Fact-sheet: Enchondroma
Updated on 06/15/2020 at 11:29 AM
View all RADEOS cases associated with this fact-sheet
Definition
Benign bone tumor characterized by proliferation of mature hyaline cartilaginous tissue
Tumor of young subjects, very common, generally discovered incidentally around 30-40 years of age
Location of solitary Enchondroma:
- finger (most common finger tumor), P1 (50%), metacarpal (30%), and P2 (20%)
- long bones:
- proximal humeral metaphysis (13%)
- distal femur (7%)
- proximal tibia (7%)
- rarer in the fibula and radius
- ribs (common)
- rare in the flat bones of the axial skeleton
- exceptional in the skull, face, and patella.
Features raising suspicion of a sarcomatous component:
- girdle location (pelvis and scapulas)
- epiphyseal location
- swelling or pain in the absence of fracture
Look for cutaneous angioma: Maffucci syndrome
Clinical features
- In the majority of cases, they are asymptomatic and discovered incidentally during a radiographic examination or bone scintigraphy.
- A fracture is the presenting finding in 1 out of 3 cases of Enchondroma of the hand and 1 out of 10 cases in long bones
- Enchondromas in epiphyseal location are reportedly associated with pain in 70% of cases.
Radiography
Enchondroma:
- lucency most often central but often eccentric in small bones (phalanges)
- metaphyseal location (80%), metaphyso-diaphyseal, diaphyseal, epiphyseal (6%)
- size
- well defined, without peripheral sclerosis (type 1b), with rounded or scalloped margins due to the lobulated architecture of chondromas
- normal cortices, site of endosteal scalloping, expanded or thickened by compact periosteal reaction
- with cartilaginous matrix and "arcs and rings" calcifications, punctate or "popcorn"-like, of variable abundance
- no periosteal apposition
Juxtacortical chondroma:
- Cortical scalloping at its base of implantation
- Cortical discontinuity
CT
See radiograph
MRI
The tumor is composed of cartilaginous lobules showing:
- T1 hyposignal
- marked, pseudo-fluid T2 hypersignal (except in calcified areas), rimmed by septa in hyposignal
- no perilesional edema (unless there is an associated fracture)
- Calcifications show T1 and T2 hyposignal
- No soft-tissue extension
- Peripheral enhancement and "arcs and rings" septal enhancement after IV gadolinium administration
The presence of fatty marrow persisting between the cartilage lobules has been considered a feature favoring chondroma or grade 1 Chondrosarcoma and arguing against grade 2 or 3 Chondrosarcoma.
Nuclear medicine
Moderate uptake on bone scintigraphy and Nuclear Medicine imaging
The intensity of uptake is one of the criteria used to differentiate enchondroma from chondrosarcoma
Differential diagnosis
Low-grade chondrosarcoma:
- presence of pain
- large size (>5-8 cm)
- diaphyseal endosteal scalloping >2/3 of the cortical thickness or extending over >2/3 of the image height, or resulting in widening of the medullary cavity diameter of a long bone
- cortical hyperostosis
- perilesional marrow or periosteal edema (in the absence of a recent fracture)
- early arterial enhancement
- intense uptake and intense FDG avidity on PET
Old bone infarct: in bone infarct, calcification results from ischemic ossification occurring at the interface between dead and viable bone. It forms a serpiginous peripheral rim.