Osteochondroma is also called osteocartilaginous exostosis. It is the most common primary benign tumor of bone and constitutes 35% to 50% of benign bone neoplasms.The actual incidence is may be higher as many lesions are never reported because they are asymptomatic.
Osteochondroma can occur as hey may occur as solitary lesions or can be a part of multiple hereditary exostoses, which is most often inherited as an autosomal dominant trait although it can also occur sporadically.
Multiple hereditary exostosis lesions show significant variability in size, number, and distribution.
In true sense, osteochondromas are developmental abnormaility of the cartilage which results in formation of a cartilage capped bony protrusion on the surface of a bone.
They most oftenoccur in the distal femur, proximal tibia, and proximal humerus and ilium. Thy most commonly occur in second and third decade of lif.
Males are affected twice as common as females
In their usual course osteochondroma grow as long as there is skeletal growth. If an osteochondroma grows after skeletal maturity has been achieved, a malignant change should be suspected.
Painless hard slow growing swelling is the usual complaint. Pain might occur due to pressure on adjacent tissues like tendon, muscle, or nerve or bursal inflammation or a fracture of the osteochondroma.
A palpable mass is usually the only finding on clinical examination. Long standing lesions may lead to angular deformities of the bone or limb-length discrepancies.
Lesions which occur near the joint may cause restriction of motion. In spine the osteochondroma may lead toand symptoms secondary to cord or root compression
On radiographs, osteochondromas can be sessile or pedunculated (have a stalk). The lesion typically arises from the metaphysis of a long bone, with a stalk that is continuous with the adjacent cortex and is oriented away from the epiphysis.
Sessile lesions demonstrate a flat, plateau-like protuberance.
Usually clinical examination and xay are sufficient to diagnose these lesions. In cases of doubt CT and MRI are excellent imaging modalities.
Most of the osteochodromas ar eleft as such as they do not cause any symptoms.This lesion is almost always operated for its complications which include painful lesion, pressure effects, restriction of motion, compression on adjacent structures, deformity of the bone, fracture of osteochondroma, bursitis and malignancy.
In such cases complete removal of the lesion is sought. An incomplete removal may lead to recurrence.
Osteochondromas need not routinely be removed especially in skeletally immature individuals when the lesion is in proximity to the physis.
Malignant Changes In Osteochondroma
Malignant change in osteochondroma almost never occurs in growing age. As such malignant change is not very common but it does occur in adulthood to the incidence of 1% . An increase in size and pain in adulthood are common symptoms that should alert one to possibility of malignant change in the osteochondroma.
The malignancy associated with osteochondromas is most often chondrosarcoma, although malignant fibrous histiocytoma and osteosarcoma have been reported. osteochondrmas in pelvis, scapula, ribs, spine (Central Lesions) carry a higher risk of malignant transformation.
Treatment is wide excision of the entire lesion with a surrounding rim of normal tissue.