Microradiographic and microscopic investigation of a rare case of complex odontoma.

An extremely rare case of odontoma that erupted into the oral cavity is presented. The lesion was surgically removed from a 14-year-old girl and examined by soft x-ray radiography, microradiography, and microscopy to determine whether the lesion was complex or compound. Macroscopically, the surface of the lesion was slightly lobular and solid, resembling the surface of an osteoma. The soft x-ray radiograph obtained from the surgical specimen showed radially arranged radiopaque spicules. Microradiographically, dentin was shown to be present in relatively large quantities and to form the bulk of the tumor, with irregular enamel and cementum in small quantities. There were numerous, comparatively well-formed, enamel-free, toothlike structures in the peripheral region of the tumor. Microscopically, the toothlike structures were seen to be arranged radially; this corresponded to the microradiographic findings. Each structure consisted of a central core of pulp tissue encased in a shell of dentin. In the central area of the mass, there was an irregular conglomerate of dentin, enamel, cementum, and pulp tissue. The findings showed that the lesion was a complex odontoma.