CLINICAL SUMMARY Fibrous dysplasia results when fibrous tissue and metaplastic bone replace marrow and lamellar bone. It is typically an asymptomatic, incidental discovery; however, when a large segment of a…

Cellular Elements of Bone Osteoblasts, Osteocytes, and Osteoclasts SUMMARY Bone is formed by osteoblasts, maintained by osteocytes, and remodeled by osteoclasts. Osteoblasts Osteoblasts synthesize type I collagen and produce alkaline…

CLINICAL SUMMARY Enchondromas are thought to be physeal cartilage rests that failed to ossify during skeletal growth. They are frequent, incidental discoveries in the metaphyseal humerus and femur during radiographic…

CLINICAL SUMMARY Osteoblastoma is an uncommon, benign, but locally aggressive osteoid-producing tumor. Treatment is thorough curettage or marginal excision. Osteoblastoma tends to occur more commonly in the spine than in…

CLINICAL SUMMARY Osteochondromas are disorders of physeal bone growth in which histologically normal bone grows transversely away from the center of the growth plate. The large majority of patients with…

Campanacci Disease, Cortical Osteofibrous Dysplasia, Ossifying Fibroma CLINICAL SUMMARY Osteofibrous dysplasia is a distinctive intracortical lesion almost always seen in the anterior tibial cortex. Histologically, it resembles fibrous dysplasia. Small…

CLINICAL SUMMARY Chondromyxoid fibroma is a rare benign bone tumor with a predilection for the metaphysis of long bones and a distinctive histologic appearance. Curettage is adequate for most cases….

Eosinophilic Granuloma, Histiocytosis X CLINICAL SUMMARY Langerhans cell histiocytosis presents as a painful lytic bone lesion in children. It is most commonly monostotic, in which case it is also termed…

Codman Tumor CLINICAL SUMMARY Chondroblastoma is an uncommon bone tumor, found almost exclusively in the epiphysis of long bones or epiphyseal equivalents, such as an apophysis or the patella. Diagnosis…

Simple Bone Cyst CLINICAL SUMMARY Unicameral bone cysts are most common in children and adolescents and are thought to result from transient failure of the physeal cartilage to ossify. They…