A 60-year-old female presented with asymptomatic failing mandibular dental implants. Computed tomography (CT) showed a partially calcified, hypointense lesion within the soft tissues, measuring 1.3 x 0.8 x 1.0 cm along the buccal cortex. Incisional biopsy demonstrated a basaloid type of tumor composed of sheets of cells with plump ovoid nuclei, distinct nucleoli, and scant eosinophilic cytoplasm. Mitoses were present, averaging about 2 per 10 high power fields with scattered individual apoptotic cells. Numerous laminated calcified bodies (Liesegang rings) were observed with confluence of these bodies to form larger foci of dystrophic mineralization. These features clearly established the malignant nature of this tumor. Immunohistochemically, the tumor was positive for synaptophysin, focally positivity for CAM 5.2 and had a Ki-67 proliferation index of approximately 25%. This is the first report of a tumor with features of a malignant variant of calcifying epithelial odontogenic tumor and neuroendocrine differentiation.
Keywords: calcifying epithelial odontogenic tumor; dental implant; malignant variant; neuroendocrine.