Fig. 5From: A complex histopathological challenge: suspicion of an osteoblastoma-like osteosarcoma arising from the second thoracic vertebra in a catHistological presentation, Hematoxylin & Eosin: a The expansively growing neoplastic mass develops (arrows) within the intertrabecular spaces of the irregularly arranged woven bone (*), which is attached to the fibrous periosteum in which chondrocytes (^) and osteoblasts are present. ‡ = base of the spinous process of T1. b Close to the periosteum the tumour is composed of larger lakes of amorphous osteoid (*) surrounded by polygonal osteoblasts and occasional multinucleated osteoclasts (+) 400x. c Van Gieson: Mass further away from the periosteum. Osteoid production was less and short fascicles of spindle cells or polygonal cells (yellow) surround small islets of osteoid (red) 100xBack to article page