<unk>  is a benign cartilaginous tumor that account for 1% of all bone tumors.<unk>  typically occurs in children and adolescents between 10 and 25 years of age. Male are more commonly affected with<unk>  than female. The male to female ratio is approximately 2:1. The epiphysis of the distal femur, proximal tibia, and proximal humerus are the most common sites. In 1928, Codman first described<unk>  as epiphyseal chondromatous giant cell tumors of the proximal humerus. The exact pathogenesis of<unk>  is not fully understood. Various theories have been postulated such as<unk>  arising from osteoid matrix–containing type I collagen and there is absence of true cartilage matrix production (type II collagen). Recently, a specific mutation in the histone 3 gene H3F3B (K36M), was identified in approximately 95% of<unk> . The hallmark of<unk>  is pain, limping, tenderness and restricted range of motion. If left untreated, few patients with<unk>  may progress to develop lung metastasis. The mainstay of treatment for<unk>  is surgery in form of curettage and bone grafting.
Chondroblastoma
Mycetoma
Esthesioneuroblastoma
Brown tumor
Chondroma
Trichoblastoma
Cylindroma
Osteoblastoma