Active cysts usually develop in patients younger than 10 years of age. Typically, the cyst abuts the growth plate and occupies most of the metaphysis; it is expansile with a…

Diagnostic Studies. A radiolucent lesion with a ballooned expansion of the bone cortices (“finger in balloon”) is the radiographic hallmark of an aneurysmal bone cyst. Although some lesions appear to…

Eosinophilic granuloma usually occurs as a solitary, symptomatic lesion in children younger than 20 years of age but can occur as multiple tumors at any age and at any site….

Diagnostic Studies. The radiographic hallmark is an epiphyseal radiolucent lesion with fine punctate calcifications suggestive of a cartilaginous lesion. The tumor is usually bordered by a well-defined margin of reactive…

Monostotic lesions generally occur in the proximal femur, proximal tibia, mandible, and ribs. Polyostotic disease, which usually presents earlier, may be unilateral or widespread, affecting long bones, hands, feet, facial…

Diagnostic Studies. The lesion commonly develops in the metaphysis of the distal femur or distal tibia and is eccentrically located, usually within or adjacent to the cortex. Radiographs reveal a…

Diagnostic Studies. Periosteal chondromas appear on radiographs as a radiolucent oval or oblong defect visualized as a crater-like deformity of the periphery of the cortex. The lesion is underlined by…

The initial clinical sign is a hard, painless mass fixed on the bone. Symptoms, when present, are usually due to irritation of the overlying soft tissues that may or may…

Enchondromas can occur anywhere in the skeleton. In very rare cases, a benign enchondroma undergoes malignant transformation into secondary chondrosarcoma (see Plate 6-17). However, aggressive appearing lesions in the hands…

Diagnostic Studies. An intense bony reaction to a small nidus is the radiographic hallmark of osteoid osteoma. Radiographs reveal an oval radiolucent nidus only 3 to 5 mm in diameter…