Bone remodeling in pathologic conditions. A scanning electron microscopic study.

Bone remodeling in pathologic conditions was studied with the scanning electron microscope (SEM). Benign and malignant ossification were examined in cases of myositis ossificans, ossifying fibroma, osteoid osteoma, and osteosarcoma, Resorption of bone due to invasion by non-ossifying tumors was found in cases of squamous cell carcinoma, adenocarcinoma, ameloblastoma, and multiple myeloma. Bone formation due to excessive production of growth hormone was studied in a case of acromegaly. Resorption of bone due to pathologic processes resembled the pattern found in surfaces which were undergoing resorption by osteoclasts. Lamelar-cortical bone formation in acromegally was similar in nature to normal bone. The deformities were rleated to the excessive continuous osteogenesis that occurs in these instances. Neoplastic ossification was characterized by calcifying globules, the diameters of which ranged from 1 to 3 micron. The surfaces of these globules were constructed of minute calcospherites with diameters ranging from 0.1 to 0.3 micron. It is suggested that the pattern of globular calcification is similar to the type that was found with the SEM in fetal bone and cartilage, during healing of fractured bone, and also with the TEM in normal and pathologic calcification.