Juxtacortical<unk>  was first discovered by Lichtenstein and Hall in 1952. The term juxtacortical<unk>  was first coined by Jaffe in 1956.<unk>  may be classified according to location of the outgrowth into 3 groups that include enchondrom, periosteal<unk>  and synovial<unk> . Enchondromas arise from rests of growth plate cartilage or chondrocytes that are normally involved in the production and maintainence of the cartilaginous matrix, which consists mainly of collagen and proteoglycans. Genes involved in the pathogenesis of enchondromas and periostal<unk> s include isocitrate dehydrogenase 1 (IDH1) and isocitrate dehydrogenase 2 (IDH2). On gross pathology, small (usually less than 3 cm), translucent, grey blue, nodular lesions with occasional calcifications are characteristic findings of<unk> s. Enchondromas may be single or multiple. Multiple enchondromas are associated Maffucci syndrome, Ollier disease and metachondromatosis. The cause of<unk> s has not been identified. However, enchondroma is believed to occur either as an overgrowth of the cartilage that lines the ends of the bones, or as a persistent growth of original embryonic cartilage.The incidence of osteochondromas is approximately 30,000 per 100,000 of all cartilage tumors and 2,000 per 100,000 of all bone tumors.The prevalence of enchondromas is approximately 12,000 - 24,000 per 100,000 individuals of benign bone tumors and 3000 - 10,000 of all bone tumors. Patients of all age groups may develop enchondromas. The incidence of enchondroma peaks in the third and fourth decades of life. Enchondroma affects men and women equally.<unk>  is usually diagnosed incidentally. Common complications of<unk>  include malignant transformation into a low grade growth disturbance, pathologic fracture, especially in short tubular and recurrence. Benign<unk> s have a good prognosis with aprropriate treatment. The majority of patients with enchondroma are asymptomatic. Less common symptoms of enchondroma may include pain, enlargement of the affected digits, and slowing of affected bone growth and asymmetrical bone deformities. There are no diagnostic lab findings associated with<unk> . Findings on an x-ray suggestive of<unk>  include well-defined or sclerotic border, sharp zone of transition, confinement by natural barriers, lack of destruction of the cortex and lack of extension into the soft tissue. Findings on CT scan suggestive of enchondroma include sharply defined scalloped margins, expansion of the overlying cortex may be present, no periosteal reaction and soft tissue mass. Findings on MRI suggestive of<unk>  include well circumscribed, lobulated mass replacing the marrow for enchondroma, lobulated soft tissue lesion that is abutting the cortex and evidence of pressure erosion on neighboring bone, with no evidence of medullary bone or soft tissue edema for periostal<unk>  for periostal<unk> . Surgery is not the first-line treatment option for patients with asymptomatic and benign<unk> . Surgery is usually reserved for patients with either malignant transformation and pathological fracture.
Chondroma
Ganglion cyst
Epidermoid cyst
Klatskin tumor
Acrospiroma
Dermoid cyst
Colloid cyst
Neurofibroma