Diaphyseal and metaphyseal anomalies.
Bone marrow replacement, endosteal patchy lytic resorption and periosteal reaction (single-layer, but irregular). Swelling of adjacent tissue.
Bone surgical biopsy left a hiatus in the cortical bone, on the medial side of the diaphysis.
Productive and lytic changes, hence due to a chronic inflammatory process, with bone marrow replacement by a non-osteogenic non-cartilaginous matrix.