Fifty‐six cases of osteosarcoma of the maxilla or mandible are analyzed for clinical, roentgenographic and histologic character, therapy and prognosis. The mean age at the onset of symptoms for osteosarcoma of the jaws is about a decade later than for osteosarcoma of other bones. Pain is less often associated with osteosarcoma in the jaws than it is in the long bones. Roentgenographic evidence of a symmetrically widened periodontal membrane space may be a significant early finding. There is no correlation between the histologic character of the tumors and prognosis but prognosis does appear to vary depending upon the specific site of origin within the bones. The worst prognosis is associated with maxillary antral osteosarcomas and mandibular symphysis osteosarcomas have the best prognosis. Radical surgery is the treatment of choice. Approximately one third of the patients had biopsy‐proved metastasis, with the lung being the most common site.

An analysis of the clinical, radiographic, histologic and follow‐up data on 249 cases of lesions of periodontal membrane origin is presented. Such lesions may be cementoid, osteoid, mixed (cemento‐osteoid) or fibrous. These tumors may be single or multiple and usually behave in a benign fashion. Occasionally they may act in an aggressive manner and attain giant size, although none metastasize. The benign fibro‐osseous lesions of periodontal membrane origin are more prevalent in the jaws than fibro‐osseous lesions of medullary bone origin. The use of polarized light was most helpful in distinguishing mature cementoid lesions from tumors with mature lamellar bone; the former have finer lines of parallel birefringence. Fibrous dysplasia has often been misused as a diagnostic term and was found not to be prevalent as a fibro‐osseous jaw lesion. Fibrous dysplasia has its own particular histologic features, and the immature “woven” bone within the lesion polarizes in a random birefringent pattern.