Most osteochondromas are located at or near the epiphyseal-metaphyseal junction of the long bones, especially at the lower metaphysis of the femur and the upper metaphysis of the tibia.
Osteochondromas are usually found in young patients (60 to 80% of patients with these tumors are younger than 21 years of age), and there is no predilection for either sex.
While osteochondromas are benign lesions, malignant transformation does occur in almost 1% of cases.
Many osteochondromas are asymptomatic and therefore escape detection.
To the best of our knowledge, this is the first case of an osteochondroma involving the nasal dorsum to be reported in the English-language literature.
Osteochondromas may occur in any bone formed by enchondral ossification.
Osteochondromas are noticed because of their size or through such complications as bursitis, fracture of the stalk, or impingement on nerves or vessels resulting in ischemia or pseudoaneurysm formation.
Grossly, osteochondromas are sessile or pedunculated bony projections covered by a smooth, rounded to bosselated, cartilaginous cap of uniform thickness, usually a few millimeters thick (Figure 8, B and C).
Osteochondromas usually share the destiny of the epiphyseal plate, with loss of their cartilaginous cap at the same time as the epiphyseal plate closes.
If these findings are confirmed, solitary and multiple osteochondromas may be considered true neoplasms.
Histology confirmed an osteochondroma
with no malignant cells and vessel consistent with pseudoaneurysm formation.
The most frequent cause of progressive dislocation of the radial head in association with osteochondroma is distal placement of the ulna, which produces alterations of the distal ulnar growth plate, causing progressive ulnar shortening and bowing of the radius, and finally to radial head dislocation.
In rare cases, the injury occurs after the development of an osteochondroma in the proximal ulna, which leads to dislocation of the radial head as a result of local compression, such as in the case described here.
Its occurrence as a result of pressure by an osteochondroma has only been described in the literature once in children, the case of a nine-year-old boy.
The parents had no relevant previous medical or surgical history, nor were there any past instances of solitary osteochondroma or multiple hereditary osteochondromata in the family.