BONE PATHOLOGY CASE STUDIES

CASE 5 - Osteochondroma

Clinical History:

This is a 15 year old male who presents with a painless mass over the lateral and postero-lateral aspects of the tibia. This mass has been present for three years, and it has slowly expanded. Radiographs demonstrate a bony exostosis growing from the lateral portion of the tibia, but there is no destruction of the tibia. (Slide 5.1)
  1. What does the clinical history tell you about the biologic behavior of this lesion?

    2. The lesion is slow growing and benign.

  2. What is the diagnosis?

    3. This is an osteochondroma, which characteristically has a cartilagenous cap over irregular trabecular bone. All the elements are well-differentiated and benign.

  3. In whom and at what sites is this lesion most common?

    4. There is almost a 2 to 1 male predominance. Peak incidence is teenage to young adulthood, but some occur in older persons. Most occur around the knee, and some in the humerus.

  4. What hereditary disease could be associated with multiple lesions of this type?

    5. Syndromes with osteochondromatosis could include Gardner's syndrome, a rare autosomal dominant disorder with variable penetrance, which includes polyposis of the colon, epidermal cysts, and fibromatoses.