Chondroblastoma--current opinion

Chondroblastoma of bone is rare bone tumor, representing around 1% of benign bone lesions. It is considered a benign lesion, although primary malignant form as well as malignant alteration in the form of chondrosarcoma has been documented. It occurs predominantly in the second decade, more commonly in males. Predilection sites include proximal humeral epiphysis, femoral and tibial condyles, but it can be found in other bones, too (skull, pelvis, posterior vertebral structures, tarsal bones). Radiographically, it appears as an ovoid lesion with thin sclerotic margin, located centrally in the epiphysis. Pathohistologically, it is described as highly cellular tissue, variably differentiated and with discrete granulated to meshy calcification of the matrix and large multinuclear cells present in 20% of cases. Secondary formation of aneurysmal bone cyst has been documented. Tumor is presented with a few nonspecific local symptoms, which makes diagnostic procedure more difficult. Definitive diagnosis is made only by pathohistological verification. A pathological fracture of weakened epiphysis is possible. The treatment of chondroblastoma is strictly surgical, with a view to counteract the propagation into the joint or adjacent soft tissue, and diminish the recurrence rate. Chemotherapy is not indicated for treatment of this tumor, and radiotherapy is contraindicated as it stimulates malignant alteration. If malignant chondroblastoma of bone is verified pathohistologically, radical treatment by surgical resection is indicated, also avoiding any adjuvant therapy.