Presentation
Pain in both knees.
Patient Data
A well-defined small calcified area with rings and arcs appearance noted in the lower diaphyses of right femur with a narrow zone of transition.
A well-defined lobulated intramedullary T2, STIR hyperintense and T1 hypointense lesion with multiple areas of signal drop within noted in the lower diaphyses of the right femur with variable enhancement. Associated synovitis with mild effusion noted.
Case Discussion
Enchondroma occurs in bone formed by cartilage and are solitary, eccentric, non-expansile or expansile lesion sometimes detected incidentally.
Differentials include bone infarcts and chondrosarcoma. Infarcts are densely sclerotic with serpiginous border, whereas chondrosarcoma depends more on clinical features and is difficult to differentiate from enchondroma radiologically.
While reporting, more importance should be given to looking for aggressive features as they can warrant surgery.