Central (intraosseous) adenoid cystic carcinoma of the mandible: report of a case with periapical involvement.

Primary intraosseous salivary gland tumors are rare, with mucopidermoid carcinoma being the most frequent histotype. The authors present a case of adenoid cystic carcinoma, located in the mandibular incisor region, associated with pain. Endodontic treatment resulted in increased pain and progressive mandibular expansion. An apicoectomy was conducted, and an intraosseous adenoid cystic carcinoma was diagnosed at histological examination. The patient was treated by wide surgical resection, and is alive and well without recurrences or distant metastases 14 yr after the original diagnosis. The case presented herein calls attention to the preoperative clinical diagnosis of periapical lesions. Radiologically, focal sclerosing osteitis, cementoblastoma, cementifying and ossifying fibroma, periapical cemental dysplasia, complex odontoma, and calcifying epithelial odontogenic tumor should be considered in the differential diagnosis. In addition the unusual occurrence of salivary gland tumors in intraosseous location stresses the importance of systematic histological examination of any tissue sample obtained after endodontic procedures.