Expansile keratocystic odontogenic tumor in the maxilla: immunohistochemical studies and review of literature
A 57-year-old man was referred to the clinic for the evaluation of facial swelling and asymmetry. The panoramic view showed a large cystic lesion from the anterior maxilla to the entire left side of the maxilla and maxillary sinus. The teeth involved showed no deviation, but slightly resorbed roots were detected. In the computed tomography (CT) views, the cystic tumor was expanded to the buccal and palatal bony wall with partial disruption of cortical bone.() The lesion was tentatively diagnosed as KCOT because of its aggressive expansion with homogenous fluid-filled lumen. The patient underwent endodontic treatment for all teeth involved, and the expansile maxillary tumor was radically excised with Weber-Ferguson incision, showing no recurrent sign for more than 5 years' follow-up period.()\nIn the histopathological features of H&E-stained slides, thin lining of stratified squamous epithelium and thin parakeratotic surface on the lumen side of the cyst were observed, indicating KCOT. To characterize this tumor, specimens were immunostained with BCL2, BAX, Ki-67, and p53 and p63 antibodies. For the immunohistochemical analysis, tumor specimens were embedded in paraffin blocks, and then cut into 4-µm sections and mounted on silane-coated glass slides. Sections were maintained at room temperature for 12 hours, and then deparaffinized; after hydration they were immunostained using an automated immunostainer (BenchMark XT; Roche Korea, Seoul, Korea). The primary antibodies used and immunohistochemical staining results are summarized in . Positive immunostaining intensities were graded as +++, ++, +, and - for strong, moderate, weak, and negative staining, respectively.\nIn the immunostained slides, p53 and p63 proteins were strongly expressed in the lining epithelium of the tumor, BCL2 and Ki-67 were moderately expressed in the epithelium and stromal tissues of tumor, and BAX was almost negatively detected.(, )