[Peculiar cemental lesion of the jaws--its pathological entity and natural history].

Two hundred fifty-five solitary and 42 multiple cases of fibro-osseous lesions of the jaws, and 74 cases of sclerosing osteomyelitis were studied clinico-pathologically, in order to discuss the entity of peculiar cemental lesion with sequester-like appearance, which occurs mainly in the mandibular molar area of over middle-aged females. Four allied lesions, including the sequester-like cemental lesion, were revealed. They were provisionally designated sequestrated cemental masses, cemental masses, focal cemento-osseous dysplasia, and periapical cemental masses respectively, because no entities that were consistent with them could be found in the classifications of World Health Organization (WHO). The above- mentioned peculiar cemental lesion was equivalent to sequestrated cemental masses, which consist of sclerotic cementum and/or osteocementum with inflammation. Cemental masses and periapical cemental masses were related to sequestrated cemental masses. Focal cemento- osseous dysplasia was considered to be a counterpart of lesion which had been recently reported by Summerlin et al. In consideration of similarity and continuity of the histological and clinical findings, the four allied lesions were thought to be arranged in a continuous spectrum of fibro-cemento-osseous dysplasia of the jaws, along with periapical cemental dysplasia and florid cemento-osseous dysplasia that are mentioned in the WHO classification.