Computed Tomographic Findings of Ischemic Necrosis of the Accessory Carpal Bone in a Dog

A 1-year-and-9-month-old Golden Retriever presented with a 9-month history of right thoracic limb lameness. Radiographs revealed a monostotic, expansile lesion of the right accessory carpal bone (ACB). A computed tomography (CT) confirmed the aggressive nature of the lesion, demonstrating multifocal moth-eaten osteolysis, sclerosis, periosteal reaction, and flexor carpi ulnaris tendinopathy. Differential diagnoses included the ischemic necrosis of the ACB, osteomyelitis, and primary bone neoplasia. Histopathology confirmed osteonecrosis. This case highlights the value of CT in evaluating aggressive carpal lesions and identifies ischemic necrosis as an important differential diagnosis. This case represents the first CT description of this disease in dogs.