Enchondromas are benign bone tumors derived from cartilage cell. Real prevalance is unknown. There is no sex predilection. They are mostly found in the short tubular bones of the hand. Long bones, particularly femur, humerus and tibia are also involved. Enchondromas in the hand and foot present with pain or pathologic fractures due to frequent trauma, whereas long bone lesions are incidentally found during radilogical examinations for adjacent joint problems. Radiological findings differ for short tubuler and long bones. It manifests as an expansile lesion with cortical thinning and faint calcifications in short tubular bones, while in long bones a metadiaphyseal lesion is seen with irregular calcifications in most, but without sclerotic margins, that has minimal or no cortical changes. Enchondromatosis and Mafucci`s syndrom are other forms of this disease. Followup is sufficient for asymptomatic enchondromas. Curettage and grafting is the classical treatment if surgery is required. Malignant change to low grade chondrosarcoma is seen in 1% of enchondromas and 20–50% in multiple lesions. It is sometimes very difficult to make a diagnosis between enchondroma and low grade chondrosarcoma for clinicians, radiologists and pathologists; multidisciplinary approach helps to overcome this problem.
Osteochondroma is the most common benign bone tumor, with a predilection for males. A mutation in the EXT genes is the reason. Symptoms usually arise in the first two decades. The common locations for osteochondromas are around the knee, proximal humerus, distal tibia and proximal femur. Flat bones may also be involved. Patients present with indolent, immobile bony prominences, but pressure on the neighboring soft tissues, bursitis, fracture, overgrowth of the lesion and malignant change also cause symptoms. Since these lesions arise from physeal cartilage, these lesions stop with the cessation of growth. Multiple osteochondromatosis is an autosomal dominantly inherited form with multiple exostoses, short stature and deformities. Risk of malignant change is less than 1% and estimated to be around 5% for solitary and multiple lesions, respectively.