This is a CT scan of a 2-year old male mixed-breed dog who presented with a history of mouth pain and an audible click when opening his jaw…
This patient has an expansile mass of mixed bone and soft tissue density which is originating from the vertical ramus of the right mandible. There is poorly marginated lysis of the mandible adjacent to the mass, which means the lesion should be categorized as aggressive. Although the patient is young, a primary bone tumor such as osteosarcoma, parosteal osteosarcoma, or a tumor of dental origin should be considered as the most likely differentials. Remember that osteosarcoma primarily affects two age groups; young dogs under 24 months, and older dogs over ~6-7 years of age.
The final diagnosis for this patient was chondroblastic osteosarcoma.