Chondrosarcoma in the radius of a horse.

This research paper details a case study of a Thoroughbred stallion diagnosed with chondrosarcoma in the radius, presenting with progressive lameness, carpal swelling and weight loss. The study provides an evaluation of the tumor’s characteristics and its degree of invasion to the joint and bones.

Diagnosis of the Condition

• The Thoroughbred stallion showcased progressive lameness, weight loss, and swelling in the carpal region leading to an examination.
• Upon radiography, it was discovered that there was a destructive lesion in the caudomedial, distal portion of the radius, a long bone located in the forearm region.
• A tumor-core biopsy then confirmed the diagnosis of chondrosarcoma, which is a type of cancer that affects the bones and joints.

Evaluation of the Tumor

• Upon necropsy, there was a gross and histologic evaluation of the neoplasm. A neoplasm is an abnormal growth of tissue, which can be indicative of benign or malignant growths.
• The chondrosarcoma was found to be at the distal end of the radius. The distal end is the lower part of the bone which is closer to the wrist.
• The evaluation revealed that the chondrosarcoma was locally invasive. This means that the tumor had spread from its initial location at the distal end of the radius to nearby locations.
• The tumor had infiltrated the radiocarpal joint capsule and invaded the carpal bones. This means the tumor had spread to the capsule that surrounds the joint of the radius and carpus (wrist) bones, and to the carpal bones themselves.

Malignant Nature of the Tumor

• The infiltrative nature of the tumor revealed its malignancy. Malignant tumors are serious as they grow uncontrollably, invade neighboring tissues and organs, and are capable of spreading to distance places in the body.
• Furthermore, the histologic features of the tumor including cell pleomorphism and presence of mitotic figures confirmed its malignancy. Cell pleomorphism refers to variability in the size, shape, and staining of cells and nuclei within a single lesion. Mitotic figures are indicators of cellular proliferation. Seeing these features in a tumor is usually indicative of a malignant growth.