Usefulness of radiography in differentiating enchondroma from central grade 1 chondrosarcoma.
OBJECTIVE
The purpose of this study was to evaluate clinical symptoms and radiographic features that allow radiologists to differentiate between enchondroma and central grade 1 chondrosarcoma. Such differentiation is important because of differences in management.


METHODS
Clinical symptoms and location and size of 35 enchondromas and 43 central grade 1 chondrosarcomas were analyzed. Radiographic features were assessed independently by three observers. The chi-square test and linear discriminant analysis were used to identify features with discriminating strength. Kappa values were calculated to validate the consistency of observations among observers. A consensus diagnosis made by histology and long-term follow-up was used as the standard.


RESULTS
No statistically significant correlation was found between clinical symptoms and the benign or malignant nature of the neoplasms. Grade 1 chondrosarcomas were more likely to be found in the axial skeleton and in flat bones. Also, chondrosarcomas were significantly larger than enchondromas (p < .001). Ill-defined margins and lobulated contours were the only morphologic features seen on radiographs that allowed significant discrimination (p = .004 and .009, respectively). An optimal combination of four radiographic features still left 72 of the 78 lesions with a 10-90% probability of malignancy, indicative of poor discriminating power. Kappa values generally showed poor to fair agreement.


CONCLUSIONS
Location in the axial skeleton and size greater than 5 cm are the most reliable predictors of central grade 1 chondrosarcoma. Morphologic features seen on radiographs and clinical symptoms do not improve the ability to differentiate between enchondromas and central grade 1 chondrosarcomas.
Geirnaerdt
M J
MJ
Department of Radiology, Leiden University Medical Center, The Netherlands.
Hermans
J
J
Bloem
J L
JL
Kroon
H M
HM
Pope
T L
TL
Taminiau
A H
AH
Hogendoorn
P C
PC
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001859:Bone Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D002812:Chondroma / Q000000981:diagnostic imaging* / Q000473:pathology; D002813:Chondrosarcoma / Q000000981:diagnostic imaging* / Q000473:pathology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011859:Radiography; D012189:Retrospective Studies; D012680:Sensitivity and Specificity