An 11-year-old boy attended the surgery with his father. He had felt a lump on his left upper arm the previous evening after a game of football. He did not recall any obvious trauma. The lump was painless and he was otherwise entirely well with full range of movement in his arm.
On examination, there was no swelling or inflammation but on palpation of his upper arm, there was a very hard immobile lump, which appeared to be attached to the upper part of the humerus. His father was obviously worried.
What is the diagnosis, management and differential diagnosis?
Diagnosis and management
The diagnosis is osteochondroma or osteo-cartilaginous exostosis, which is a benign tumour containing both bone and cartilage, usually occurring near the end of a long bone. It takes the form of an outgrowth on the surface of the bone. Most occur in the distal femur, proximal tibia or as in this case, in the proximal humerus.
Osteochondromata tend to occur in the second decade of life and may occur as multiple lesions. These benign tumours do not spread beyond the affected bone but may grow in size as the child grows until skeletal maturity. Very rarely osteo-chondroma may become malignant in later life.
A plain X-ray of the humerus was arranged, which confirmed the presence of the osteochon droma at the junction of the proximal third and distal two-thirds of the humerus with no sinister features. If it grows, follow-up X-rays may be needed.
Osteochondroma do not require treatment unless they becomes very large, lead to fracture, or become painful, which may occur if they involve tendons or nerves. Treatment is always surgical.
Possible different diagnoses
- Fracture of humerus.
- Malignant condition associated most often with osteochondroma.
- Tends to be low grade.
- Rarely metastasise and have a better prognosis than other forms of the disease.
- Very rare.