Fig. 5

Recurred BPOP arising from the distal ulnar diaphysis (same patient shown in Fig. 4). Three years after surgery, BPOP recurrence presents as a cortex-based completely ossified mass, which is contiguous to the palmar-radial aspect of the ulna. On MRI, the ossified component of the mass is hyperintense on both T2-weighted (a, b) and T1-weighted (c) sequences. After contrast administration, contrast enhancement is noted on fat-saturated T1-weighted sequence (d). No cortical breakthrough is seen on CT (e). White arrow points at BPOP in all images. Dashed arrow points at the outermost cartilaginous layer of BPOP in (b)