Many papers were published on both Paget's disease and fibrous dysplasia during the past year. In Paget's disease, evidence for a generalized, probably viral disorder of the skeleton has been adduced, although focal radiologic features dominate the clinical picture. Unusual clinical manifestations were highlighted in several clinical reports. A search for biochemical abnormalities other than increased serum alkaline phosphatase and urinary hydroxyproline levels yielded evidence for secondary hyperparathyroidism in many cases, and also, a confusing array of abnormalities in vitamin D metabolite levels. The application of newer imaging techniques such as computed tomography, MR imaging, bone marrow scintigraphy, and thermography was reported. The year's reports particularly highlighted new forms of effective therapy, including intranasal calcitonin, second- and third-generation bisphosphonates, and gallium nitrate. Finally, the feasibility of joint replacement in arthritic joints secondary to Paget's disease was again documented. Fibrous dysplasia continued to be an enigmatic disorder with no new insights as to etiology. Reports of unusual clinical features, imaging characteristics, bony distribution, and an array of endocrine linkages were prominent. A highlight of the year's reports was the discovery of an increased female sex steroid receptor number of dysplastic cells, and the possibility that sex steroids linked to their receptors may be responsible for the bony overgrowth. Concern was again expressed as to the possibility of malignant transformation of dysplastic lesions and the possible contribution of radiotherapy treatment to sarcoma development.