Pathologic fracture through the lesion occurs 5% of the time
- Complications related to surgical treatment
- Infection
- Failure of allograft
- Fracture
- Malignant transformation rare; reported in association with radiation treatment
Recommended reading
Nielsen GP, Keel SB, Dickersin GR, Selig MK, Bhan AK, Rosenberg AE.Chondromyxoid fibroma: a tumor showing myofibroblastic, myochondroblastic, and chondrocytic differentiation. Mod Pathol. 1999 May;12(5):514-7.
Wu CT, Inwards CY, O'Laughlin S, Rock MG, Beabout JW, Unni KK. Chondromyxoid fibroma of bone: a clinicopathologic review of 278 cases. Hum Pathol. 1998 May;29(5):438-46.
Yamaguchi T, Dorfman HD.Radiographic and histologic patterns of calcification in chondromyxoid fibroma. Skeletal Radiol. 1998 Oct;27(10):559-64.