Abstract
A right mandible tumor was observed in a 10-year-old male Shih-Tzu dog. Histopathologically, neoplastic proliferation of polymorphic epithelial cells with abundant eosinophilic hyaline materials was observed in the gingival lamina propria. Eosinophilic materials were stained positively with Congo red and showed green birefringence under a polarising microscope, indicating amyloid. The amyloid was immunoreactive to anti-ameloblastin and -sheathlin antibodies. Amorphous or concentrically laminated calcification (Liesegang rings) was seen throughout the tumor tissue. This case was diagnosed as calcifying epithelial odontogenic tumor.
