Fig. 1

Conventional AP and lateral radiographs (top left and top middle) show an expansive bubbly lytic bone lesion in the diaphysis-metaphysis of the right distal radius with a narrow zone of transition, nonsclerotic margins, cortical thinning and destruction, and an accompanying large soft-tissue mass which appears to compress the distal ulna with bowing of the latter. Bone scintigraphy (top right) shows no increased uptake at the location of the lesion. MRI with coronal T1-weighted (bottom left) and gadolinium-enhanced T1-weighted (bottom middle) images, and axial T2-weighted and gadolinium-enhanced fat-suppressed T1-weighted images (bottom right) are in keeping with the conventional radiographic findings, and also demonstrate no signs of invasion in surrounding muscles or ulna. Remarkably, in the center of the lesion there is low signal on all sequences (arrows), most strikingly on the T2-weighted sequence. Because the combined imaging features suggest a slow-growing (most likely benign) process with fibrotic components, the differential diagnostic considerations include desmoplastic fibroma, and (less likely) giant-cell tumor or fibrous dysplasia