The sections show blood, fragments of lamellar bone and a small fragment of lesional tissue consisting of anastomosing bony trabeculae rimmed with osetoblasts, and osteoid with variable degrees of calcification. There is no nuclear atypia, necrosis or mitotic activity. Occasional multinucleated-giant cells with abundant eosinophilic cytoplasm are present.
Bone, right hip, biopsy - scant lesional tissue with features consistent with an osteoid osteoma, see comment.
The lesional fragment is very small (largest dimension is measured as 0.22 cm). The scant lesional component of this small biopsy may not be representative of the lesion as a whole. If atypical clinical or radiologic features are present, or arise in follow-up, a re-biopsy should be considered.
The sections show many multinucleated giant cells, hemosiderin-laden macrophages in collagenous stroma with bland epitheliod cells with pale nuclei. Foam macrophages are present focally.
Soft tissue mass, left ankle, biopsy:
- Tenosynovial giant-cell tumour, diffuse type (pigmented villonodular synovitis).