General Information
- Benign neoplasm
- Composed of mature hyaline cartilage
- Arises from surface of bone from inner layer of periosteum
- Erodes the outer table of the cortex
- Does not grossly extend into medullary cavity
- Also known as juxtacortical chondroma
- More cellular than an enchondroma
Clinical Presentation
Signs/Symptoms:
- Incidental radiographic findings
- Possible symptomatic mass
- Mildly painful
- Long duration of symptoms
- Mechanical symptoms
Prevalence:
- Very uncommon
- Accounts for ~0.66% of bone tumors
- 3 times as common as juxtacortical chondrosarcoma
- 2 to 1 male predilection
Age:
- All ages; usually <30 years
- Most commonly in second or third decades of life
Sites:
- Almost all in appendicular skeleton
- Proximal humerus-Most common
- Femur, tibia, phalanges are common sites
- Pelvis, ribs, vertebrae less common
- Occasionally multiple lesions occur
- Difficult to differentiate from periosteal chondrosarcoma (periosteal chondrosarcomas are usually
- greater than 6cm and periosteal chondromas are usually less than 6 cm)
Radiographic Presentation




Gross Pathology
- Well circumscribed
- Appears to be embedded in underlying cortical bone
- Typically covered by a thin shell of reactive, often ossified periosteum
- Medullary cavity not grossly invaded
- Cross-section
- Blue-gray to white
- Translucent hyaline cartilage
- Often formed as lobules
- Calcification occasionally noticeable
- Yellow-white, gritty foci
Microscopic Pathology
- Lobulated, obviously hyaline cartilage tumor
- Cartilaginous lobules separated by fibrous connective tissue or well-formed lamellar bone
- Calcium deposition occasionally present
- Necrosis absent
- Cartilaginous lobules separated by fibrous connective tissue or well-formed lamellar bone
- Innermost margin of lesion usually demarcated by rim of lamellar bone
- Considerable interlesional variation in cellularity and pleomorphism
- Many consist of normocellular benign hyaline cartilage
- Binucleated chondrocytes are invariably present
- May be more cellular than an enchondroma with myxoid change of matrix
- About 2/3 of tumors display
- Nuclear enlargement
- Hypercellularity with hyperchromasia
- Or myxoid change of the matrix

Microscopic Pathology: Periosteal Chondroma
Biological Behavior
- No metastasis
- No malignant change
- Exceedingly rare recurrence
- Non aggressive
Treatment & Prognosis
- Marginal excision without removal of surrounding tissue
- Occasional rare recurrence
- En bloc excision
- Invariable curative