Presentation
Mass on the left arm and limited range of motion.
Patient Data
There is a mostly cortical expansive lesion of heterogeneous density, ill-defined margins, with a sclerotic rim and cortical continuation on the metaphyseal-diaphyseal region of the proximal humerus.
In the proximal metaphyseal-diaphyseal region of the left humerus, there is an expansive lesion with well-defined margins, high signal intensity on T2, and intermediate signal on T1, with a sclerotic rim. There are intralesional foci suggestive of interior calcification. The contrast impregnation is heterogeneous, with areas of low enhancement. The lesion is situated juxtacortically.
The lesion measures 6.4 x 2.1 x 2.5 cm.
Case Discussion
The case was confirmed to be a juxtacortical chondroma by the histopathologic report. Juxtacortical chondromas are usually less than 3 cm.
Chondromas are benign cartilaginous lesions. They usually arise from the medullary canal, being called enchondromas. Rarely, they arise on the cortical of the bone, being called periosteal chondromas or juxtacortical chondromas 1.
An important differential diagnosis is a chondrosarcoma, especially considering that the lesion is more than 3 cm. The presence of endosteal erosion or other signs of aggressiveness would be suggestive of chondrosarcoma - which are not observed in this case.
Case contributed by: Dr Marcelo Bragança and Dr Flávia Costa