Vertebral metastasization of a prostatic adenocarcinoma

Vertebral metastasization of a prostatic adenocarcinoma and ossifying periostitis in the lumbar vertebrae (L5 and L6) of a 12-year-old mixed breed dog. The neoplastic cells have invaded the peritoneal fat, the omentum, the adrenal glands and the sub-lumbar retroperitoneal fat, also affecting the vertebral periosteum, which reacted to their presence by forming well differentiated bone with no trabecular organization (ossifying periostitis), leading to fusion of the two affected vertebrae.