Chondrogenic Lesions of the Skeletal System Using Radiographs, CT and MRI

Benign Tumors: Chondroma, chondroblastoma,"nchondromyxoid fibroma, osteochondroma"nChondroma"n1. Enchondroma"n2. Periosteal Chondroma"n3. Enchondromatosis"n4. Metachondromatosis"nEnchondroma is a benign metaphyseal tumor. The"nmajor differential diagnoses are bone infarct and"nchondrosarcoma. Calcification in enchondroma"nhas a popcorn appearance and on radiographs and"nCT they may be counted. Calcified bone infarct"nhas an appearance similar to rotten metal. Central"nchondrosarcoma shows cortical erosion more than"ntwo thirds of the thickness of cortex and also periosteal"nreaction. Pain and growth of lesion in adulthood raises"nthe possibility of malignant transformation."nPeriosteal chondroma: This lesion arises from the"nperiosteum without involving the medullary bone."nThe most common location is the upper humerus."nEnchondromatosis reveals multiple enchondromas,"npredominantly involving one side of the skeleton."nMalignant transformation is the major complication"nof enchondromatosis. In malignant transformation,"nMRI shows that perichondrium is more than 1 cm"nthick in adults and more than 3 cm thick in children."nIn the hands and feet, enchondromatosis should not"nbe confused with fibrous dysplasia. Mafucci syndrome"nis enchondromatosis associated with cavernous"nhemangiomas with a prognosis worse than enchondr"nomatosis."nMultiple hereditary cartilaginous exostoses: This is"nof metaphyseal origin and pedunculated forms grow"naway from the adjacent joint. Sessile osteochondromas"nare broad based; if their surface is irregular they are"nsuspicious of malignancy. Pain and growth of the"nlesion after closure of the epiphyseal plate are warning"nsigns of malignant transformation. In malignant"ntransformation MRI shows that perichondrium is"nmore than 1 cm thick in adults and more than 3 cm"nthick in children."nChondroblastoma: This is a benign tumor, seen before"nclosure of epiphyseal plate, with a sclerotic border."n30 to 50% show calcification. CT and MRI confirm"nradiographic findings. The tumor is hypodense in T1"nand hyperdense in T2 and post gadolinium injection"nfat suppressed T1 images. CT and MRI confirm"nradiographic findings."nChondromyxoid Fibroma-A benign, eccentric, ovoid,"nmetaphyseal tumor with recurrent tendency. It rarely"nshows calcification. The tumor is hypodense on T1 and"nIran J Radiol 2011, 8 (Supp.1) S65"nhyper dense on T2 and post gadolinium studies show"nhyperintensity beyond the tumor. It has a tendency"nfor recurrence. Non-ossifying fibroma is a self healing"nmetaphyseal fibrous defect and not a tumor, diamond"nshaped in