Multiple Cartilaginous Exostoses

12 July, 2019

Case example

It’s not always the elbow – even in a Labrador!

A 7 month-old, male Labrador Retriever puppy presents with right thoracic limb lameness.

CT findings

There are small, lobular mineral attenuations in the region of the soft tissues of the greater tubercle of the humeri bilaterally. These findings are more pronounced along the right side, characterizing mild asymmetry. The soft tissues of the right craniolateral joint compartment mildly contrast enhance. The right glenohumeral joint capsule is thickened and also mildly contrast enhances.

Conclusions and learning points

The primary differential diagnosis is multiple cartilaginous exostoses (MCE). MCE represent benign proliferations close to enchondral ossification centers and can occur multifocally and bilaterally symmetric throughout the body. A genetic component of MCE is assumed because of the familial tendency. Only bones developed by endochondral ossification are affected. The vertebrae, ribs, and long bones represent the most frequent locations. Bones of the carpal and tarsal joints and the skull are spared. Calcinosis circumscripta would be a possible differential diagnosis in this case, which usually occurs in an asymmetrical manner. However, the combination of calcinosis circumscripta and MCE has been reported. These types of lesions are often incidental, but can become clinically relevant and may require surgery when they restrict motion. Malignant transformation of MCE has been reported rarely.


„Imaging Diagnosis: Multiple cartilaginous exostoses and calcinosis circumscripta occurring simultaneously in the cervical spine of a dog” Engel et al., Vet Radiol Ultrasound 2014; 55: 305-9

“Canine multiple cartilaginous exostoses: unusual manifestations and a review of the literature.” Jacobson et al., J Am Anim Hosp Assoc.; 1996; 32:45-51

“Multiple cartilaginous exostosis in a Golden Retriever cross-breed puppy. Clinical, radiographic and backscattering scanning microscopy findings.” Franch et al.; Vet Comp Orthop Traumatol.; 2005; 18:189-93

Images courtesy of Tierklinik Haar