Ewing Sarcoma
CLINICAL SUMMARY Ewing sarcoma is approximately half as common as osteosarcoma. It arises from bone marrow and almost always presents with a large soft tissue mass. Compared to osteosarcoma, it…
Giant Cell Tumor
CLINICAL SUMMARY Giant cell tumor of bone is a benign but destructive bone tumor that is usually discovered adjacent to the knee joint in young adults. Although curettage is the…
Osteoid Osteoma
CLINICAL SUMMARY Osteoid osteomas are small, painful, bone lesions that are typically intracortical. Patients usually present with rest pain as well as night pain. Lesions are easily located with nuclear…
Adamantinoma
CLINICAL SUMMARY Adamantinoma is a low-grade malignancy that is found almost exclusively in the tibia and fibula of young adults. Histologically, it is distinguished from other bone tumors by the…
Fibrous Dysplasia
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…
Normal Musculoskeletal Histology
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…
Enchondroma
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…
Osteoblastoma
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…
Osteochondroma
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…
