Fig. 4
From: Intra-articular osteoid osteoma as a differential diagnosis of diffuse mono-articular joint pain
Osteoid osteoma, microscopic findings. a Overview. The cellular tumour (mid and lower left) shows irregular bone trabeculae partly consisting of osteoid and embedded in fibrous stroma. Cortical bone (upper left and upper and lower right) appears sclerotic. b Detail. The tumour tissue consists of woven bone trabeculae (1) covered by enlarged osteoblasts (2) and scattered multinucleated osteoclasts (3). The fibrous stroma contains dilated blood vessels (4). There is no evidence of tumour necrosis or cellular atypia. a Undecalcified preparation, staining method: toluidine blue, original magnification: 25×; b EDTA decalcification, staining method: haematoxylin and eosin, original magnification: 200 ×